Cities can be densified nature-smartly

City planning is about balancing between different objectives of urban development. Urban densification has been considered a solution that both benefits the economy and curbs climate emissions from transport. However, densification should not lead to a decline in biodiversity nor in the well-being of residents. Studies show that diverse nature close to home has significant positive impacts on people’s well-being.

Steps to nature-smart densification

• In a sustainable city, biodiversity loss has been turned into recovery of natural environments, climate emissions into carbon sinks and the use of natural resources into circular economy, while urban nature supports the well-being of residents.

• Construction, the locations of shops and services, as well as increasing traffic can be steered through land policy and master planning so that natural environments and local green areas for urban residents are not reduced.

• The preservation of nature values and local green areas should be ensured in local detailed planning and in the implementation of construction projects. It is also important to utilise residents’ views of the recreational routes and green areas that are important to them.

• The aim of planning should be to avoid harmful effects on nature and to restore nature in construction instead of compensating for them elsewhere. Several benefits provided by urban nature, such as the absorption of meltwater and rainwater or the health benefits of local nature, cannot be compensated by nature areas elsewhere.

Urbanisation continues

The largest urban areas are growing, especially in areas with good public transport connections, in central cities and in some of the surrounding municipalities. More housing is needed in relation to the population, as individual dwellings are home to fewer inhabitants. Since the last decade, there has been less pressure to build on the fringes of urban areas and in suburban areas in surrounding municipalities.

According to the Residents’ Barometer 2022, the preferred comfort factors in residential areas are “natural environment” and “central location, short distance to services and short commutes”.1 Nature close to the home is important for the well-being and health of city residents and for biodiversity.

Wilder local nature supports well-being

Regular visits to local nature promote health by preventing, for example, inflammatory diseases, allergies and depression. An easily accessible natural environment can support the development of children’s immunity. The overall savings potential of Finnish nature’s health benefits is estimated at up to 2.5 billion euros, and a 10% reduction in local nature causes annual costs of 71-150 million euros alone by increasing the prevalence of depression. 2 Regular physical activity in local forests and parks helps people recover from everyday stress and improves their mood. Local nature with the best health and nature benefits include little-maintained environments, such as wild forests, which have fallen trees and thickets, as well as new meadows established in green areas.3

Cities have their own, valuable biodiversity. The nature values of urban nature may be richer than

those of a planted forest or drained peatland. Cities grow old deciduous trees, such as large oak trees, which provide a habitat for several hundred species and are rarely found in commercial forests. For example, the old manor and cultural environments in Helsinki are home to exceptionally diverse species of bracket fungi and butterflies.

Muscle-powered transport promotes health

Walking, running or cycling in a natural environment increases well-being. Walking is promoted by the density, mixing and good accessibility of urban functions. Dense, town-like construction is suitable for central locations where a wide range of functions can be placed within a short distance. The locations of services and surroundings of shops can encourage residents to visit them by foot or public transport. A green environment that encourages walking and cycling and supports a car-free lifestyle is especially beneficial for the older population, for those living alone and for low-income groups.4 The Finnish population is the fourth oldest in the world, and the number of people aged over 85 will double in two decades. Healthy lifestyle is a key means of guaranteeing the well-being of older people and improving their functional capacity. Green areas, pedestrian environments and sense of community are the most important quality factors in the living environment that increase the well-being of older people.5, 6

Urban nature is declining

In growth centres, urban vegetation and local green areas have decreased strongly in the 2000s.7 The amount of local green areas can decrease by single planning decisions, one plot or block at a time. Focus-

Planning detached house plots nature-smartly

The locations of buildings are defined in the local detailed plan

In construction plan, instructions are given on the locations of entrances, shelters, eaves and overhangs Plot and yard planning focuses on access routes and living area

Planning of detached house plots creates non-permeable surfaces

Soil-based, or permeable, surface area and vegetation can be increased

The impacts of choices made in the design of buildings and garden functions are multiplied and determine the amount of local green in the entire neighbouring area or block.

ing construction on already built areas maintains the amount of local green spaces and maintains the residents’ right to recreation in nature. The proximity to bodies of water and waterfront paths are especially important to many residents.

