Ground 05 – Spring 2009

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Landscape Architect Quarterly 10/

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Features Trees: Myths, Debates, and Some Truths Round Table Keeping Urban Forests Growing

Publication # 40026106

Spring 2009

Messages

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Letters to the Editor

President’s Message

The Up Front item on cemeteries [Ground 04] covers an imaginative idea from Veronica Schroeder to relieve growing pressures for space in urban areas by using green roofs for cemeteries.

However, I couldn’t help but be a little dismayed by the opening line of the piece, “ When I see a cemetery, I see a huge expanse of land that could be used for other things...” Many cemeteries are enjoyed by people for walking, researching, and enjoyment of green settings. If a major green space, whether a cemetery, an undevelopable ravine, even a golf course, does no more than fill our passing eye with nature, it performs a valuable service.

It has been said that anyone who has planted a tree is an optimist. If so, then our profession must be the most optimistic of all, since landscape architects have collectively planned for and been instrumental in the planting of several hundred thousand trees in the past few years.

So while Schroeder’s idea has merit, perhaps we could also consider ways to make existing cemeteries all the more accessible and useable while still protecting their existence simply as green oases.

The Up Front item on the University of Guelph archives [Ground 04] was a nice reminder about the collection. Any merit in focusing on one or two aspects of the collection as a regular feature, with enough of their graphics to tell stories about their contributions?

The Round Table in Ground 04 was a nice start on seeing ourselves as others do, a useful tool in diagnosis. Philip Weinstein commented about his old partners’ opposing attitudes: one said invisibility was good, the other not. Since I am the person who, several decades ago, said to Philip that invisibility was okay, I would like to clarify. Landscape architecture is a broad field, and sometimes a work of landscape architecture is successful because it enhances without standing out as an intervention.

While such an attitude may not be unique to landscape architecture, I suspect it is more prevalent than in some design professions and perhaps this provides a clue about our nature.

BRAD JOHNSON OALA (EMERITUS), FCSLA, RCA

I must congratulate the Editorial Board on the OALA landmark magazine Ground: Landscape Architect Quarterly, an aesthetic and content-rich quarterly for the landscape architecture profession.

Landscape architecture is my second career. With fifteen years of marketing communications, advertising, and publishing stints in my former work life, I must say that this is a professional magazine.

I enjoy reading every issue, including the advertisements.

JOSEPH YU, OALA HAMILTON

Our association can be compared to a hardy oak tree. Our roots—laid down by the founders of the OALA more than forty years ago—are solid, and our sturdy trunk holds up a wide, over-arching canopy. Our bylaws and regulations provide a secure structural framework for our association to flourish and be represented by members from a wide diversity of specialties, which collectively represent landscape architecture.

Our profession is properly poised to meet the challenges of our present global economic crisis. These emanate from various circumstances, but I believe the most lasting impact will be led by landscape architects in prominent roles developing green, sustainable solutions for our communities.

The demographics of the OALA are set to change over the next few years as many of our leaders retire from active work. This will provide new opportunities for our associates and new members to thrive in their careers. I am optimistic that the future of the OALA is bright. Our core is strong, our growth is vigorous, and the call for our profession to take up leadership roles in strategic planning and design has never been so clear.

This is my last Ground message as OALA President. It has been an honour to serve you as President during the past two years. I encourage each member to take the opportunity to participate on Council. It is a rewarding experience to work and learn with our colleagues and to understand and resolve the issues that confront our association on a regular basis.

I look forward to meeting many of you at the 2009 CSLA/AAPC Congress, in Toronto, hosted by the OALA. The theme, PERSPECTIVES – 360˚ on 75, will celebrate the impact of the Canadian Society of Landscape Architects over the past seventy-five years.

Make your plans to participate, from August 13-15, 2009!

ARNIS BUDREVICS, OALA PRESIDENT PRESIDENT@OALA.CA

Up Front

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Some European cities, such as Rotterdam, are rejuvenating their tower neighbourhoods.

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Graeme Stewart A typical tower landscape in Toronto, Weston Road

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Jesse Colin Jackson

Up Front: Information on the Ground

URBAN RENEWAL

towers in a park

The reigning orthodoxy identifies Toronto’s extensive ravine system as the feature that makes the city unique. Graeme Stewart of E.R.A. Architects Inc. posits a radical, mythbusting alternative. According to Stewart, what makes Toronto distinctive is that it is a city of towers. With more than 1,000 high-rise concrete residential buildings (approximately 25 percent of the city’s housing stock), the Toronto area contains North America’s second-highest concentration of high-rise buildings, many of them built in the 1960s and 1970s. A further unique feature is that, unlike most other cities, these modern towers are dotted in high-density pockets throughout the city and its suburbs, not just downtown: “Toronto may be the only city where the juxtaposition of bungalows and concrete towers is the typical landscape,” says Stewart.

Due to zoning and density bylaws, these towers are often surrounded by large areas of open space, “a huge resource,” says Stewart. However, just as many of the buildings are neglected and falling into disrepair, so too is the open space often underutilized and uninviting, largely relegated to surface parking and in many cases surrounded by chain-link fence.

Touring a quintessential tower landscape in Toronto near Kipling and Steeles on a bleak November day with Stewart, these lost opportunities are brought into sharp focus. We’re in an area that’s home to 13,000 people (a population density comparable to the third largest city in Manitoba), yet we see no one. We’re standing on what was once some of the best farmland in the province, yet nothing

other than grass is actually growing. We’re overlooking the Humber River, with one of the best panoramic views the city has to offer, yet to access the nature trails we have to clamber over a breach in the fence. The original design intent of this particular housing model—”towers in a park,” says Stewart—is clear, yet something has just as clearly gone wrong.

Stewart is on a mission to rejuvenate the city’s tower neighbourhoods and, for him, the landscape is crucial. “Landscapebased changes could have a huge impact,” he enthuses, listing everything from simple fixes (“removing some fences”) to more committed research studies (“solar analyses of sites to see where community gardens could go”). “So much of this is about engaging open space,” he says.

Stewart has championed renewal schemes that include building overcladding (currently under development at the University of Toronto by Professor Ted Kesik), so that buildings would become far more energy efficient, saving money and reducing their ecological footprint. His focus doesn’t end with architectural renovation, however. He believes it is possible to create sustainable and vibrant neighbourhoods using ideas like infill housing, district energy, new community facilities, transit, pedestrian, and cycling connections, and urban agriculture. Integrated into the emerging regional transit, growth, and climate change plans, and fueled by the remarkable cultural diversity within these neighbourhoods, Stewart sees the rejuvenated tower communities as a type of neighbourhood that will be uniquely Torontonian. The challenge for local designers is to create new, vibrant, and dynamic “complete communities” that respect the historical characteristics of the concrete towers in the park and respond to local needs. These communities can connect residents to the landscape while remaining affordable and diverse.

Up Front

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In recent months, the goal of rejuvenating Toronto’s tower neighbourhoods has gained a lot of traction. Following an international tour of tower refurbishment sites, Stewart was enlisted by the city to publish an “Opportunity Book,” and the city has branded the project “Mayor’s Tower Renewal.” In September, City Council voted to re-examine its policies surrounding apartment neighbourhoods in an effort to help them become more ecologically, socially, culturally, and economically sustainable. An office—Tower Renewal Office—has been established to coordinate the initiative and is to report back to Council in March 2009. The province’s Climate Change Secretariat is on board.

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SOIL

valuing the rhizosphere

“As far as I’m concerned, if we’re going to talk about trees,” says Michael OrmstonHolloway, “the first thing we need to talk about is soil.” Trees are of passionate interest to Ormston-Holloway, a recent graduate of the University of Toronto Master’s of Landscape Architecture program now working at Michael Van Valkenburgh Associates in New York.

Prior to studying landscape architecture, he obtained a B.Sc. in Plant Biology and a professional M.Sc. in Forest Ecology: “I thought that I was studying forests, but much to my surprise, my M.Sc. in Forest Ecology was virtually a degree in soil science.” Now, he’s taking that same message about the importance of soils to his work at a landscape architecture firm: “As landscape architects, we need to direct our attention below ground.”

Landscape architects are currently providing input into some of the open space resource systems associated with Toronto’s concrete towers. Brendan Stewart, an MLA student at the University of California, Berkeley, is developing landscape strategies for tower renewal in his thesis. “Engaging landscape architects in this project is fundamental,” says Graeme Stewart, “and they need to be involved from the beginning. There is tremendous opportunity for innovation.”

Ormston-Holloway believes that, for too long, landscape architecture has focussed on the two-dimensional linear surface of the earth—”this is the dimension we activate in our work,” he says.

“And we also leap into the fourth dimension of time, with our phasing strategies, for example.” What’s often missing, he believes, is the third dimension—the rhizosphere. “This is the medium of growth,” he stresses, “and yet soil is probably the most under-appreciated natural resource in the developed world.”

For more information on the tower renewal project, visit www.towerrenewal.ca and www.towerrenewal.com.

TEXT BY LORRAINE JOHNSON AND NETAMI STUART, BOTH OF WHOM ARE MEMBERS OF THE GROUND EDITORIAL BOARD.

While he’s keenly interested in “getting people to look down, to ask themselves, ‘what am I walking on,’” OrmstonHolloway is also looking up, to the trees.

For his work with Michael Van Valkenburgh Associates on the Lower Don Lands in Toronto (“yes,” he says, “it’s a little strange that I’ve moved to New York to work on a project in Toronto”), he’s involved with the urban forestry issues on the site, particularly as they relate to biodiversity. “We probably all agree that we don’t need 0C

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any more honey locusts in Toronto,” he says with a laugh. “There’s a much wider palette we could be using.”

Ormston-Holloway suggests that there is a simple question landscape architects should ask themselves, and it’s a question that might seem somewhat odd coming from someone steeped in forestry: “We can put a tree in the ground, but why are we putting it there?” He suggests that once people start considering the “why” question and making choices based on a wider range of goals—say, choosing a species not just for the aesthetics, but also for wildlife, for example—the benefits will magnify: “The idea of biomagnification of benefits is just a fancy way of expressing the basic idea of ecology,” he notes.

“Everything is connected.”

TEXT BY LORRAINE JOHNSON, EDITOR OF GROUND AND A BOARD MEMBER OF LEAF (LOCAL ENHANCEMENT AND APPRECIATION OF FORESTS).

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Currently underutilized green spaces surrounding Toronto's residential towers represent a huge opportunity.

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E.R.A. Architects Inc. Michael Ormston-Holloway’s thesis poster, “Urban Ecologies as Landscape Infrastructure”

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Michael Ormston-Holloway

Up Front

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SCHOOL GROUNDS

designing children’s spaces

The non-profit organization Evergreen has been at the forefront of school ground greening in Canada. Through research reports, grant programs, a regular newsletter, and the publication of numerous how-to manuals and web resources, Evergreen has both promoted and supported the development of outdoor learning grounds for close to two decades.

According to Cam Collyer, Evergreen’s Director of Learning Grounds, the organization has been involved with approximately 3,000 schools over the years.

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dramatically in just one generation—as Collyer put it in his keynote presentation, “we’re witnessing the disappearance of free roaming in childhood.”

As children’s experience of the outdoors shrinks, the school ground environment takes on added importance as a site of engagement with nature and with play.

“We’re at a moment in time when the stakes are getting higher,” asserted Collyer. “This is a public health issue.”

At a recent conference in Toronto, “All Hands in the Dirt,” Evergreen brought together an international and local roster of speakers—including landscape architect Margery Winkler of Ryerson University and University of Guelph professor Nate Perkins—to explore recent research related to the school ground environment and to look at design issues in particular.

One of the ironies of framing school ground design in terms of health is that this can, in some circumstances, lead to poorly designed school ground environments, according to many speakers at the conference. Citing the work of Danish designer Helle Nebelong, Collyer suggested that the simplification and standardization of outdoor environments can have negative implications for children: “It doesn’t prepare them for the world.” Showing a slide of a rock mountain surrounded by asphalt in Oslo—and admitting that such a play structure “pushes the boundaries for most North Americans”—Collyer proposed a rethinking of physical development: “Put risk in front of children and they learn.” That is, although it may seem counterintuitive, some measure of risk can actually help children learn to negotiate and avoid even bigger risks. “We’re curious beings,” emphasized Collyer. “Kids need to be enticed and provoked and excited by their physical environment.” He pointed to the work of Berlin landscape architect Oliver Ginsberg, who builds on research done by the insurance industry, which found that there are in fact fewer accidents in “adventure playgrounds.” Likewise, presenter Sally Kotsopoulos had a blunt warning about the notion of risk that has dominated school ground design: “If you don’t get hurt when

A thread tying all the presentations together and adding a measure of urgency to school ground design work was the notion that childhood has changed. No longer do parents send kids outside to play with an offhand “be home for dinner.” As recent research in Sheffield, England, has documented, the range of unsupervised wandering in children’s lives has decreased

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you’re four or five, man are you going to get hurt when you’re twenty-five!”

Robin Moore, one of the world’s leading experts on kids and outdoor environments, stressed that while children now have “too much structure in their lives,” he wasn’t advocating doing away with it altogether: “Clarity of structure is important, but outdoor environments should have structure and fluidity, so kids have options for informal experience—the first step to curiosity and wonder.” As examples, he pointed to the importance of designs that incorporate curved pathways (“so kids have motivation to move”), variations in topography (“a little hill goes a long way”), and food plants (“landscapes that are pickable, tasteable, and suckable!”).

Other design ideas included diversifying surfaces, and incorporating multiple levels and small sanctuaries—“hideouts for kids, places adults can’t get to, are crucial.”

Putting forth many practical ideas, the conference, at heart, had a hopeful message.

As Collyer put it, “when you diversify the landscape, you erase boredom.”

