A National Deforestation Monitoring of Canada
A method for national deforestation monitoring of Canada is under development. The task described in this paper was to produce deforestation numbers for Canada’s 2006 National Greenhouse Gas Inventory Report to meet requirements for UNFCC and Kyoto Protocol reporting.
A combination of Landsat image interpretation, land activity records and expert knowledge was used. Relevant records collected included road construction, hydro reservoir flooding, hydro lines, and oil and gas pipelines. The main information source for deforestation was from satellite remote sensing interpretation. Change enhancements were used to identify potential deforestation sites (candidates). These were then examined along with the images themselves to determine if the site was forest at time 1 and that a permanent land use and cover change existed on time 2. A basis of this interpretation was national orthorectified Landsat coverages from circa 1975 (Landsat MSS), 1990 and 2000. Also acquired were 76 winter Landsat TM images circa 1990 and nearly 70,000 circa 1990 digitized and geolocated aerial photographs. Ancillary data supported the interpretation. This included GIS coverages of: road networks, hydrology, wetlands, wooded areas from provincial base maps, pits and quarry license areas, forest management zones and specialized oil and gas pipeline and well pad databases. The remote sensing mapping was generally done on sample cells 3-4 km square on a 10 or 20 km grid. The sample design varied for different deforestation strata.
The process resulted in national deforestation estimates that were input into a carbon budget model to also estimate carbon emissions and losses. The remote sensing component provided the bulk of the information and included a mapping of deforestation in samples covering 14.8 million ha for 1975-1990 and 36.8 million ha for 1990-2000. This paper outlines the remote sensing procedures used, the operational considerations and the lessons learned.