In a densifying city, the amount of urban greenery along streets, in yards, and on rooftops can be regulated. If the proportion of greenery is small, it can complicate stormwater management, create heat islands, and impair residents’ health. Extensive land-use projects can maintain old or, if necessary, implement new nature-based solutions enabling recreation. Permeable surfaces on yards and parking in car parks are often a better solution than extensive yard deck structures.

Nature helps control stormwaters and flood waters

Climate change will amplify heavy rains. In summer, heavy rainfall can increase by up to 30–70 per cent, which significantly increases the risk of flooding. Flood risks will continue to increase if the amount of non-permeable surfaces continues to increase as a city densifies.

The management of rain and meltwaters can be planned already in master planning. Natural stormwater management binds and purifies nutrients and solids ending up in water bodies. Many measures can be taken to prepare for heavy rainfall: stormwaters should primarily be absorbed and, secondarily, detained at their source. Flood route planning helps direct rainwater where it should go. Binding provisions can be issued on the percentage of the permeable surface area and water detention. It is wise to avoid building on areas susceptible to stormwater, or if you do, implement large-scale nature-based stormwater management solutions.8

Carbon is sequestered in soil and vegetation

Municipalities have several ways of influencing carbon sequestration in land use. Land use management offers the cheapest measures for balancing emissions before technological sinks are expected to be widely in use.

Carbon sinks can be preserved by avoiding construction on forested areas and by choosing appropriate management methods for municipally owned forests.9 In general, urban greenery and soil coverage promote carbon sequestration. In certain situations, ecological losses caused by construction can be compensated by biodiversity offsetting in accordance with the Nature Conservation Act. In addition, carbon removal through voluntary carbon markets can be utilised.

The amount of local green varies greatly between areas

Zoning can influence how much of the neighbourhood is covered by asphalt, stonework or buildings, and how much local green there is.

An area planned in the 2000s that is fairly extensively paved (Kivistö, Vantaa).

A fairly densely built area planned in the 1990s, with local green in gardens and green connections (Arabianranta, Helsinki).

Area planned in the 1940s with abundant local green and trees (Ruskeasuo, Helsinki).

Paved or bare ground

Building

Low vegetation (< 5 m)

High vegetation (≥ 5 m)

0 100 200 m

Source: Scalgo and Finnish Environment Institute, 2025. The images have been produced using the National Land Survey’s aerial photographs and terrain database, the Finnish Transport Infrastructure Agency’s Digiroad data, and the Finnish Forest Centre’s canopy model.

Carefully considered densification does not weaken well-being

Densification has been considered an important tool to promote climate change mitigation, the development of urban culture and the growth of cities. However, there are risks associated with densification: planning must be careful not to undermine biodiversity, human well-being, carbon sinks and stormwater management.

What is ecosystem accounting?

Ecosystem accounting is a tool that can be used to integrate natural capital in decision-making in a systematic manner. Ecosystem accounting is used to collect statistical data on the state of ecosystems, as well as on ecosystem services i.e. the amount and economic value of natural benefits to humans.10

Recommendations for urban densification

1 2 3 4 5 6 7

Different forms of land use can be directed to locations that are the smartest from the perspective of the existing urban structure and nature, across municipal boundaries if necessary. Local nature and the ecosystem services it provides should always be preserved in detailed planning solutions.

Complementary construction can be directed to areas already in use. Master plans should be used to prevent the reduction of nature areas caused by individual local detailed plans and construction projects.

Nature should be preserved in the planning and construction of plots and blocks. Unnecessary paving of public areas and yards should be avoided.

The surface area required by transport should be reduced and the accessibility of services without cars set as a goal for municipal land use planning and transport planning.

The vitality and carbon sequestration ability of soil and vegetation should be maintained. Biodiversity loss can be avoided by directing land use to areas already in use.

Management of rain and meltwaters can be planned for each catchment, i.e. water collecting area. Flood risks can be reduced, and the quality of stormwater and biodiversity improved, through nature-based solutions in the built environment.