For more information on recent research into designing outdoor environments for children, see www.childrenandnature.org or www.evergreen.ca.

TEXT BY LORRAINE JOHNSON, EDITOR OF GROUND.

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Creative features engage children at Coombes elementary school in Reading, England.

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Cam Collyer Rock mountain at Manglerud elementary school in Oslo

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Cam Collyer The Niagara Escarpment Commission recently approved Visual Assessment Guidelines outlining standards for development.

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Niagara Escarpment Commission

Up Front

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THE NIAGARA ESCARPMENT

visual assessment guidelines

Designated a UNESCO World Biosphere Reserve in 1990, Ontario’s Niagara Escarpment is an ancient landform recognized for its diverse ecosystems, rich agricultural lands, breathtaking scenic vistas, and exceptional outdoor recreational offerings such as hiking and skiing.

Development in the Niagara Escarpment Biosphere Reserve is guided by the Niagara Escarpment Plan (NEP), Canada’s first large-scale environmental land use plan. The NEP sets out land use designations, related permitted uses, and development criteria to assess these uses. It also provides the framework for a string of more than 130 existing and proposed parks and open spaces linked by the Bruce Trail, Canada’s oldest and longest continuous footpath.

The Niagara Escarpment Commission (NEC), an agency of Ontario’s Ministry of Natural Resources, is the land use planning agency responsible for overseeing development in the Niagara Escarpment Plan Area, which is a protected area under provincial legislation (The Niagara Escarpment Planning and Development Act—NEPDA).

The NEP is administered through a Development Permit system. The assessment of land use change requires compliance with the environmental and visual policies of the Plan and Act. Purpose of Visual Assessment Guidelines The Niagara Escarpment Commission’s planning process incorporates visual and scenic considerations; impacts on scenic vistas and landscape quality are considered alongside a range of other potential environmental impacts. Visual assessment studies help NEC planning staff identify and evaluate whether a development proposal is compatible with the NEPDA and the NEP. In July of 2008 the NEC approved Visual Assessment Guidelines outlining standards for the preparation of studies, when required, in support of a proposed development.

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Process The first step in the process is to identify any concerns over a development proposal’s potential visual impact on the Escarpment landscape. A development proposal may include residential and agricultural buildings, telecommunication towers, recreational facilities, residential wind turbines, and utilities. The proposal may also include site alteration such as the removal of vegetation within hedgerows, tree stands, or parts of wooded areas.

Where visual impact is of concern, the applicant is advised that a Visual Assessment Study is required and recommended study methods are outlined in keeping with the type of proposed development. A Visual Assessment Study first establishes a baseline for the existing conditions, and identifies the physical changes in an accurate and objective manner.

Subsequently, the impact of the change on the Escarpment landscape and visual resources is assessed.

The guidelines identify a series of standard methods applied in preparing a Visual Assessment Study. All of the methods address the visibility of proposed built form when viewed from public roads, public lands, and the Bruce Trail. Public lands also include public waterways such as Georgian Bay and Lake Ontario.

The methods include: • Digital viewshed mapping to objectively and accurately identify where proposed structures or built form would be visible from public roads, public lands, and the Bruce Trail. The specifics of a proposal will dictate the distance out from the structure to be mapped—generally five kilometres.

• Where the viewshed model indicates the development would be visible, specific viewpoints/viewsheds are selected for additional investigation.

This study component may include line of sight cross-sections, photographic simulations, and detailed viewshed mapping.

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Not all of the investigative methods outlined in the guidelines would necessarily be required for a given study.

Assessing Impact on the Escarpment Landscape This part of a study addresses the impact of the physical changes on the visual, landscape, and scenic resources of the Escarpment environment. As the character of the landscape varies greatly throughout the NEP, the impact of development must be assessed in the context of the particular landscape. The assessment must ensure the proposal is in keeping with the NEPDA, NEP, and approved policy papers as well as identify whether or not the development would alter the results reported in previous studies.

Review Review of a Visual Assessment Study may result in the NEC requesting that the proponent alter the proposal to minimize or mitigate impact. If the proposal’s resulting impact is deemed acceptable to the NEC, the proposal would be recommended for approval. Critical details derived from the Visual Assessment Study would be identified in the approval and/or implementation process that follows.

The NEC’s Visual Assessment Guidelines and supplementary policy reports are available at www.escarpment.org.

TEXT BY LISA LAFLAMME, OALA, A LANDSCAPE ARCHITECT WITH THE NIAGARA ESCARPMENT COMMISSION.

Up Front

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TREES

breeding elm's future

Sometimes called a “dating service for lonely elms,” sometimes known by the affectionate acronym ERP, the Elm Recovery Project at the University of Guelph Arboretum may have some playful names, but its purpose is deeply serious.

Officially launched in 1998, the goal of the Elm Recovery Project is to return the beloved and iconic American elm to the landscape. This stately, vase-shaped tree was virtually wiped out by Dutch elm disease. Although young elms still grace streets, backyards, and farmer’s fields, most of them succumb to the disease when they reach fifteen to forty years of age. However, there are rare survivors, and it is these mature, relatively diseasetolerant giants that hold the promise of elm recovery.

“These old trees seem to have the ability to compartmentalize the disease successfully, in effect to quarantine the disease in just a few branches, and keep growing,” says Sean Fox, horticulturist at the arboretum. Fox is leading the project, following the death of ERP’s founder, Henry Kock, in 2005. “Henry had this idea,” says Fox. “He wondered why some elms were still alive.” Kock put out the word that he was

looking for mature survivors and received reports of 1,500 trees scattered throughout the province, from Windsor to the Quebec border and as far north as Sault St. Marie.

Over a period of six years, Kock and Fox visited 600 of the mature elms and collected cuttings from approximately 300 hardy specimens. The cuttings have been grafted on rootstock from a mature, healthy elm growing in Guelph. When the grafts are between five and seven years old, they are injected with Dutch elm disease—sometimes repeatedly—to see how they respond. “It’s a miracle to see them survive after being injected three years in a row,” enthuses Fox. He adds that he doubts any elms are truly immune to the disease, “rather, some trees just tolerate it due to their unique genetic code.”

Once the seedlings are screened for tolerance, the hardy specimens are candidates for ERP’s breeding orchard at the University of Guelph Arboretum, where proven disease-tolerant trees will eventually be bred with each other. “The breeding program will bring the best of the best together, so their offspring will, we hope, be able to tolerate whatever nature throws at them.” Fox notes that it is this strategy of seed propagation, rather than cloning, that makes ERP unique: the Dutch elm disease-tolerant cultivars available in the U.S., such as Jefferson and Princeton, for example, are clones, making them vulnerable should the disease mutate. “We’re trying to make the odds as good as possible,” says Fox of the breeding program, which is much more time-consuming than cloning. “Basically, we’re just doing what nature does—but we’re speeding it up by bringing isolated survivors together.”

“It might take us fifty or sixty years to get a second generation of seeds from the breeding orchard trees,” says Fox, clearly a very patient fellow. “I probably won’t be around...” But he’s not only patient, he’s cheerful: “Can you imagine what an amazing sight those elms will be?!”

TEXT BY LORRAINE JOHNSON, EDITOR OF GROUND. TO SUPPORT THE ELM RECOVERY PROJECT WITH A TAX-DEDUCTIBLE DONATION, VISIT WWW.UOGUELPH.CA/ARBORETUM/.

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POOLS

a freshwater alternative

The growing consumer demand for nonchlorinated swimming pools has spurred the development of alternatives such as saltwater and ozone pool systems. Now, natural swimming pools (NSPs)—a freshwater alternative—are surfacing across North America. This trend follows on the heels of Europe and Great Britain where, since the 1980s, thousands have been built.

Conventional pools rely on chlorine and other chemicals to maintain sterile, algaefree water, while NSPs are anything but sterile. They are living aquatic ecosystems, designed to look and function like a natural pond, with lush living plant filters—the signature feature—surrounding an open swim zone. The plant filters, in turn, provide a habitat for birds, dragonflies, frogs, turtles, newts, and a host of other fauna.

Science in a Nutshell Natural swimming pools rely primarily on complex natural microbial processes to purify and clarify the water. They incorporate rock filters and other bio-media where beneficial bacteria can colonize and perform the necessary cleansing action. These bacteria are responsible for the aerobic decomposition of organic matter accumulating in the system, thereby releasing nutrient compounds sustaining zooplankton—a natural algae predator—and the plant filters.

The plant filters are particularly effective at taking up nutrients, which further stymies algae growth. The bacteria are oxygen dependent, which dictates the need for a waterfall and submergent oxygenating plants. Since the bacteria do not remove potentially harmful pathogens such as ecoli, UV filters are generally recommended as a non-chemical water treatment.

Up Front

Design and Construction NSPs are typically designed to look like a natural pond, with curved organic lines, natural stone edges, and substantial plantings both in the “filter” area (which is separate from the swimming area) and around the perimeter to reinforce the naturalistic appearance. They can also be designed to resemble a conventional pool, with the plant filters and biofilter located in an area away from the pool. They can be constructed to any size, though a swim zone roughly the size of a typical residential pool will require 30-50 percent more space to account for the plant filters.

Like any pool, the construction of an NSP begins with a hole in the ground. The similarities end there. The basin is excavated with sloped walls to a depth of 7-8 feet, with a 3-foot-wide shelf halfway down. The shelf serves as a base for a 3- to 4-foot high retaining wall constructed of rot-resistant wood, which separates the plant filters from the swim zone. The basin is lined with a black, “fish-friendly” rubber liner. Perforated pipes are placed behind the retaining wall, and covered with layers of graded granite river rock—a highly effective bio-media readily colonized by beneficial bacteria.

The rock filters are capped with pea stone, which is used as a substrate for a wide range of native emergent and submergent aquatic plantings. The perforated pipes are connected to one of two circulation systems.

Water pumped through the plant and rock filters is discharged back to the bottom of the pond via a return pipe.

The second circulation system pulls water through one or two skimmers located along the shoreline to filter out larger floating particles, dead insects, and leaves. Water drawn through the skimmers passes through the UV filter before emptying into a biofilter— essentially a plastic box filled with bacterialaden bio-media—before cascading over the top of the waterfall.

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Keeping it Clean Natural swimming pools are not maintenance-free and bacteria must be added on an annual basis. The pool bottom should be vacuumed every week or two to prevent sediment build-up. Skimmers should be cleaned every couple of days and leaf nets may be required in the fall if trees surround the pool. Plant filters may require thinning every few years. On the plus side, NSPs do not have to be drained for the winter.

It is possible to heat a natural swimming pool, but only if you are prepared to monitor water temperature judiciously. A heater can help extend the swimming season in the spring and fall, by holding temperatures at no more than 70 degrees Fahrenheit. In fact, by heating in the early spring, bacteria that would otherwise stay dormant until the water temperature reaches 65 degrees Fahrenheit can be activated to avoid cold water algae blooms that tend to occur just after the ice has melted. However, come the summer months, the water temperature will rise well above the 70-degreeFahrenheit threshold, and adding more heat would be reckless; algae thrive in warm water and aquatic plants hate it.

For the most part, NSPs typically cost about the same as a conventional pool of a similar size, though features such as elaborate waterfalls can, not surprisingly, escalate costs.

Natural swimming pools are not for everyone. If the idea of swimming in a pond or lake is a turn off, or if the thought of swimming next to plants is unnerving, or if you want a heated pool, other swimming pool options should be considered. Yet for the right homeowner on the right property, natural swimming pools can be a beautiful, refreshing, ecologically sensible alternative to a conventional pool.

TEXT BY JEAN-MARC DAIGLE, OALA, PRESIDENT OF GENUS LOCI ECOLOGICAL LANDSCAPES INC., A SCHOMBERG-BASED DESIGN/BUILD FIRM THAT CONSTRUCTS NATURAL SWIMMING POOLS.

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RE-USE

urban tree salvage

Although landscape architects often strive to save the existing trees on a project site, it is not always feasible. Many of these removed trees become mulch or firewood, a fact that Urban Tree Salvage, a unique Scarborough company, is trying to change. According to their website, approximately nine thousand trees are removed from the Greater Toronto Area each year due to storm damage, age, insect and disease problems, and construction projects. That’s a lot of trees!

In operation since 2005, Urban Tree Salvage (UTS) has re-routed thousands of trees from chippers and landfill into creative furniture and accessories. The company also offers a wide range of lumber, some with very unusual grains and interesting origins. They make candle holders, for instance, from old-growth pine which was salvaged from Toronto’s historic Queen’s Wharf (circa 1830).

There is also the option of ordering items from the very trees that you remove from your site. Whether the final product is made by UTS, or you produce it elsewhere from the lumber milled by UTS, having those removed trees reappear as benches, bollards, or fence components would be a unique site feature.

Visit the company’s website at www.urbantreesalvage.com for more details on UTS’s lumber and built products.

TEXT BY HELEN POWERS, OALA, A FORMER MEMBER OF THE GROUND EDITORIAL BOARD.

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Henry Kock, ERP’s founder, with a mature elm

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Sean Fox Natural swimming pools are living aquatic ecosystems that function like natural ponds.

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Genus Loci Ecological Landscapes Inc. Old-growth pine bench made from recycled wood

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Urban Tree Salvage

Tree Myths and Tree Debates

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Tree Myths and Tree Debates Experts dish the dirt on common misconceptions about trees, and dive into debates about controversial practices

Myth: When planting a tree, it is fine to leave the burlap tied around the root ball because it will rot away.

In response to this common misconception, certified arborist Todd Irvine of Bruce Tree Expert Company of Toronto offers an emphatic “Arghh!!” While he agrees that the burlap will rot, he adds “yes, in years. Why would you not do everything in your power to give the tree a fighting chance?!” The problem with leaving the burlap on is that small fibrous roots can not push through it. As well, notes Irvine, “burlap acts as a moisture wick, pulling water away from the roots just when they need it the most, post-planting.” Irvine suggests that an even greater problem is the tie used to hold the burlap in place: “If left on, it can girdle and kill the tree in a matter of years.”

