Science Service System

Summary of Proposal LAN0225

TitleGauging the Health of Canada’s Forests: Insect Defoliation Mapping and Monitoring in Support of Sustainable Development Planning and Reporting.
Investigator van der Sanden, Joost - Canada Centre for Mapping and Earth Observation, Natural Resources Canada
Team Members
Environmental Scient Landry, Robert - Canada Centre for Remote Sensing, Natural Resources Canada
Research Scientist Hall, Ron - Canadian Forest Service, Natural Resources Canada
Environmental Scient Thomas, Sylvia - Canada Centre for Remote Sensing, Natural Resources Canada
Environmental scient Deschamps, Alice - Canada Centre for Remote Sensing, Natural Resources Canada
SummaryInsect defoliators are important natural disturbance agents on Canada’s forests, affecting more than 10 million ha and accounting for the loss of 4 million m3 of wood per year from our sustainable timber supply. To derive these estimates, areas of disturbances are currently generated largely from aerial surveys. These surveys lack spatial detail and precision, and are largely confined to managed forest areas resulting in many areas of Canada without pest damage information. The goal of this project is to advance our knowledge about the state of Canada’s forests through application of the high frequency TerraSAR-X data and investigate its synergy with aerial survey and land cover information. This project will develop and demonstrate innovative approaches for using TerraSAR-X data to map and monitor the area, location and spatial distribution of insect defoliation. This information will support Canada’s sustainable development strategy and help Canada meet its international reporting obligations. Specific objectives for are i) to investigate the potential of TerraSAR-X data for the application studied as a function of polarization and angle of incidence. ii) to explore the synergy of TerraSAR-X data with optical satellite, aerial survey and land cover data, and (assuming positive results) iii) to demonstrate the techniques and products within the existing Natural Disturbances Framework supported by Natural Resources Canada and the Canadian Space Agency. Thanks to its higher frequency of operation, TerraSAR-X is expected to offer more potential for the application considered than currently orbiting SAR systems like RADARSAT-1 and Envisat ASAR. Our attempts to map and monitor insect defoliation with optical satellite systems are often obstructed by a persistent cloud clover. The time window for mapping insect defoliation, of aspen in particular, is limited to about 4 weeks per year. In this respect, the short revisit time (11 days) of TerraSAR-X is a distinct advantage. We propose to determine the optimum polarization configuration and incidence angle range on the basis of images acquired in the stripmap mode. Thanks to its larger swath width, the ScanSAR mode offers more potential for demonstration and, ultimately, operational application. For the 2007 and 2008 defoliation season we would request of the order of 20 dual polarization stripmap mode images of varying incidence angles and 10 ScanSAR mode images. The key deliverables will include: 1. progress reports as per request of DLR 2. descriptions of tools developed for application of TerraSAR-X data to insect defoliation mapping and monitoring 3. demonstration products illustrating the potential of TerraSAR-X 4. conference presentations and scientific publications. The majority of the funding for our research is expected to be provided by our employing agency, i.e. Natural Resources Canada. Also, we have recently submitted a project proposal to obtain funding for described and related activities from the Canadian Space Agency (Government Related Initiatives Program).
Detailed reportProject has been completed. Four stripmap VV/VH products acquired over northern Alberta, Canada in 2008 were applied in the study. Results have been presented during the 4th TerraSAR-X Science Team Meeting (14-16 Feb 2011) by Dr. F. Charbonneau. The title of his presentation was "TerraSAR-X activities at CCRS". The results confirm an increase in backscatter in the leaf-off condition relative to the leave-on condition. As expected, the best contrast between leaf-on and leaf-off was observed in the VH polarisation. But this contrast was limited to about 1 dB only (which was lower than expected and thought to be the result of cross-talk beteen the VV and VH channel). TerraSAR-X derived backscatter change products that show defoliation patterns were found to correspond reasonably well with patterns observed during aerial surveys and mapped using optical EO images.

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