The impacts of land use and construction on nature and the accessibility of local natural areas should be monitored in municipalities. If the state of nature deteriorates, land use regulations should be tightened.

References

1 Strandell, A., Nyberg, E. 2023. Asukasbarometri 2022. Kysely kaupunkimaisista asuinympäristöistä Suomen ympäristökeskuksen raportteja 29/2023. (In Finnish)

2 Tyrväinen, L., Halonen, J. I., Pasanen, T., Ojala, A., Täubel, M., Kivelä, S., Leskelä, R.-L., Pennanen, P., Manninen, J., Sinkkonen, A., Haahtela, T., Haveri, H., Grotenfelt-Enegren, M., Lankia, T., Neuvonen, M. 2024. Luontoympäristön terveysvaikutukset ja niiden taloudellinen merkitys. Luonnonvara- ja biotalouden tutkimus 76/2024. (In Finnish)

3 Korpilo, S., Nyberg, E., Vierikko, K., Ojala, A., Kaseva, J., Lehtimäki, J., Kopperoinen L., Cerwén, G., Hedblom, M., Castellazzi, E., Raymond, C.M. 2024. Landscape and soundscape quality promote stress recovery in nearby urban nature: A multisensory field experiment. Urban Forestry & Urban Greening 95, 128286.

4 Viinikka A., Tiitu, M., Heikinheimo, V., Halonen, J.I., Nyberg, E., Vierikko, K. 2023. Associations of neighborhood-level socioeconomic status, accessibility, and quality of green spaces in Finnish urban regions. Applied Geography, Volume 157, 102973, ISSN 0143-6228.

5 Padeiro, M., de São José, J., Amado, C., Sousa, L., Roma Oliveira, C., Esteves, A., McGarrigle, J. 2022. Neighborhood Attributes and Well-Being Among Older Adults in Urban Areas: A Mixed-Methods Systematic Review. Research on Aging, 44(5-6), 351-368.

6 Tiitu, M., Nyberg, E., Halonen, J. I., Pasanen, T. P., Viinikka, A., Lehtimäki, J., Vierikko, K. 2023. Comparing city practitioners’ and residents’ perceptions of a liveable neighbourhood in Finland European Planning Studies, 32(5).

7 Leppänen, P.-K., Kinnunen, A., Hautamäki, R., Järvi, L., Havu, M., Junnila, S., Tahvonen, O. 2024. Impact of changing urban typologies on residential vegetation and its climate-effects – A case study from Helsinki, Finland. Urban Forestry & Urban Greening 96, 128343.

8 Rytkönen, A.-M., Ahopelto, L., Helkimo, J., Olin, S., Keto, A., Leinonen, A., Häggblom, O. 2024. Valuma-aluesuunnittelun tiekartta vuoteen 2030. Valtioneuvoston julkaisuja 2024:6. (In Finnish)

9 Hildén, M., Niemistö, J., Ulvi, T., Pappila, M., Pihlainen, S., Seppälä, J., Lintunen, A., Minunno, F., Aro, L., Mäkipää, R., Hyppänen, T., Tuomala, M., Meretoja, M., Liedes, A., Peltonen, L. 2024. Opas maankäyttösektorin ilmastotoimien hyödyntämiseen kuntien ilmasto- ja luontotyössä. Suomen ympäristökeskuksen raportteja 33/2024. (In Finnish)

10 Kopperoinen, L., Barton, D.N., Costadone, L., Hurskainen, P., Kruse, M., Lai, T.-Y. 2022. Urban experimental ecosystem accounting pilot in the Nordic cities. TemaNord 2022:557.

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Authors: Riku Lumiaro, Jonne Hytönen, Maija Tiitu, Mikko Sane, Ville Helminen, Antti Rehunen, Anna Strandell, Kari Oinonen, Leena Kopperoinen, Kari-Matti Vuori, Hanna-Liisa Kangas, Marko Tainio.

Editor: Saara Sivonen

Layout and graphics: Satu Turtiainen Cover: Riku Lumiaro

Publisher: Finnish Environment Institute (Syke)

ISBN 978-952-11-5751-6 (pdf)

ISBN 978-952-11-5752-3 (print)

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