Instead, Irvine says that all ropes and ties should be removed, the wires of the basket bent back and cut off, and as much of the burlap removed as possible: “As an arborist, I would never leave that stuff on.”

Myth: Trees are the lungs of the planet.

It may work as a metaphor, capturing the public’s attention and reinforcing the notion that trees are a good thing, but as science, it’s a somewhat slippery analogy.

TEXT BY JOCELYN HIRTES, ASSOCIATE MEMBER, OALA, AND LORRAINE JOHNSON

Consider what lungs do: in respiration, we breathe in oxygen and breathe out carbon dioxide. Yet when people use the “lung” metaphor for trees, what they’re usually referring to is the idea that trees take in carbon dioxide from the air and release oxygen—in other words, the exact reverse of what human lungs do.

It gets even more complicated, though, because the oxygen-producing capability of trees is just one side of the equation. Trees take in carbon dioxide and release oxygen when they’re photosynthesizing during the day, but at night, the reverse occurs and trees take in oxygen and release carbon dioxide.

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Planted in 1701, this eastern hemlock lived for 295 years.

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Henry Kortekaas Tree ties and stakes can cause damage to trees.

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LEAF (Local Enhancement and Appreciation of Forests) Trees slated for removal can sometimes be retained, depending on location and other factors.

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Lorraine Johnson

However, this is not to say that trees contribute to the build-up of carbon dioxide in the atmosphere. On a global scale, the amount of carbon dioxide absorbed by plant matter is double the amount of carbon dioxide plants release through respiration.

So, yes, trees produce oxygen, but the “lung” metaphor is a bit misleading.

Tree Myths and Tree Debates

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Debate: Due to the effects of climate change, we should be planting southern species now.

John Ambrose, a conservation biologist based in Guelph, takes a broader view: “The biggest challenge for trees in southern Ontario is the disconnectedness and fragmentation of the forest matrix.”

Quite simply, tree populations are isolated from each other, existing in pockets separated by urban development and agriculture.

“What we should be doing is looking for ways to reconnect that fragmented network, to restore the matrix, so that seeds of the best adapted trees within natural forest populations can move on their own across the landscape in response to climate change.

In addition, increasing the percentage of forest cover helps moderate climatic extremes.”

However, Ian Bruce, founder and senior consultant with Bruce Tree Expert Company of Toronto, says, “I always encourage clients to provide some form of supplemental support when planting large trees. This is especially important on open windy sites, and/or in cases where the tree has a large, well-developed crown and a limited sized root ball. The number one reason is to anchor the tree long enough for the fragile, fine roots to grow out into the soil, to replace those lost when the tree was moved.”

Bruce stresses, though, that once the stakes have served this function—usually after one or two years—they should be removed. He also cautions against staking trees so tightly that they can’t bend at all in the wind: “Trees are perpetually self-engineering. They expend energy where they need to. So if they’re allowed to bend a bit—say, if there’s an inch of play between the tie and the trunk—this strengthens the trunk. Biomechanically, the tree responds to the need to support itself by developing a strong trunk in response to the movement. Allowance for natural trunk movement will result in increased diameter development and a more noticeably uniform taper from the ground up to the first main branches. “

Debate: To stake or not to stake?

According to Richard Ubbens, City Forester, Toronto, “Staking is absolutely not necessary; it’s a big mistake we have all been making for decades.” Ubbens notes that “where you have stakes, you see lots of issues caused by girdling. And you are not seeing the root flare and you are not seeing the stem diameter growth because stakes are restricting the natural hormonal response to wind. The wind moving the stem causes a specific hormone to stimulate stem growth and anchor root development and root flare—a key component of getting trees established.”

In response to the idea that on windy sites where the soil is new and uncompacted, trees need to be stabilized by staking, Ubbens says: “As long as you make the tree pit wide enough when you dig the hole, staking is not necessary; just firm in the soil at the bottom side of the root ball. Then all the material that goes in beside the root ball does not need to be so compacted. We always emphasize the importance of fracturing the parent soil.

If you do this properly, you will have roots growing into the undisturbed soil within a month. There is no issue with stability.”

With regards to bare root trees, Ubbens says: “We sometimes use a two by two wood stake with a biodegradable nylon tie that breaks down in UV light and will be gone within a year. Even then, it’s only if a bare root tree comes with few roots. Nine out of ten bare root trees don’t even need staking.”

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Myth: All dead trees should be cut down.

For many people, the idea of leaving a dead tree standing verges on heresy. It goes against conventional concepts of aesthetics and safety, for a start. But Philip van Wassenaer, founder and owner of Urban Forest Innovations Inc. based in Mississauga, argues that dead tree management conventions need to be challenged: “We

Tree Myths and Tree Debates

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Acknowledging that shade will limit the effectiveness of solar panels, Pickering sees a crucial role for landscape architects at the design stage: “Landscape architects need to think about how landscapes can be designed in a way that integrates the benefits of trees and potential solar installation.” The solution is not fewer trees, says Pickering, but strategic placement of trees through the design lens of solar opportunities.

need to turn North American perceptions around.” If that’s too much of a stretch, he offers a qualification: “I’m not saying that we should leave big old nasty dead silver maples hanging over Yonge Street, just that there are lots of appropriate places— ravines and extensive back yards, for example—where we can safely leave dead trees.”

Wassenaer urges consideration of the ecological importance of standing dead trees (also known as snags) and trees with dead parts or “defects.” “They provide unique habitat for organisms that depend on them and that will not exist without them. Old and dead trees act as a sort of ‘ark of biodiversity’ that allows certain species to persist over time.” He points to research being done in Great Britain by Keith Alexander and the work of Neville Fay of the Ancient Tree Forum. In Britain, close to 1,800 species (approximately 6 percent of the total known fauna of Britain) are dependent on the process of wood decay in trees and shrubs.

Myth: Mulch should be mounded up around the base of trees.

Incorrect mulching practices abound—examples can be found everywhere—but a particular insult to trees is the practice known as “volcano mulching.” “This is when people pile new mulch around the base of trees and up the trunk, so the tree looks like it’s erupting from the mulch,” explains certified arborist Todd Irvine of Bruce Tree Expert Company of Toronto. “It’s based on a complete misunderstanding of trees and root growth.”

To the question of safety, van Wassenaer responds: “A tree is not a hazard if there is no target.” Thus, location is key—close proximity to buildings and public routes is out, for example.

Likewise, certain tree species are more appropriate for retention than others. “Oaks, sugar maples, and white pines, for example, will, in general, stand stable for a long time even when dead,” he says, “as long as they didn’t die because of significant decay or root problems.”

One of the problems with volcano mulching is that it threatens the health of a tree’s bark: “The mulch traps moisture against the bark—it can rot the bark right off the tree,” says Irvine.

Another problem is that it inhibits gas exchange in the bark and the root ball.

Instead, Irvine recommends that a 5- to 10-centimetre layer of composted wood mulch be applied evenly for at least a 1metre radius from the trunk of young trees and out to the drip line of larger established trees. The layer of mulch should taper down to meet the original soil a couple of centimetres before reaching the trunk.

Wassenaer suggests that for appropriate dead trees in appropriate locations, branches could be removed, leaving a sturdy trunk.

“Without the branches, there won’t be any lateral forces acting on the tree—only gravity—and inertia will keep it standing.”

As for how people react to the idea, he acknowledges that while he advocates for leaving dead trees standing in certain situations, “this is not yet considered normal behaviour.”

Myth: Trees inevitably interfere with solar panels.

Mary Pickering, Acting Executive Director of the Toronto Atmospheric Fund, is concerned that two environmental strategies to combat climate change—planting/preserving trees and increased use of solar panels—are sometimes pitted against each other. “We certainly don’t want solar panels to be another excuse for people to say that ‘trees are in the way.’ When we hear requests to cut down trees to put up solar panels, we just shriek! That’s because a mature tree shading a house might be providing greater net emissions reduction benefit—through reduced need for air conditioning—than solar panels could.”

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Tree Myths and Tree Debates

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Myth: The majority of tree roots go down deep.

We should all be sent back to school to re-draft those drawings of trees we did as children—those lollipops sticking out of the ground, with not a root in sight. (If we did draw the roots, it was probably just one spindly anchor going down deep in the ground.)

“The whole idea that all roots go down deep is completely false,” says Todd Irvine. “The majority of a tree’s roots are in the top foot or two of soil.” Instead of growing vertically, extending down, most roots form a huge horizontal network that extends outwards, well beyond the drip line. “Roots form a mat just below the soil’s surface,” says Irvine, noting that in ideal situations an open-grown tree could have a root zone that extends two or three times the radius of the drip line.

Thus, any excavation done in that top foot or two of soil must be done carefully, to avoid damaging the extensive network of roots.

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Volcano mulching is bad for trees.

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Lorraine Johnson A cluster of installed trees and shrubs at Fresh Kills landfill, eight years after installation

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Steven Handel

Myth: Trees cannot be planted in decommissioned, capped landfills because their roots will puncture the cap.

When Dr. Steven Handel, Director of the Center for Urban Restoration Ecology and a professor of plant ecology at Rutgers, was asked by the New York City Sanitation Department to restore a decommissioned landfill, he proposed planting the site with native trees. The response from the civil engineers was immediate and emphatic: trees could not be used because their roots would puncture the protective clay or geomembrane cap, allowing water to percolate down through the garbage and contaminate the groundwater. “These engineers were highly educated but they were not trained in biology,” says Handel. “They weren’t convinced that the roots would stay in the soil above the cap.”

And so Handel embarked on a three-year experiment. He planted one hundred trees and shrubs on a capped landfill and one hundred on an adjacent site as a control. When he dug up the roots a few years later, he found that the roots of the control trees went down relatively deep, but the roots on the landfill site hit the cap and then went horizontal, staying on top of the cap.

“The truth is that roots are smart,” says Handel. “They move to the zone of least resistance where there’s moisture, oxygen, and their needs are met.”

The legacy of Handel’s research is that, in the US, trees are now regularly planted as part of the restorations of decommissioned landfills. And word is spreading to Canada. When Handel attended a conference in Guelph last year, where a plan for turning a decommissioned landfill into a pollination park was discussed, he made a compelling case that trees have a role to play: “It’s possible to have native trees all over these old landfill sites. They will not interfere with engineering goals; in fact, they complement the goal of lessening leachate by transpiring water.”

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JOCELYN HIRTES, ASSOCIATE MEMBER, OALA, IS A CERTIFIED ARBORIST AND A MEMBER OF THE GROUND EDITORIAL BOARD.

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LORRAINE JOHNSON IS THE AUTHOR OF THE NEW ONTARIO NATURALIZED GARDEN.

Genes Matter

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TEXT BY BARB BOYSEN

Genes Matter Sourcing appropriate trees to ensure success

Trees are alive—seems obvious. But then why are they often treated like fences or lamp posts? Trees have needs that are largely under genetic control. What this means is, pay attention or suffer the consequences: diseased, strangled, abused, not-meeting-their-potential, dying-before-their-time, waste-of-money trees.

Genetically controlled needs of trees vary by species, by source of seed, and by individual responses to climate, soils, drainage, and light. As well, trees have evolved as part of a system of give-andtake with insects, diseases, other animals, and plants. So, if both the tree’s individual and system needs are met, it will thrive, giving us amazing benefits over decades, even centuries, and even in cities.

Not recognizing this genetic complexity, or proceeding in spite of it, has costly consequences, which accumulate in tending or in replanting poorly planted trees. There is also a cost in terms of not meeting objectives such as beauty, shade, windbreak, etc. Perhaps we don’t articulate what we expect from trees or consider how best to achieve our goals. Maybe it’s too much about growing and planting and not enough about what and where we’re growing and planting.

For too long, people have brought in plant material from distant and different places, often ignoring the local forest wealth and the value of its local adaptedness. At first, maybe this didn’t do a lot of harm.

But who foresaw the erosion of the natural forests in and out of cities? Who knew we’d face the chestnut blight, Dutch elm disease, and now Asian long horned beetle and emerald ash borer? Who knew Norway maples were so susceptible to tar spot, would threaten our ravines with erosion, and then not even thrive for more than sixty years? Who knew we’d remove the topsoil and compact the rest?

We need to get back to the basics—to understand basic tree functions over long time periods. We need to understand how to marry the climate and site to the tree and to our objectives, and then make aesthetic choices. And we need to ensure diversity with enough variation to make sure the system as a whole keeps functioning, because the stakes are getting higher and the pressures greater due to the scary and costly effects of invasive insects, diseases, and climate change.

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Many of Ontario’s tree species are genetically adapted to the climate conditions of their local area.

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Forest Gene Conservation Association

If there was ever a time to start doing things right, it’s now. So why are we still planting too few species, mostly exotics, of unknown genetic provenance, or too many clones, in places where no one should expect any tree to thrive? Is it client ignorance, or lack of planning, or short-term economics, or all of the above and more? What are the barriers to doing the “right thing,” and how can we work together to remove these barriers?

Genes Matter

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Unfortunately, genetics, the seed source or provenance of a tree, is a largely ignored part of tree planting. Many species are native throughout large areas, and therefore throughout many different climates. In southern Ontario alone, our growing season can vary from 239 days in Windsor to 215 days in Ottawa to 185 days in Algonquin Park. Summer and winter temperatures and precipitation can also vary greatly.

