14 – September 2012, Australian Forests & Timber News
TECHNOLOGY
LiDAR technology is faster and more accurate By Rosemary Ann Ogilvie
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N 2008, the world’s tallest hardwood tree – the 101m Eucalyptus regnans dubbed the Centurion – was discovered by Forestry Tasmania (FT) not five kilometres from the Tarhune Airwalk in southern Tasmania. The discovery was actually made when a LiDAR (light detection and ranging) laser scanner flew over the area during an evaluation trial designed to identify its value in forestry operations. The trial outcomes revealed the remote sensing technology, initially developed for NASA during the 1970s, has the potential to provide a shopping list of benefits, including better-quality data; considerable cost savings; improved efficiency; reduced operational risks; and better protection of the environment. Consequently, FT made the decision to replace current photographic interpretation (PI) methods with LiDAR-based systems. The company called for tenders to phase in the use of LiDAR mapping systems across Tasmania’s State forests. Nearly one million hectares have been captured since the program started in 2009. “LiDAR is faster and more accurate than our current PI
system for mapping location and characteristics of forest stands,” says resources manager, David Mannes, who was involved in the project from day one and built the business case for adopting the technology. “It will enable the remapping of all FT estates in just three years, compared to the 20 it would take with PI.” Mannes explains that aerial photography essentially requires a person to interpret the images, where LiDAR is pretty much all automated. “So the amount of processing that goes into photography is exorbitant, and the required skills increasingly in short supply” LiDAR images provide a direct measurement of vertical forest structure. “We’ve been working to interrogate these LiDAR images so we can produce maps of other forest metrics,” Mannes continues. “We’ve found the LiDAR images can be used to estimate the vertical arrangement of the foliage making up the forest canopy, and also to estimate the number, height, and crown size of the individual trees. Tree height is one of the biggest determinants of timber volume, and a strong measure of the quality of the growing site, and so LiDAR’s accuracy and detail will vastly improve the quality of forest management.”
NZIF Foundation makes first awards THE NEWLY-established NZIF Foundation made its first awards at the New Zealand Institute of Forestry conference dinner in Christchurch. The foundation was established to encourage and support forestry-related education, training and research through the provision of grants, scholarships and prizes; promoting the acquisition, development and dissemination of forestry-related knowledge and information and other activities. Award recipients were: Chavasse travel award of $3,500 to Dr Stephanie Rotarangi to assist her to travel to Ireland to attend an International Union of Forest Research Organisations conference on biodiversity in Forest Ecosystems and Landscapes in Cork, Ireland. Dr Rotarangi has been invited to present a seminar at University College Cork and to enter a student competition for recent research. These will be based on her Otago University doctoral thesis on planted forests on ancestral land – the experiences and resilience of Maori Owners. Since completing her Ph.D., Dr Rotarangi, who has over 15 years’ experience in the forestry sector, has been appointed to the Māori Primary Sector Partnership team of the Ministry for Primary Industries, based in Dunedin. University undergraduate scholarship of $1,000 to Andree Callaghan, a third year Bachelor of Forestry Science student at the New Zealand School of Forestry at Canterbury University. Mary Sutherland scholarship of $1,000 to Larissa Anderson, a first year Diploma of Forest Management student at Waiariki Institute of Technology in Rotorua. Dr Andrew McEwen, Chair of the Foundation, said how pleased the Trustees were at the number and calibre of applicants. “This augurs well for the future of forestry in New Zealand, a sector which contributes significantly to New Zealand’s economy, environment and society and which requires highly trained individuals in order to make that contribution.”
Realising maximum economic value This information can also be used to estimate the age, the disturbance history and the optimal time for harvest of each spatial element in the forest, so the maximum economic value of the forest as a whole may be realised while its ecological values are maintained and enhanced over time. As LiDAR has the capacity to simultaneously map not just the underlying ground surface through the laser’s ability to penetrate forest canopy, it’s now possible to see terrain that was previously obscured. “It provides accurate measurements of the shape and slope of the ground, both of which are critical to forest operations such
as building roads and planning timber-harvesting systems,” says Mannes. “This information will help us to more accurately locate the numerous small streams, sinkholes and ancient landslips present in the forest estate much earlier in the planning process. In turn, this improves our estimates of the sustainable timber yield of our forests and reduces the risk of damage to forest soils and streams.” He adds that it will also improve the ecological sustainability of roading and harvesting practices, as these areas need to be quarantined from these operations. And it will considerably reduce operational risks: no nasty surprises such as losing bulldozers into creeks no one knew existed. Another benefit is LiDAR’s
ability to map exactly where trees are, whereas PI classifies forests into broad stands, providing little information about the variations within them. This in turn enables better planning decisions and will also mean up to 40% fewer ground sample plots are required to measure timber stocks and estimate future yields. “So the harvester gets a much better idea of what to expect on a coupe,” says Mannes. “It can even give us a good look at the quality of our plantations – and the entire plantation. We’ll be able to identify, for example, if there’s a small section that is perhaps not doing as well as the rest of the coupe, and apply fertiliser only to that patch.” LiDAR technology suitable continued on page 15.