Scientists have discovered that many species have evolved to become genetically adapted to the climate conditions of their local area. This means, for example, that a red oak which evolved over many generations in the highlands of Algonquin Park is genetically different in its adaptation to climate from a red oak that evolved in Toronto. When a red oak is moved to a different set of conditions, even within its “native” range, it may suffer from spring or fall frosts, moisture or heat stress, and snow or cold damage. These stresses can kill the tree or result in reduced growth, or reduced vigour, which then makes the tree more susceptible to insect or disease damage. However, we don’t know the degree to which seed source matters for most species, and cutbacks in environmental research mean that we likely won’t gain this knowledge any time soon. But we do know that considerable geographic and genetic variation exists for many of Ontario’s tree and shrub species.

So knowing that for some species variation does matter, we can act to limit both the ecological and economic risks by matching the conditions of the source of the seed to the conditions of the planting site. The Province of Ontario has used this principle to implement a policy of tree seed zones that forest companies must respect when collecting seed and planting trees on Crown land.

While mandated by the Province for the forestry industry, seed source is largely ignored in the landscape industry. And it is in this realm that landscape architects have an important role to play.

The Forest Gene Conservation Association has a program to help practitioners (consumers and professionals alike) get the most appropriate trees for their needs. It is a voluntary seed and stock certification program. Members of the private sector—from seed collectors to seed processors to growers—can participate by registering the source of their plant material and subjecting themselves to inspections and audits. This stock will then be eligible to be marketed as “Ontario’s Natural Selections.”

Landscape architects can help by asking for certified stock and requiring planting specifications to include source-identified trees that are adapted to local site conditions. This demand will help to create a better supply. If we can ever get to the happy circumstance where native trees for urban landscaping are grown from

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sources similar to our climate and identified as such, maybe our tree planting efforts will be more successful and more economical.

If the tree you specify and plant does not have the genetic potential to survive and thrive in the conditions of your planting site, no amount of tending, fertilizing, irrigation, or pest control will help it grow as vigorously as a tree sourced from appropriate genetic stock. A tree’s chances for success lie first in its genes.

Ask about seed source.

Here’s hoping that all the trees you plant this year will live for one hundred years or more!

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BARB BOYSEN IS COORDINATOR OF THE FOREST GENE CONSERVATION ASSOCIATION, A NON-PROFIT GROUP WORKING IN SOUTHERN ONTARIO TO PROMOTE THE CONSERVATION AND RESTORATION OF URBAN AND NATURAL FORESTS. FOR MORE INFORMATION, SEE WWW.FGCA.NET.

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Trees for Life Richard Ubbens, City Forester for Toronto, speaks with Nancy Chater, Associate Member, OALA, about trees and how landscape architects can contribute to the health of the urban forest

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Trees for Life

Nancy Chater (NC): What can landscape architects do to improve the lives of urban trees?

Richard Ubbens (RU): Soil science is something that not only landscape architects but the urban forestry community as a whole could improve upon. Landscape architects are better than most urban foresters at thinking spatially and envisioning what the landscape is going to become, but there is a lack of soil science.

The challenge is: how can we provide, in an urban built form, a better environment so that trees are healthy and live as long as they should?

With the intensification of city building, there is good work going on in planning to make cities work better in a more dense form. But, still, the very first thing and last thing that is impacted is the soil. When the first truck backs up to remove the trees on a site, the soil starts to be compacted and disturbed. Then we have these practices of removing the soil, stockpiling it, building, and bringing soil back. When we are done, the soils are often unrecognizable.

When we say “let’s restore the soil,” very few people know what we are talking about. And without good soil we are not growing good trees.

NC: So the ways in which landscape architects specify soil and address methods of handling soil on a site have to be reviewed and become better informed by soil science?

RU: Yes. And there is no “one solution fits all” answer. For example, in Toronto we started addressing street trees at one point and the need to improve their growing conditions. We talked about soil volume, quality, structure, and drainage patterns. The next thing you know, our work on street trees was taken as the solution.

Yet we know that different species grow in different soils; we have slopes and valleys with differing drainage patterns, sun aspects, and so on.

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NC: Subsoils are very different.

RU: Exactly. We mess with soil chemistry, texture, and soil’s biological systems so that it becomes anaerobic, essentially a dead organism. Then we truck it back and call it “soil.” By that time it could be better called “dirt.” Soil is the biggest factor in why we are getting short-lived trees, unhealthy trees, and stunted trees in our cities.

NC: I’m familiar with compost tea at the scale of the garden. Is it being used at an urban scale?

RU: We have a couple of 1,000-gallon tanks at one of our yards, and our trucks will fill up with water and top up with compost tea and water our trees. It’s very effective.

TREE ROOTS AND INFRASTRUCTURE

NC: What do you think about industrialscale manufacturing of soils, including triple mix and compost?

RU: We also have to look at what is in the soil in terms of being full of utilities and infrastructure.

RU: Triple mix is too rich, too high in organic compounds, to be used for anything other than to get plants started. Two thirds of it will break down quickly; you will be left with only one third of your soil. At the City, we specify sand/silt/clay mixtures with a little bit of biomass to try to create something like a natural soil. More like a clay loam or sandy loam, because that’s what we have around here. Toronto has a lot of sand. That is very different soil, but it is natural. So we specify high sand content along our roads. It remains moist but it moves water easily; it moves nutrients easily. It doesn’t compact from vibration of traffic.

NC: The competition for space below grade in urban contexts.

We also have lots of clay soils naturally in our region. You would never spec a clay soil because you can’t put it back on a site without compacting the heck out of it. So you’ve got to go to a clay loam. I prefer to use parent soil material that is still alive, whenever possible. Ideally, we would put back the C, B, and A horizons. But that is a lot of work and expense, so we don’t do it.

The upper horizon needs to be a living horizon. That’s where compost comes in.

The compost being manufactured is alive, it’s full of microbes, but it doesn’t contain the natural soil microbes found in the forest. If there was more leaf mold, it would have more natural microbes. Compost is highly variable. You need to carefully specify what you are after with compost.

It’s a good product because it stimulates microbial action in otherwise dead soil.

Compost tea does that, too, and is highly valuable.

RU: That’s right. So understanding tree roots and their relationship to utilities is another emerging area. People ask: “if we have tree roots going in and around and through utilities, is that okay?” We know it’s okay as long as we design it well in terms of giving enough space so that eventually someone can access the utilities without compromising tree roots. Hopefully, gone are the days where we say, “We can’t plant trees here because we have a utility conflict.” I hope that landscape architects now understand where and how roots grow and why they don’t destroy utilities.

Roots are not aggressive, they are not out there damaging infrastructure. They are just opportunistic and going where soil conditions are good.

NC: Does that require a re-education of people on the utilities side as well?

RU: Absolutely. Landscape architects can help the engineers out there, especially on the utilities side, to understand how utilities can be located so trees are not going to be constantly affected, and similarly so the trees can be maintained and have enough soil volume without breaks in the soil

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Roncesvalles Avenue in Toronto has a modular system of raised planters with open bottoms, trench planting, and bridging sidewalk pieces in between planters that are structurally supported by concrete frames, allowing the soil volume to remain uncompacted.

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City of Toronto

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caused by all kinds of extensive excavation.

If we put the utilities deep enough, we can grow roots over them, no problem. We need to put utilities lower, and group them together. If we look at the science of tree roots, they need oxygen, water, nutrients— those are all at the surface.

We can look at San Diego as a precedent for change. They decided to place all utilities under the road, not in the planted boulevard. They recognized they were doing too much damage to trees when replacing or upgrading infrastructure. They recognized that trees have tremendous value; while roads are being replaced every twenty to thirty years, trees are lasting sixty to eighty or one hundred years.

We need to step back and ask: can we not relocate utilities to allow more growing space for trees? If we deal with trees and infrastructure on a project basis while keeping the big picture in mind, recognizing what twenty years of this kind of work will achieve, we can come up with much better standards.

early, and begin to prepare the soil for the next generation of trees. We want to do a lot better than that. For instance, on some of our planting projects we are now spending more than half of the budget on soil preparation. The costs are high but the results are that the roots will spread out from confined soil into surrounding areas that have been prepared properly.

We have examples now of tree planting methods for densely built areas that are more modular and allow for greater soil volume and uncompacted soil, using approaches such as bridging sidewalks, soil cells, and structural soil, combined with trench planting rather than individual tree pits.

PRIVATE PROPERTY AND THE HUNDRED-YEAR TREE RU: Beyond the engineered street, we know that there is far more private than public property in Toronto, and there are many more trees on private property. The work of landscape architects on private property, therefore, is especially important.

MISCONCEPTIONS NC: What are the major misconceptions about the way tree roots grow?

RU: A lot of people think of roots going down, but what we have to think about as going down is water—the movement of water up and down, and nutrients moving up and down. Tree roots grow out, mainly in the top 60 centimetres of soil with some roots going deeper, but 90 percent of the time the bulk of the biomass is in the upper 60 centimetres.

So while roots are important, we have to think as much about drainage and porosity in the soil. If we have a compacted subgrade and load in nice soil, with an abrupt transition, we don’t get normal moisture flow or proper drainage because we don’t have natural movement between the soil layers.

As a result, on dry days you don’t have water migrating up, as it would naturally, and you don’t have proper drainage. You may have a hardpan. The first generation of trees in this condition will grow roots and die

We know that the homeowner lives in one place for eight years on average and that tastes change over time, creating a tremendous impact on the urban canopy.

Look at the way we are using stone and pavers now in comparison to fifteen or twenty years ago when there was almost none and there was a lot more grass.

Outdoor entertainment space is in demand now and is being used more intensely, with bigger decks and patios.

In the face of these changes, we need to have people thinking about the hundredyear trees, not the twenty-year trees.

There needs to be something in every landscape plan for the hundred-year trees. If you look at older parts of Toronto, you find large trees around the property line. Around the perimeter, trees may last longer, so that may be a good place to locate new trees on private property.

Trees for Life

We are also promoting natural garden management in Toronto. For landscape architects working on ravine properties, it is important to use plant materials that create natural ecosystems and regeneration so the ravines are healthy. It’s a big opportunity because Toronto has 30,000 properties on our ravines.

GENETIC DIVERSITY RU: Genetic diversity is another key area.

We’re all used to dealing with clones.

What we should be dealing with is seedgrown material because we need the cross-pollination with different genetic stock, as happens in nature, instead of this massive cloning. There is tremendous natural variety among species that we need to embrace.

We also need to recognize that the urban environment is a dangerous place for trees in terms of their susceptibility to insects and diseases that can affect a whole species or even a whole genus, especially when the plant stock is genetically the same. There are various projects and small growers that are actively producing genetic diversity in plant material and making it available—a great resource for landscape architects.

RE-VALUING URBAN TREES NC: The approaches you have talked about—such as rethinking the relationship between utilities and tree roots, establishing new construction methods that support tree growth—require a re-valuing of trees on many levels. Do you see a paradigm shift? Are we at the beginning, or further in?

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RU: We are beyond the beginning. It’s not yet a wide-sweeping paradigm shift, but we are on the cusp of it. I think the younger generation—those coming out of university within the past five years, and those in school—understand that environmental challenges are huge. They have been taught the value of trees, the importance of water, the need to moderate climate. Whether they have a full understanding of trees is another question.

Trees are highly complex. Yes, we can all grow trees and shrubs, but can we grow them well?

On the economic side, we are starting to get projects with figures in the hundreds of thousands of dollars for trees to be removed and replanted. Sometimes developers are really surprised at the total value of the securities they have to put forward to municipalities. While the cost compared to the total project is still small in percentage, it is a lot of money. Another San Diego example involved a hydro line project that changed its course of action due to the cost of trees that would have to be removed and replaced. The project budget in total was about $20 million and the trees were just five percent of that, but that was still well over half a million dollars. As a result, they decided to put the lines under the road. That was the monetary value only. If they carried it one step further and went to the community and said, “We are planning to remove all these trees,” they would have witnessed a different value expressed, one that is more about the intrinsic value people put on trees. It’s something they can’t describe, they just know they like them and they are not prepared to see them go. People get very vocal. So yes, that piece about valuing trees is there.

NC: And then there’s what I would call the environmental infrastructure value—such as the canopy and all that it is doing in terms of cooling and air quality, moderating the urban heat island effect, and so on. That aspect is huge.

RU: Huge. For example, people always talk about the way trees can absorb carbon dioxide from cars. And they will, but what they absorb compared to the total output of all cars in a city is a depressingly small number. We’re doing a canopy study with the US Forest Services that will soon give us clear numbers. The studies are showing that trees can absorb virtually all of the nitrous oxide and sulfur dioxides that cars emit, and that’s substantial. And trees are offsetting fossil fuel consumption and providing carbon offsets because they are shading homes. If that number can be quantified, then you start talking multi-millions of dollars of value for the urban forest, depending on the size of the city. If we look at the value in terms of particulate matter that is taken out of the air by trees and the effect of that on health care, that is huge; if we look at trees in terms of skin cancer prevention, it’s huge.

We can look at real estate value and the question of what do trees mean to the importance of where I live. I always say that without the trees it’s a subdivision, and with the trees it’s a community.

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NANCY CHATER, ASSOCIATE MEMBER, OALA, IS THE TECHNICAL CORNER COLUMNIST FOR GROUND AND A MEMBER OF THE EDITORIAL BOARD.

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RICHARD UBBENS IS THE CITY FORESTER FOR TORONTO, RESPONSIBLE FOR THE OVERALL COORDINATION OF THE URBAN FORESTRY PROGRAM, INCLUDING FORESTRY POLICY, PLANNING, PROGRAMMING, PRACTICES, SYSTEMS DEVELOPMENT, FOREST MANAGEMENT IN RAVINES AND NATURAL AREAS, AND INTEGRATED FOREST HEALTH CARE.

Should it Stay or Should it Go?

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Should it Stay or Should it Go?

TEXT BY LORRAINE JOHNSON

Philip van Wassenaer’s glasses magnify the already intense look in his eyes, and when he talks, you get the feeling that nothing animates him more than an enthusiastic discussion about trees.

The founder and owner of Urban Forest Innovations Inc., based in Mississauga, van Wassenaer’s commitment to all things arboreal verges on obsession. (Get him going on the subject of heritage trees and pretty soon you’re experiencing the vicarious thrill of being high up—say, 300 feet—in the canopy of a 1,900-year-old Californian redwood giant...)

But what really gets him going is the subject of the urban forest— specifically, the need to protect old trees that others are inclined to write off.

“The average arborist has a propensity to panic about old trees,” he says bluntly of his profession. As do municipalities and homeowners. It’s understandable, of course, because with every major windstorm, there’s bad news: trees or branches down and the associated liability that goes with this.

The risky business of tree assessment

Until relatively recently, assessing tree hazards has been an inexact science—drilling, tapping, looking for signs of decay.

“But these methods don’t tell you how much decay there is and where,” says van Wassenaer. “There’s no quantification.” Thus, he’s championing something called the Elasto-Inclino Method (or, colloquially, the “pull test”), which was developed in Germany in the late 1980s and early 90s to scientifically test the safety and stability of trees. Wassenaer is the only arborist trained and equipped to conduct pull tests in North America and he has used this technique on approximately 150 trees in the past four years.

“It’s very similar to what structural engineers do when they apply structural engineering principles to safety analyses of buildings, bridges, and other structures,” he explains. Basically, the three key components of structural analysis include the properties of the material (in the case of trees, the compressive strength of green wood fibres), the force acting on the structure (for example, the wind), and the geometry of the load-bearing parts of the structure (the weight of the tree and the hollowness or soundness of the stem distribution of branches).

To conduct a pull test, one end of a steel cable is attached to a sling installed in the crown of a tree, and the other end is attached to a winch. The winch is used to simulate wind force acting on the tree’s crown; as force is gradually applied, a load cell measures the force in the cable. As the trunk bends, changes to the tree’s wood fibres are measured with an elastometer. Yet another device, an inclinometer, measures the reactions of the tree’s roots to the force. All of the data is analyzed by a computer program that extrapolates how a tree would react under gale-force winds and provides the safety margins for that particular tree.

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“These sophisticated tests allow us to make good decisions about the hazard level posed by a suspect tree,” says van Wassenaer.

It’s particularly useful, he notes, for trees that have had their roots severed during construction. “More than 50 percent of the time, we’ve tested trees slated for removal and been able to retain them. Sometimes, they require pruning, and the computer program allows us to show how pruning will increase the balance and safety of the tree.”

As for price, although it varies according to the specifics of the site and the tree, van Wassenaer suggests that anywhere between $1,200 and $2,000 is typical. Along with doing the test and running the data through the computer program, he provides a full report.

“We’ve had situations where the municipality says a tree has to be removed and the neighbours are in an uproar. On the other hand, we’ve had a homeowner say a tree is unsafe and the municipality wants to keep it. What we offer is unbiased and independent expertise to determine the safety of the tree.” While he is quick to stress that “as experts on risk assessment, we do not counsel people to keep dangerous trees,” it’s clear that for every tree saved by a pull test, van Wassenaer is thankful.

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LORRAINE JOHNSON, EDITOR OF GROUND, IS A BOARD MEMBER OF LEAF (LOCAL ENHANCEMENT AND APPRECIATION OF FORESTS).

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Tree stability testing

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Philip van Wassenaer Assessing decay at 95 m above the forest floor in the canopy of a giant sequoia, Eureka, California

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Philip van Wassenaer

Round Table

The Urban Forest As more and more municipalities implement tree protection bylaws, how is the urban forest faring and what can those who are involved with specifying and planting trees— arborists, landscape architects, and developers—do to ensure that the urban forest flourishes?

Moderated by VICTORIA LISTER CARLEY, OALA

BIOS/ VICTORIA LISTER CARLEY, OALA, A MEMBER OF THE GROUND EDITORIAL BOARD, HAS HAD HER OWN PRIVATE PRACTICE FOR MORE THAN TWENTY-FIVE YEARS. OVER THE LAST FEW YEARS, SHE HAS BEEN INCREASINGLY AWARE OF THE CHALLENGES AND CONFLICTS REGARDING TREES IN THE DESIGNED LANDSCAPE. PAUL MARSALA, OALA, IS THE FOUNDING PARTNER OF TERRAPLAN AND BRINGS MORE THAN THREE DECADES OF LANDSCAPE ARCHITECTURE EXPERTISE AND LEADERSHIP TO THE FIRM AND ITS CLIENTS. HE IS WELL KNOWN FOR HIS WORK ON NUMEROUS HIGH-PROFILE, LARGE-SCALE URBAN DESIGN PROJECTS. JANET McKAY IS THE FOUNDER AND EXECUTIVE DIRECTOR OF LEAF (LOCAL ENHANCEMENT AND APPRECIATION OF FORESTS), A NOTFOR-PROFIT ORGANIZATION THAT IS DEDICATED TO ACTIVELY INVOLVING TORONTO RESIDENTS IN URBAN FOREST STEWARDSHIP. IN 2003, McKAY RECEIVED THE ARBORICULTURE AWARD OF MERIT FROM THE INTERNATIONAL SOCIETY OF ARBORICULTURE FOR HER WORK IN COMMUNITY-BASED URBAN FORESTRY. SHE SERVED AS A MEMBER OF THE BOARD OF DIRECTORS OF THE ONTARIO URBAN FOREST COUNCIL FROM 2002 TO 2006.

VOJKA MILADINOVIC, B.SC.F., A GRADUATE FROM THE FACULTY OF FORESTRY IN SARAJEVO, IS AN URBAN FORESTRY PLANNER WITH THE CITY OF TORONTO URBAN FORESTRY DEPARTMENT. SHE IMPLEMENTS THE RAVINE AND NATURAL FEATURE PROTECTION BYLAW IN THE WEST PART OF TORONTO, REVIEWING TREE REMOVAL APPLICATIONS AND DEVELOPMENT APPLICATIONS. JEFFERY SILCOX-CHILDS, OALA, A SELF-CONFESSED "TREE GUY," IS THE MANAGER OF PARKS SERVICES FOR THE CITY OF VAUGHAN WHERE HE OVERSEES THE CONTRACT SERVICES, HORTICULTURE AND FORESTRY SECTIONS. NETAMI STUART, OALA, IS AN ISA CERTIFIED ARBORIST AND A LANDSCAPE ARCHITECT WHO WORKS FOR THE CITY OF TORONTO. PATRICIA THOMSON IS THE MANAGER AND HEAD CONSULTANT AT KELLY'S TREE CARE LTD. IN SCARBOROUGH. SHE IS AN ISA CERTIFIED ARBORIST AND HAS BEEN WORKING IN ARBORICULTURE FOR TWENTY-ONE YEARS.

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Victoria Lister Carley (VLC): All of our practices are affected by the regulations related to trees. Now that we’ve had a number of years living with these regulations (such as tree protection zones, permits for removal, etc.), how is it going? Is there meaningful improvement? Is there anything we should be doing to guide politicians to make better regulations?

care of by an arborist, the tree will suffer far less from whatever you’re going to build.

Knowing that you’re going to have to get a permit to damage the tree gives people an opportunity to think about the future a little bit. Start with an arborist or an arboriculture company, before you even get the permit, because with proper long-term care trees can be healthier.

Paul Marsala (PM): We’re working on a development where there were about ten trees, probably in the range of 12-inch calliper, which could not be preserved because of the grading situation. But the “three for one” legislation means we’re actually going to have more trees. The developer was in favour and had no problem in allowing more trees to be planted.

Typically, developers say “I don’t want trees on my property,” but that’s changing.

VLC: Going back to the issue of it being cheaper to just pay the fine relative to the time it takes to get a permit, do you think people would respond more positively if the system was faster?

VLC: I worry a bit about people getting rid of trees when they know trees are supposed to be protected. Are the fines enough?

Patricia Thomson (PT): Trees go missing all the time. Trees get removed without permits. I think the majority of people want to do things properly and they follow the rules, but others don’t, and trees are lost. Are the fines enough? No. For people with money who want to remove houses and rebuild, and the house that’s going to be rebuilt is worth $1 million, a $10,000 fine is hardly anything. Compared to changing the foundation, going through the time it would take to get a permit to remove the trees, to get an application in and have it denied, and the cost of re-doing plans, you get more benefit than the $10,000 cost.

Netami Stuart (NS): On the other hand, I have a client who wants to develop a house in downtown Toronto. He knows he’s going to have to do something about a tree that’s right beside his property. Fifty percent or more of the canopy is overhanging his property, but the stem is not on his property.

I was able to say, listen, you can prune your side of the canopy, and you can adjust the design of the house. So hire an arborist now, and do some pruning for structure, knowing that in five years, after being taken

PT: Certainly, that’s one of the complaints, that if they go for a permit to remove a tree, it may take up to three months. If you were to say we can get a decision in two weeks, they might go through the process but nothing says you’re going to get a permit at the end of the process. If the permit is denied, now you’re stuck with this tree that everybody knows about, they know the size, they know the condition, you’ve just admitted you have this tree, but you still need to get rid of it.

Jeffery Silcox-Childs (JS-C): It’s easier to plead ignorance than to ask for permission…

PT: That’s right. There are these underground “tree care” companies who come in on the weekends and they take trees down.

They make them disappear.

JS-C: I’ve actually had tree companies call me saying that they’ve been approached by people to take trees down. The people know there’s a bylaw but they don’t want to go through the process, so the tree has been removed by another company, and they’re sort of ratting on the other companies.

Janet McKay (JMK): A lot of people don’t know how to get proof, to gather the evidence that you actually need for the city to successfully charge somebody.

Vojka Miladinovic (VM): Also, a lot of people don’t want to confront their neighbours.

Usually, when people report infractions of

Round Table

that kind where a tree has disappeared, they won’t necessarily stand up in a court and say they have seen it. If a person is not willing to testify in court, there’s no evidence, basically. Even if a tree company goes and removes a tree, the property owner can still argue that he didn’t hire them. It’s very difficult to prove in court that the tree has been removed by the order of that person.

PM: So if the permit process is taking three months, what can be done to speed it up?

VM: We are definitely short-staffed; that’s a chronic condition. I know that on the private tree side, the city of Toronto has simplified the process of issuing permits to the point where a permit can sometimes be issued on site. So the city is trying to deal with it in a proactive way. But some permits are just not that simple. Sometimes you have to write a report to a councillor, involve the whole neighbourhood, and wait to hear if someone has an objection. And if someone has an objection, there has to be a process of consultation. The process has its course and unfortunately it’s designed in such a way that it kind of lasts. When it comes to ravine trees, unless the tree is really, really valuable, we tend to look for replacement rather than confrontation in most situations, or some kind of net environmental benefit for the site.

JMK: Sometimes the long wait has become a deterrent and so in that way, the lengthy process could actually work to save trees.

Some people might say, “There are existing large mature trees, maybe we’ll avoid that property because we know there’s a lengthy process and there will be costs.”

VLC: Do you think that, on the whole, there’s more public awareness, fewer trees being cut down, people being more cautious?

PT: Yes. From my experience, most people have heard about the tree-cutting bylaw. We get, as the years go by, fewer and fewer lectures over the phone about how unfair it is for the city of Toronto to tell them…

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JS-C: I get a few of those a week…

PT: Most architects are knowledgeable about the bylaw and when they start a project, they know that it takes x number of months or weeks to get this portion of the project done, and they know it takes at least three months to get through the tree-issue portion, and in the ravine, it can take a year to get through the whole process.

PM: Most large-scale developers know there’s a process and that it can sometimes take six months. Well, guess what? The rezoning is going to take a year anyway, so it makes no difference.

VLC: The bigger the project, the more people will expect that there are all these sections to go through.

NS: Vojka, if I submit a site plan, as a landscape architect, does the city’s forestry department have a department that checks the planting as well, to make sure that the tree is planted correctly and is watered and mulched? Is there somebody from the forestry department who checks that?

VM: The planners on the file go out and check. In the past couple of years we have included taking securities for the implementation of the plans that are submitted and approved. Before we return security, we want to make sure the planting has been done mostly according to the plan. So we do a review of the site conditions.

NS: My experience in Vaughan is that they’re tough—they actually send somebody who knows something about trees and tells you “No, you’re not getting your property assumed until somebody mulches those trees.”

down in their neighbourhood, and they don’t know what to do about it. They feel very helpless and it is a bit of an eye opener in terms of education of the public that the bylaw doesn’t stop the trees from coming down. It just puts a process in place that monitors how many are coming down, where and why, and what’s being replaced.

It’s not a perfect system. I think overall it’s been a positive thing, but it’s definitely not perfect. My expectation was that the city could withhold the building or demolition permit until tree protection was in place, but I learned it actually was not the case.

It’s only when they go to the committee of adjustment that they can really do that and this is a big gap.

JS-C: For small developments, where trees are involved they will not issue the building permit until the tree permit is in place.

VLC: It’s part of your building permit that you’re signed off on your tree permit.

NS: Yes, but the hoarding isn’t necessarily there…

VLC: But the inspectors do drive around and if your hoarding isn’t up, they definitely are on the case.

JMK: But even when you have citizens reporting problems, because of work loads and because of other factors, in my experience the response has not been as quick and people get very upset. We get a lot of phone calls from people who are desperate, really desperate, and they don’t know what to do or where to turn to save these trees.

CITIZEN INVOLVEMENT

NS: Is it usually about people with chainsaws cutting down trees or is it incursions into the tree protection zone, trampling, and driving stuff in?

JMK: LEAF is a community-based organization and we were really involved in getting the Toronto tree bylaw harmonized. We made a lot of deputations and a lot of community mobilization around getting support for that. We get a lot of phone calls from people who are upset that the tree bylaw is not saving trees, that trees are coming

JMK: It’s both of those. It’s also about neighbours being in the process of getting a permit where someone thinks they shouldn’t get a permit. Certainly, lack of tree protection zones is a problem that we hear about quite a bit. It’s the whole question of do you use the stick or the carrot? I don’t really think that we have any carrots. It would be great

Round Table

to have some carrots! Could we get incentives for developers and architects and other professionals to go that extra mile and really strive to design better buildings and structures and ways of doing things?

It’s not impossible to do.

PM: It’s called a tax break…

VLC: We’ve talked a bit about bylaws, but if you were to look at, say, getting permits in a new development, in what way could you encourage people to behave better?

Because one thing that’s always been said is that it’s expensive, it adds no value to the developer to follow the rules.

PM: We did a project in Kitchener, a commercial development, where we kept this grove of trees. It’s quite marvellous. As an incentive, Kitchener actually reduced the parkland dedication—it’s usually 5 percent and they cut it back to 3 percent.

vate tree-removal permit. They’re required to replant and they contact us because we have a backyard tree planting program.

But some people absolutely don’t want the replacement trees and they’re doing it simply because they have to. Those are really not the people we want to be serving in our program, because we’re looking for the best stewards for the trees that we plant. So this is something we’re struggling with.

JS-C: If they don’t want the tree and you know they don’t want the tree, whatever they put in is not going to survive, they’ll ensure it won’t survive. So I’d rather see the tree go somewhere else, within the community if possible, in an open space, wherever.

JMK: Toronto has a cash option. You can pay a fee rather than replant. That’s actually an interesting idea for a compromise.

JS-C: I’d like to see more of that happen.

VM: Trees increase the value of the property, especially big trees.

VLC: But now trees are also restricting people’s ability to develop a site.

VM: Yes, but the canopy and the whole ambience of the site increase the value. But it appears that the value of the tree dramatically drops when it interferes with your plans. I see so many situations where the neighbours are complaining and the developer is protecting the trees, but what the neighbours are really concerned about is the big house that’s going up. And they want to use the tree protection bylaw to restrict development on the property. So I think the mindset is different when you’re building and when you’re protecting trees, and it’s hard to marry those two. Another thing that happens—I would say 80 percent of the time—people will convince me that they just absolutely love their tree, but…

VM: We do prefer to see the tree replanted on site, if there is room, but if there is no room to plant on site, we accept cash in lieu. But once the tree’s planted, it becomes protected.

JMK: Is there monitoring of that?

VM: We do have one person who monitors plantings, but we would like to have more people doing that.

JMK: With LEAF’s program, we go back and do follow-up. I think that’s one of the reasons the city recommends us a lot. They know we’re going to plant native trees, the right tree in the right place. We send an arborist out to every site to decide on the species and the location. We do the planting and we do follow-up. So it’s a way for the city to know that the tree has actually been planted.

PT: You know the word’s coming: “but…”

THE ROLE OF ARBORISTS

VM: As soon as I hear “I love trees,” I know what’s coming...

NS: I think one thing that would really help in terms of getting trees planted and planted well on bigger sites, is to have general contractors understand what arborists do, and why they do it, and how they do it, and the

JMK: We now get quite a few referrals for plantings that are required as part of the pri-

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fact that arborists should be consulted more often. I think a lot of the time, tree protection measures and on-site pruning during construction and all those things that kill trees during construction, they happen because there aren’t tree care professionals doing the work, it’s just the guy with the bobcat, or the guy who knows how to make hoarding.

I think the industry could help to educate contractors about how to preserve trees or what constitutes good tree preservation on site. How do you get your general contractor to do that?

VLC: That would be the role of the professional, the landscape architect, architect, and planner. If you know that the developer is interested, you’d have an arborist as part of your team, and it’s how you structure the consultants’ contracts.

NS: It’s true, but if you have an engineering company or a design-build company in charge of the general contract, they call you a year and a half after they’ve finished planting the trees instead of having you there as they are planted: “Oh, can you do an inspection, we need our letter of credit,” that kind of thing. You really are pretty divorced from the planting of trees, and how your plans are executed and what it looks like, and what the conditions are like on site.

VLC: This leads to the next question, which is, how can new trees have a better chance of success? We’ve already referred to this: if somebody doesn’t want that tree to live, that tree isn’t going to live. We all know people can make things die remarkably well. How can we, though, increase trees’ chances?

PM: I think Vaughan is a good example. A subdivision may not be assumed until the forester signs off on it. If the whole development process takes three to four years, this forces the developer to maintain the trees.

Of course, he may not maintain them properly. Some do and some don’t.

JS-C: The way the market is right now, it seems like people want their letters of credit back so we’re getting a lot more developers going through for assumption.

Round Table

VLC: With the tighter economy the requirement is to get the money back faster. But then six months later they get their money back and nobody has responsibility for those trees.

JMK: I think community education and engagement is really key in terms of getting young trees to survive—workshops, training, and events—all kinds of community engagement that gets people to build their own skills, understanding, and knowledge of what it takes to help trees survive.

JS-C: Simple things like door hangers when planting: “Your tree requires x amount of water. Please help us out.”

JMK: Another issue is soil quality, in terms of having young trees survive. Often, soil quality is so poor that you’re limited as to what you can plant in basically clay subsoil that’s been compacted by machinery, with two inches of topsoil put back on, and then sod.

In some cases the drainage is really horrific, and then the lack of organic matter in the soil makes it really challenging to actually get trees established.

PM: One problem is that if you put all the topsoil in the boulevard, then there’s no structural support against the curb, so the developers are complaining that their curbs are falling apart.

JM: And each municipality makes their own standards in terms of details.

JS-C: And it’s constantly changing.

JMK: And there’s no provincial legislation or coordination for any of this. There’s no mention of trees outside of the natural environment in the Building Code or the Planning Act. LEAF is actually working on this issue now. We’re working with some other partners to look at what is the experience right now with the municipalities in terms of challenges, successes, and pit falls with tree protection bylaws. And we’re going to be doing a survey to get information from municipal forestry contacts across Ontario to

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start to build a case for the need for legislation at the provincial level and which Act it would best fall under and what that legislation change would look like.

VM: Education is very important. I tend to advise any developer that they should get an arborist on site before they design footprints, but obviously it’s not enough. The ISA and the OALA could also send the same message to the developers’ community and eventually it will take place. Nothing is going to be done if the developer is not ready to invest the required time. And I believe the same thing applies to planting conditions, whether it is in subdivisions or single-family dwellings. If a person is not willing to carry the cost of the required environmental benefit, then there’s not much we can do. And a lot of the time, the cost is actually the reason they don’t do it.

preserve and protect what we have, then how do we preserve and improve soil quality, then how do we plant new trees.

NS: I’ve heard Richard Ubbens tell a room full of landscape architects that they need to design subdivisions better so that trees will survive. And everybody was going, “Yeah, why don’t you tell the civil engineers that, because no one ever asks us how the curb is going to be designed, ever!” With wonderful exceptions of innovative developers, there are not many options for landscape architects to ply their trade in the subdivision design department.

JMK: The softscape always comes last, somehow. I think that’s a common complaint with arborists as well, that they’re consulted at the very end of the process instead of at the beginning when the design could actually be modified.

VLC: Well, one of the things I’ve observed is that as we’ve developed the bigger machines to dig the holes and so on, it’s quicker and easier to strip the whole site, put all the soil there, do the work, and put it back. This never used to be the case, so now the whole way in which people build the sites is based on really a lot of damage to the soil structure. Nobody is there on site to see that part of the process. You, Paul, would be more likely to do that sort of work.

Is it ever in your brief, to see how they strip the topsoil?

PM: The landscape architect or designer could recommend new, innovative approaches like porous paving or bioswales. That’s coming to the mainstream now; it is happening, but not fast enough.

PM: No. Very seldom.

JMK: Do you think that potential changes in provincial legislation could help that?

VM: There has to be something in it for the developer. There has to be a carrot.

JMK: There has to be a carrot and a stick: a stick for the minimum standard and a carrot for the higher standard.

VLC: And that’s the hard part—finding the carrot.

JMK: Eventually, ideally, as the public’s understanding of the value of trees and good soil increases, consumer demand will help drive change. But planting is not the whole answer to the question of how we protect and improve our urban forest. The first answer to that question is how do we

VLC: So the key seems to be: the earlier in the process that the tree is identified and professionals such as landscape architects and arborists are brought in, the better.

PM: We need to be involved right at the beginning.

NS: Yes, the more that legislation requires the work of a given profession or trade, the more that given profession or trade will be invited to do work by people who need that work to be done…

JMK: …and taken seriously.

MANY THANKS TO LISA MACDONALD, ASSOCIATE MEMBER, OALA, FOR TRANSCRIBING THIS ROUND TABLE DISCUSSION.

Sad Tree Challenge

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Sad Tree Challenge In Ground 03, we put out a challenge, inviting all tree enthusiasts to submit photos of the "saddest tree," including reasons for the nomination. And respond you did! We hesitate to characterize these trees as "winners." Instead, we offer this collage as evidence that trees need all the help they can get.

COORDINATED BY FUNG LEE, OALA

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Dundas and Ossington, Toronto

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Todd Irvine, LEAF Cobourg: "Its roots cannot breathe."

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Gina Brouwer "This tree with the split personality was planted where it had no room to grow."

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Gary Westlake Red maple, Vancouver: "It has endured so much in its short life."

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Catriona Hearn Norway maple, Toronto: "Though now an unloved species, does this tree deserve to be treated in this manner?"

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Real Eguchi Toronto: "Sad, but also hopeful because it refuses to die."

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Lorraine Johnson American elm, Highway 6, near the Niagara Escarpment: "A lone survivor of Dutch Elm Disease, now threatened by a highway widening project."

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Karen Moyer

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Sad Tree Challenge

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Bathurst and Bloor, Toronto: "Sad, because its 'house' is falling apart around it."

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Lorraine Johnson Winnipeg, Manitoba: "It has a very small area for root growth surrounded by paving; the branching area is full of power lines; it has a gaping trunk wound from a former vehicle impact; it has scale insects living on its twigs; and it is suffering from dehydration from de-icing salt spray from the street."

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Karen Asmundson "Tree as sign post."

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Jim Melvin Bloor Street, Toronto

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Ayako Kitta and Bryce Miranda Whitby: "If you look closely, it appears that there's a tear rolling over the damage from the tree tie."

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Lisa Shkut Downtown Welland: "Maybe not the saddest tree out there, but a common example of unfortunate urban tree planting practices."

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Sara Taylor Red maple, Vancouver: "While the restoration of the adjacent heritage building has been celebrated as visionary, this tree stands in silent testament to our apparent blindness to the urban forest."

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Catriona Hearn Nathan Phillips Square, Toronto: "A grand life cut short for human consumption in the guise of celebration."

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Marlise Eguchi Whitby

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Lisa Shkut

IF THE SAD TREE CHALLENGE HAS WHETTED YOUR APPETITE FOR VISUAL TREE LORE, VISIT THE GROUND SECTION OF THE OALA WEBSITE (WWW.OALA.CA) FOR LISA DOBBIN'S FEATURE ON "WEIRD TREES" FOUND IN ONTARIO.

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Letter From…

London

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The Would-Be Capital’s Canopy Putting the forest back in Ontario’s Forest City TEXT BY ALEXANDRA HOSSFELD, ASSOCIATE MEMBER, OALA

Growing up in London, Ontario, I was lucky enough to live by the edge of Warbler Woods, an environmentally sensitive area managed by the Upper Thames River Conservation Authority (UTRCA).

From my house, I could hike the nearby ski hill, and see the city stretching for kilometres through a sea of upland deciduous trees.

On lower ground, however, it’s apparent that the so-called Forest City isn’t living up to its epithet. The legacy of the Forest City, nicknamed after John Graves Simcoe attempted to create the capital of Upper Canada in the forest at the forks of the Thames River, has become somewhat ironic as the total forest cover has fallen to 10 percent. London lags far behind Ottawa at 30 percent, and Toronto at 20 percent. Even Kitchener-Waterloo, which conjures associations of innovation and technology as opposed to images of woodlands, surpasses London in forest cover.

Trees of the Forest City continue to be threatened by pests both large and small. “Pests” include the emerald ash borer, which has been discovered in trees at Springbank Park, and a much more formidable opponent: development. An article published by the London Free Press this past December describes how London developers have won the right to legally challenge the City’s protection of local woodlands, which was recently enhanced to make it easier to classify woodlands as ecologically sensitive. The ruling in favour of the developers puts forest areas the size of 1,000 football fields at risk, and further threatens tree cover in the city.

Although prospective development seriously jeopardizes London’s trees, several ongoing projects headed by various local organizations are focused on re-establishing forest cover in the Forest City.

One such group is ReForest London, which has partnered with the Urban League to launch their StraTreegic Plan, an initiative that aims to “address current and long-term needs for a healthy

London that will benefit by systematic and concerted tree planting.” The Urban League and the various partners that collaborated to develop the StraTreegic Plan, including the City of London, devised a four-part hierarchy of ecological restoration, which uses tree planting as a foundation for improving ecological linkages and biodiversity within the city. The hierarchy is based on activities that engage the community in planting trees first at the private level, expanding to street trees at a neighbourhood scale, treeing city parks and public property at a community scale, and finally linking the larger bioregion by reforesting natural watercourses and wetlands.

The StraTreegic plan is a vision that builds on the previous efforts of several organizations. It has identified hotspots that are most in need of attention, has an action plan for reconnecting those hotspots to the greater urban forest network and beyond, and has allocated volunteers to overcome limited financial resources.

The City of London’s forestry programs division is involved in an ongoing effort to infill established neighbourhoods throughout London with trees where space permits. Concurrently, the City initiated two projects targeting the urban forest this past summer.

One involved the UTRCA in spearheading a study that used the Urban Forest Effects Model (UFORE), a software modeling program developed by the United States Department of Agriculture Forestry Service. UFORE provides a standardized method of calculating structure, environmental effects, and value of the urban forest. In London, participant landowners were asked for access to their properties, and field crews collected data on resident trees that represented a sample of the total tree cover in London. This data will help stakeholders target the areas in need of improvement when it comes to protecting local woodlands.

Letter From…

London

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The Tree Watering Kit Project, also initiated this past summer by the City in partnership with ReForest London, was aimed at increasing awareness of the environmental roles city trees play, and the responsibility of citizens in keeping them healthy. Fivehundred watering kits were distributed to Londoners who recently received new trees in the boulevards in front of their homes. The kits consist of information regarding the project, as well as a recycled 20-litre bucket, to be placed at the base of the tree to allow water to slowly seep out of holes drilled in the bottom. The buckets hold enough water to supplement the tree roots for one week during periods without rainfall.

Although the results of the UFORE study and the Tree Watering Kit Project are yet to be published, the projects themselves are evidence that local stakeholders are aware of the irony of the Forest City, and are setting goals to restore its legacy. Not only do the projects benefit the urban forest and restore linkages to regional natural systems, they provide opportunities for social programming, benefiting the community. For instance, the Tree Watering Kit Project was assisted by youth from lower income neighbourhoods within London, providing job opportunities and experience.

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Volunteers planting trees at the Elsie Perrin Williams Estate, a project that is part of the "10,000 Trees for the Medway," which aims to naturalize the corridor along the Medway Creek in London

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ReForest London

Despite the meagre forest cover in London, there is still hope for the “De-Forest City,” as my dad likes to joke. When I climb the hills west of town and look out over the city, I think that if Simcoe could see what I see today, he still would have chosen this scenic landscape for the capital of Upper Canada.

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ALEXANDRA HOSSFELD, ASSOCIATE MEMBER, OALA, IS A RECENT GRADUATE OF THE BLA PROGRAM AT THE UNIVERSITY OF GUELPH, AND IS CURRENTLY LIVING IN THE FOREST CITY.

Plant Corner

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Branching Out Some unusual trees that deserve to be planted more often

TEXT BY LORRAINE JOHNSON

Surveying a typical street scene or peering into the back yards of most homes, one would be forgiven for thinking that there are very few tree species that actually grow in Ontario. Many factors have led to the relatively limited tree palette that tends to dominate our communities. Nurseries favour species that are well known, in demand, and economical to produce; municipalities promote proven survivors hardy in harsh urban conditions; and many landscape architects, designers, and contractors look for species that are readily available. The result, not surprisingly, is a relative lack of species diversity—Freeman’s maple, linden, and honey locust immediately come to mind.

However, if you’re looking for more unusual tree species for southern Ontario, the following are some relatively forgotten (or, at least, underused) gems to consider.

Paw Paw (Asimina triloba): Native to the Carolinian zone of southwestern Ontario, paw paw is guaranteed to spark interest and conversation. This tree produces the largest edible native fruit in Canada: it looks like a mango and tastes like a cross between banana and pineapple. The leaves are likewise tropical looking— large and luxurious. Small maroon flowers cover the branches in spring, before the leaves appear. Very easy to grow, paw paw does well in shade and sun, and reaches approximately 7 to 10 metres. It does not tolerate windy sites. To ensure fruit set, plant at least three trees for cross pollination. A wildlife benefit of this tree is that paw paw leaves are the preferred food for the larvae of the rare zebra swallowtail butterfly.

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Cucumber magnolia

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Andrew Leyerle Tulip tree

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Andrew Leyerle Paw paw

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Andrew Leyerle

Kentucky Coffee Tree (Gymnocladus dioicus): Increasingly used as an ornamental (indeed, the city of Toronto now makes it available for free front-yard planting), Kentucky coffee tree has many unique and attractive features. Its doubly compound leaves are the largest of any native tree. Its bark is distinctively scaly and its twigs knobbly. Although the flowers are not showy, the fruit—large brown pods that hang on the tree throughout the winter—are attractive. Kentucky coffee tree requires sunny conditions, does well in a wide range of soils, from sand to clay, and is especially useful in difficult conditions.

Plant Corner

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Plant Corner

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Tulip tree (Liriodendron tulipifera): A signature species of Carolinian forests, tulip tree can take your breath away in spring, when the tree is covered in large yellow flowers, and again in autumn, when the leaves turn a glowing yellow. The tree’s “tulip” name is doubly appropriate: the yellow flowers with orange bases resemble tulips, as do the four-lobed leaves in profile. Fast growing and reaching 30 metres, young trees require sunlight, but as they get older tulip trees are shade tolerant.

Redbud (Cercis canadensis): This relatively small tree (up to approximately 7 to 10 metres tall) is highly ornamental in spring— small, showy pink flowers cover the branches before the leaves appear. It behaves somewhat like a shrub, often with multiple trunks and a low canopy, though it can be pruned to more of a tree form. Leaves are heart-shaped, and the fruit is a purplish, flat pod. Redbud is adaptable to a broad range of conditions, from sun to shade, dry to moist soils, sand to clay.

Shagbark hickory (Carya ovata): Shagbark hickory is a tree that teaches patience. Its deep taproot means that large specimens are often difficult to transplant, so it’s best to start small; yet it grows very slowly. Think of it as a planting for the future, and imagine the joy someone else will have collecting (and eating) the sweet-tasting hickory nuts years ahead. Growing to approximately 25 metres, and long lived, this hickory’s most distinctive feature is the shaggy bark of mature trees. Best grown in sun to part sun, it is adaptable to dry or moist conditions, sand to clay.

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Plant Corner

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Hoptree (Ptelea trifoliata): The natural habitat of hoptree provides clues to its very tough, resilient character: it grows in the windswept, changing conditions of the Lake Erie shoreline, buffeted by wind, anchored in sand. Reaching 8 to 10 metres, it grows quickly, with crooked, gangly twigs. Flowers cover the tree in early summer with white clusters; the fruit is equally attractive, with papery disks that hang in clusters. The leaves are comprised of three leaflets and provide food for the larvae of the rare giant swallowtail butterfly. Hoptree grows best in sunny, open conditions, and is adaptable to sand or clay.

American Plum (Prunus americana): As showy as any ornamental plum, this native tree is covered in white to pink, fragrant blossoms in spring, providing nectar for insects. The fruit, which ripen in summer, are edible, if somewhat more sour than their cultivated relatives. A small tree, growing to approximately 3 metres, American plum prefers sun and well-drained conditions.

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Black Gum (Nyssa sylvatica): Although this tree is not well known in Ontario, many people prize a product that is sourced from it—or, rather, from bees nectaring at its blossoms: tupelo honey. Black gum requires sandy, acidic soil, and sun. It grows slowly, to approximately 15 metres. The flowers are not showy, but its small, blue-black fruit is attractive to birds and mammals. Striking features include the tree’s deeply fissured bark, which is often compared to alligator skin, and the spectacular fall colour—anywhere from yellow and orange to scarlet and purple.

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Cucumber magnolia

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Andrew Leyerle Redbud

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Mathis Natvik American plum

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Mathis Natvik

Chinquapin Oak (Quercus muehlenbergii): Unlike most oaks, which are slow growing, chinquapin oak is a fast-growing tree. It reaches 10 to 20 metres, and is very tolerant of urban conditions, making it a good street tree. Its leaves, also unlike other oaks, are unlobed and resemble the true chestnut (Castanea). It grows best in sun, and tolerates drought and sandy or clay soil.

Cucumber Magnolia (Magnolia acuminata): The only magnolia native to Canada, cucumber magnolia is a stately, tall-growing (to 30 metres) tree. Its yellow flowers appear in spring, followed by fruits that turn red in early autumn. Growing in sun or shade, it prefers slightly acidic to neutral soil.

A caveat: many of these species take work to track down. To find nursery sources, consult the Society for Ecological Restoration’s 2007/2008 Native Plant Resource Guide (see www.serontario.org).

A very useful source of information on the trees listed above is the book Trees of the Carolinian Forest: A Guide to Species, Their Ecology and Uses, by tree expert Gerry Waldron.

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LORRAINE JOHNSON'S MOST RECENT BOOK IS A COLLECTION OF ESSAYS, THE NATURAL TREASURES OF CAROLINIAN CANADA.

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TEXT BY NANCY CHATER, ASSOCIATE MEMBER, OALA

Urban Tree Planting

A quiet revolution has begun below the surface of the city. The competing conditions required for tree root growth, on the one hand, and standard construction of infrastructure, on the other hand, are being reconfigured into a more cooperative below-grade environment. We can look forward to long-term health of the urban canopy as a result.

The increasing use of relatively simple but transformative technologies such as structural soil, soil cells, and bridging sidewalks are facilitating the redesigned relationship between trees and infrastructure. The key is that these materials carry the structural loading of the city’s paved armature— roads, sidewalks, plazas, parking— removing the need for typical compacted base materials and allowing for uncompacted soil in the critical 60 centimetres below grade where 90 percent of tree root biomass is located.

Rethinking the relationship between utilities and tree roots is the other big area of change within this revolution in design below the ground. Clustering the pipes and cables of utilities together, placing them well below the primary root growth horizon, and even rethinking the placement of utilities altogether, are innovations that recognize the long-range planning required for sustained urban canopy health.

Structural Soil The term “structural soil” is used for soil mixes that are engineered to provide structural support for paving while maintaining porosity. The term was coined by the inventors of CU-Structural Soil at Cornell University’s Urban Horticulture Institute led by Dr. Nina Bassuk in the early 1990s. Patented in 1998, CU-Structural Soil has been used in more than 500 applications in Canada and the US. Comprised of 80 percent crushed stone (with no fines) and 20 percent soil (clay loam to maximize water and nutrient holding capacity) with a small amount of hydrogel to prevent separating, CU-Structural Soil forms a rigid lattice of angular stone that carries the load, with open voids between the stones to allow the soil to remain uncompacted.

Tree roots can grow freely while the movement of water up and down is unimpeded. As a result of the drainage patterns, moderate to highly drought-tolerant trees should be used. CU-Structural Soil is meant to be used under paving and can be installed adjacent to regular soil in open tree root areas. It can provide effective bridging between soft landscape areas so that tree roots can grow laterally below paving in a continuous course, helping to achieve the larger soil volume upon which tree health and longevity depend.

Clearly, the advantage of combining loadbearing support with useable soil is tremendous. As a recent technology, CUStructural Soil is still being tested for longterm results. Questions remain as to the effect of the organic matter becoming depleted over time and whether the voids between the crushed stones remain open.

The pH of the crushed stone, generally limestone or granite, has an impact on soil pH, and tree choices have to be made accordingly. The cost is approximately three times that of topsoil. Perhaps the

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Technical Corner

main limitation of CU-Structural Soil is that only 20 percent of the mix is soil. This is significant in light of the City of Toronto’s goals to achieve 30 cubic metres of soil per tree.

Soil Cells

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For Silva Cell information, see http://www.deeproot.com/.

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A modular matrix of stackable cells provides structural support without compacting the soil.

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Deep Root Partners, LP

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There is rapidly growing interest in the soil cell system by Deep Root, designed in collaboration with landscape architect James Urban, called the Silva Cell. This modular matrix of stackable cells (made of fibreglass and polypropylene compound with a galvanized steel-reinforced top deck) provides the necessary structural support for paving while the cells are filled with uncompacted soil. Significantly, more than 90 percent of the system is viable growing medium, and the soil type is flexible. The design accommodates space for oxygen between the finished grade of soil inside the cell and the top deck of the cells. The Silva Cell system also functions as a bioretention system for stormwater.

Across Ontario, about twenty-five projects are actively considering the Silva Cell system, while three major projects in Toronto, which are using soil cells, are underway including the Bloor Street Revitalization and Waterfront Toronto’s East Bayfront and Central Waterfront public realm initiatives (streetscapes and promenades) as well as the West Don Lands. James Roche, OALA, Senior Project Manager with Waterfront Toronto, notes that maximizing soil volume, providing structural support for paving, and the ability to organize utilities are the advantages of soil cells. Arborist and OALA Associate Member Joe McLeod of the Planning Partnership, who is working on the West Don Lands streetscapes, notes that the Silva Cell module cannot be cut and in some instances the particular size (60 cm x 120 cm x 45 cm) and geometry make it advantageous to combine soil cells with structural soil, with the structural soil acting as a bridge to accommodate turns and the interface with some utilities.

This innovative technology comes with an upfront cost, as a Silva Cell costs about $300-$500 per cubic metre (installed). The labour portion of the cost is expected to come down as contractors become more familiar with the process. CU-Structural Soil costs about $150-$200 (installed). If one compares actual soil volume, Silva Cell is less expensive (since only 20 percent of the structural soil profile is soil).

Clearly, the investment has to be weighed against long-term operational costs and tree survival rates, which are tied to the enormous economic and environmental values of the urban canopy.

Bridging Sidewalks The bridging sidewalk is a construction method employed in conjunction with trench planting for urban street trees.

Roncesvalles Avenue and University Avenue are examples of this in the City of Toronto, where raised street tree planters with open bottoms are located parallel to the road. Between the planters is a bridging sidewalk comprised of two curbs running parallel to the street, which support a slab overtop for pedestrian circulation. The planting trench runs beneath the entire length of the planters and bridging sidewalks, providing continuous soil volume for roots to spread laterally. Air space is left between the slab and the soil below for vital oxygen exchange. Vented pipes for air flow are integrated into the bridging sidewalk. City Forester Richard Ubbens notes that this planting detail could be combined with soil cells underneath a portion of the regular sidewalk closer to the building wall, with an oxygen connection linking the trench to the field of soil cells.

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NANCY CHATER, ASSOCIATE MEMBER, OALA, IS A DESIGNER AND PROJECT MANAGER WITH MARK HARTLEY LANDSCAPE ARCHITECTS IN TORONTO, AND THE TECHNICAL CORNER COLUMNIST FOR GROUND.

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Notes: A Miscellany of News and Events

competition The City of Toronto has declared Torontobased gh3 the winner of the June Callwood Park Design Competition, as recommended by the competition jury.

Deriving form from the sound waves of Ms. Callwood’s voice, the design of this 0.4-hectare park proposes a “Super Real Forest” as a strategy for enhancing Toronto’s tree canopy and contributing to the functioning and structural aspect of the city’s urban core. To learn more about June Callwood Park and the design competition, visit http://www.toronto.ca/parks/ June_Callwood_Park/index.htm.

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art For thirty years, London, Ontario-based artist Ron Benner has been making garden installations, using plants, seeds, signs, and photographs to critique the political, social, cultural, economic, and environmental consequences of colonialism. And, not incidentally, to create gardens that are as lushly beautiful as they are full of verdant provocation. A recent publication, Gardens of a Colonial Present, documents Benner’s numerous garden projects. Published by Museum London, the book includes essays by critics and curators and a wide-ranging rumination by Benner on the issues that propel his art, and the ideas, people, and travels that have influenced him. To order the book, contact ABC Art Books Canada at abc@abcartbookscanada.com.

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The voice wave form—taken from June Callwood's last interview— creates a number of glades or clearings in the June Callwood Park’s design scheme.

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gh3 A recent book documents artist Ron Benner’s garden projects.

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John Tamblyn An exhibition at the Design Exchange in Toronto explores design and urban agriculture.

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Design Exchange The Ft. Wright, Kentucky, Sanitation District No. 1 won a 2007 GRHC Award of Excellence for their green roof. Training courses for design and installation professionals are advancing the green roof industry.

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Green Roofs for Healthy Cities

The University of Guelph’s Office of Open Learning offers more than two dozen 12week courses in horticulture, landscaping, and turf management. These courses, facilitated by academic or industry professionals, help professionals advance their careers while studying from the comfort of their work or home. All that is required to participate is a computer with Internet access. For more information, visit www.horticulturecertificates.com or call 519-767-5000.

The Ontario Ministry of Natural Resources and Evergreen have launched a grant program designed to support the planting of 100,000 native trees on publicly accessible lands in cities and towns across the province. The core values of this program are community engagement and ongoing stewardship: all projects must be open to members of the public and be situated on publicly accessible lands. This program will provide funds to public agencies, institutional landowners, and community organizations undertaking volunteer-driven tree planting projects in 2009. Grants awarded will range from $5,000 to $15,000. There is no deadline to apply; applications will be accepted and processed on an ongoing basis. For information, visit www.evergreen.ca.

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greening

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exhibition A new exhibition at the Design Exchange in Toronto explores the role of design professionals in relation to the food systems of cities, and the impact that agricultural issues have on the design of urban spaces and cities. “Carrot City: Designing for Urban Agriculture” uses case studies such as the Green Arts Barns project in Wychwood Park (Toronto) and the Edible Campus project at McGill University (Montreal) to illustrate innovative food production approaches in urban contexts, and to address the question: what is the place of food in the city? For more information on the exhibit, which is on display until April 30, 2009, visit www.dx.org.

Green Roofs for Healthy Cities (GRHC), the trade association for the green roof industry in North America, is pleased to announce the launch of the accredited Green Roof Professional (GRP) program.

The first accreditation test is scheduled for the GRHC Annual Conference and Trade Show being held in Atlanta, Georgia, from June 3-5, 2009. The test will be based on the content of the four core green roof training courses offered by GRHC and available on an ongoing basis across North America. For a full training schedule, visit www.greenroofs.org.

green roofs Toronto is hosting the North American debut of the World Green Roof Infrastructure Congress from October 19-22, 2009.

Focused on green roofs and wall infrastructure design as a global solution to climate change, the congress will bring landscape architects, architects, construction professionals, and researchers from around the world to discuss innovative policies and programs that support the creation of green urban spaces. For more information on the event, to be held at the Allstream Centre, Exhibition Place, Toronto, visit www.citiesalive.org.

In 2008, London, Ontario—the Forest City—got a little greener with a bequest from the estate of Beryl Ivey to ReForest London. The environmental organization received $250,000 to establish an endowment and continue its tree planting programs in London. The majority of this gift will be used to establish the Beryl Ivey Community and Corporate Stewardship Endowment. Through the endowment, ReForest London will continue to empower community groups along with the corporate sector to improve their community and environment through volunteering, planting trees, caring for trees, and funding a healthy urban forest for generations to come. For more information, visit www.reforestlondon.ca.

health Economic arguments about the value of trees can be persuasive catalysts for tree planting efforts. Quantifying the social benefits of trees is also important, and social science research is providing the data.

Some of the most often cited research has been generated by Dr. Frances Kuo and associates at the University of Illinois at Urbana-Champaign. Kuo’s HumanEnvironment Research Laboratory (HERL), founded in 1993, and the more recent Landscape and Human Health Laboratory (LHHL) focus on the relationship between human health and greenspace. In a Chicago study, Kuo found that trees help poor inner-city residents cope better with the demands of living in poverty, feel more hopeful about the future, and manage their problems more effectively. For information about Kuo’s research, visit www.herl.uiuc.edu.

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pests

innovation

conference

Scientists with the Canadian Forest Service have started a trial campaign against the emerald ash borer in London, Ontario, using a new organic pesticide. The chemical, which has yielded positive results in applications in the United States and southwestern Ontario, is derived from the neem tree. It has no known negative effects on other animals or plants. The discovery of several afflicted trees in London has been a blow to the ongoing struggle to prevent the further spread of this pest.

The approach recommended by the Canadian Forest Service to deal with the ash borer’s arrival in London is to treat as many of the city’s “high-value” trees as possible. For more information, visit www.inspection.gc.ca.

When Spacing magazine launched its thinkToronto urban design ideas competition, it asked people 35 years and younger to answer the question, "If the next generation of urban innovators were given carte blanche to redesign or tweak Toronto, what would our city look like?" More than 100 teams took up the challenge, and the winners—twelve finalists and eight honorable mentions—range from the strikingly simple to the elusively complex. To view the work of these passionate city builders, visit www.spacing.ca/thinktoronto, or order a hard copy of Spacing's fifth anniversary issue (Fall 08 - Winter 09).

The Canadian Society of Landscape Architects/Association des architectes paysagistes du Canada invites you to the Sheraton Centre in Toronto, Ontario, to celebrate the 75th anniversary of the founding of the profession of landscape architecture in Canada. Mark your calendar now for August 13-15, 2009.

library

If you’re looking for one handy reference book that covers everything to do with planting trees in the urban environment, look no further than the recently published Up By Roots: Healthy Soils and Trees in the Built Environment. Written by landscape architect James Urban and published by the International Society of Arboriculture, this 479-page, voluminously illustrated guide presents the best-available information on how to ensure that trees are provided with everything they need to reach their full potential. Based on the idea that “the success of a tree is fundamentally linked to the soil in which it grows,” the book begins with the science of trees and soils in Part 1, then moves into practical strategies of applying this science through ten priniciples (for example, “preserve and reuse existing soil resources” is Prinicple 3, “respect the base of a tree” is Principle 5).

Written for a design audience, the goal of Up By Roots is to provide “sufficient knowledge of soil science, urban soils, and tree biology to make daily decisions during the course of a project.” To order a copy of this indispensable resource, phone 1-888-4632316 or email info@isaontario.ca.

OALA Council has undertaken a library expansion program to assist Associate Members and other exam candidates in their preparation for the LARE. The goal of the program is to have at least two copies of each reference book on CLARB’s LARE Recommended Reading List, allowing for one reference copy to remain in the OALA library at all times. (Some of these books are difficult to access and some are out of print.)

Please consider donating your reference books to the OALA library. Each book contribution will be acknowledged with a bookplate inserted inside the front cover, with thanks.

Visit the OALA website (www.oala.ca) to view an up-to-date list of required CLARBLARE reference books. To make arrangements for a book pick-up, contact Aina Budrevics, OALA Coordinator, at (416) 2314181 ext. 1 or by email, coordinator@oala.ca.

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The event promises to be a memorable one. The historical roots, the current state of the profession, and an exploration of our future will all be discussed through a series of workshops, sessions, panel discussions, and tours. Experts from across the country together with thought-provoking keynote speakers will challenge and stimulate our understanding of landscape architecture.

To register, contact Ms. Khadijah Jamal at (416) 595-1414 X 225 or khadijah@absolutevents.com.

infrastructure A new report from Ecojustice (formerly Sierra Legal) makes a compelling case for incorporating green infrastructure into urban design as a strategy to reduce combined sewer overflows. “Green Cities, Great Lakes” argues that one of the largest single sources of water pollution in the Great Lakes Basin is the combined sewer pipes that, during heavy rainfalls, release municipal sewage and stormwater directly into local water bodies. Using case studies from Ontario cities such as Windsor, Kingston, Toronto, and Hamilton, the report outlines some of the most effective methods of reducing stormwater flows: green roofs, downspout disconnection, rain barrels, permeable pavement, vegetated swales, rain gardens, and

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preservation/enhancement of urban forests. Of the latter, the report notes, “An increase in tree cover from 25 to 50 percent on a residential lot can reduce runoff from about 10 to 20 percent.” For a copy of “Green Cities, Great Lakes,” visit www.ecojustice.ca.

new members The Ontario Association of Landscape Architects is proud to recognize and welcome the following new full members to the Association: Vicki Armitage Heidi Baillargeon * Amy Bennewies * Jeff Bruin Christopher Canning Johanna Evers * Adriaan Geuze Francois Hebert * Glenn Herman Wing Wai Hui * Sarah Koeppe Julie Michaud Salisha Price * Anne-Claude Schellenberg Netami Stuart * Lisa VanderVliet * Xuan Wang Asterisk (*) denotes a Full Member not having custody and use of the Association seal.

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in memoriam JOANN LATREMOUILLE: A TESTIMONIAL

BY JOHN ZVONAR I met Joann Latremouille in 1989, when I was not long out of school. In spite of the generation gap, we hit it off, and our paths continued to cross over the next few years.

Joann secured a position at the Heritage Conservation Program (of Public Works) and, eventually, I also took a position there. In the realm of heritage conservation, Joann found her voice. She exhibited a mature poise and comfort level in working through the oftentimes challenging conservation process. Joann was tireless in her pursuits and unequivocal in her advocacy: she literally left no stone unturned.

Joann was a superb thinker and an even better writer—clear, precise. She employed all of her accumulated skills in the protection of cultural landscapes.

While there were many accomplishments, Joann’s most notable included: historic

landscape conservation guidelines for Parliament Hill; a cultural landscapes video for Parks Canada; and the execution of numerous studies, including Government House in Regina, the Cascades of Time Gardens in Banff, Neubergthal street village in Manitoba, and Buxton Settlement in southwest Ontario. The inclusion of a First Nations component was always a part of her clearly defined approach. In my mind, Joann’s legacy is undoubtedly her contribution to the recent Standards and Guidelines for the Conservation of Historic Places in Canada.

Closer to home, Joann had an unfettered enthusiasm for the heritage orchard she created on her rural property. Personally, I have lost a mentor, a muse, a steady hand at the wheel: someone who encouraged the rest of us to explore to our potential.

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Joann Latremouille

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John Zvonar

Interested in being involved with Ground: Landscape Architect Quarterly?

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The OALA Editorial Board is looking for volunteers who can help out with various tasks, such as research, transcription, and writing. Any level of commitment is appreciated, from researching upcoming events for the Notes section to transcribing Round Table discussions...

Fun, satisfying work—and the best part, no need to attend meetings!

To get involved, please e-mail magazine@oala.ca.

Artifact

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Writing with Wind Trees trace their signatures in the work of artist Tim Knowles 02

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Using drawing implements tied to tree branches, Tim Knowles’ images in the Tree Drawings series record on paper the effect of wind on trees. Each drawing becomes a kind of signature, revealing much about the different qualities and characteristics of the particular tree species: the light touch of a willow’s relaxed, flowing line, for example, or the stiff, scratchy, neurotic marks of a spiky hawthorn.

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Artist Tim Knowles’ Tree Drawings utilize trees in the production of drawings.

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Tim Knowles

The Tree Drawings are just one part of Knowles’ wider practice, which uses chance in the production of the work.

Generated by apparatuses, mechanisms, or systems beyond the artist’s control, much of the work seeks to reveal the hidden, or otherwise unnoticed motion of objects: the full moon’s reflection on undulating water, the motion of a parcel travelling through the postal system, or the intricate movement of one hundred weeping willow branches.

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TIM KNOWLES LIVES AND WORKS IN LONDON, ENGLAND. HE STUDIED AT BATH COLLEGE OF HIGHER EDUCATION AND HAS EXHIBITED WIDELY IN THE UK AND INTERNATIONALLY. HE WAS COMMISSIONED BY THE CONTEMPORARY ART SOCIETY AND THE ECONOMIST TO PRODUCE A NEW WORK FOR THE ECONOMIST PLAZA IN FEBRUARY 2008 AND IS CURRENTLY COLLABORATING WITH THE ROYAL MAIL ON AN AMBITIOUS SERIES OF NEW WORKS DUE FOR COMPLETION IN EARLY 2009.

FORTHCOMING SHOWS INCLUDE BITFORMS, NEW YORK, USA, AND PLYMOUTH ARTS CENTRE, UK. FOR MORE INFORMATION, VISIT WWW.TIMKNOWLES.CO.UK.