Session Information
| Session | Poster Session | | Date | Monday (2008-04-07) | | Time | 5:00 PM - 7:00 PM | | Room | Grand Terrace |
Presentation Information
| Presenter | Peter Potapov | | Title | Tree cover loss estimations in the boreal forests using MODIS time-series data sets | | Affiliation | Geographic Information Science Center of Excellence, SDSU | | Authors | Peter Potapov, Matthew Hansen, Stephen Stehman, Thomas Loveland, Kyle Pittman | | Keywords | Boreal forests, MODIS, Monitoring, Tree canopy change | | Presentation Type | Poster | Abstract:
Estimation of tree canopy cover change is important for boreal forests, one of the most extensive forested biomes, due to its unique role in global timber stock, carbon sequestration and deposition, and high vulnerability to the effects of global climate change. While the use of satellite-based observations for monitoring disturbance regimes at regional scale has been established, internally consistent, timely monitoring of the entire boreal forests has not been implemented. We used time-series data from the MODerate Resolution Imaging Spectroradiometer (MODIS) to produce annual forest canopy loss hotspot maps. These maps were used to: 1) stratify the boreal biome into regions of high, medium and low likelihood of forest canopy loss and 2) analyze the results of sampled blocks of Landsat-scale forest cover loss data per stratum via a regression estimation procedure. The stratified random sample of 119 blocks was interpreted for forest cover and forest cover change using high spatial resolution Landsat imagery from 2000 and 2005. Area of forest cover loss from 2000 to 2005 within the boreal biome is estimated to be 1.69% (standard error 0.127%) of the total biome area, and represents a 3.95% reduction in year 2000 forest cover. Annual and regional variation is pronounced. The pan-boreal change area estimates reveal significant increases in forest cover loss due to wildfires in 2002 and 2003, with 2003 being the peak year of loss within the 5-year study period. The proportion of identified forest loss relative to regional forest area is higher in North America than in Eurasia. Of the MODIS forest cover loss hotspots, 57.9% are attributed to wildfires, 32.7% to other disturbances, including logging and insect outbreaks, and 9.3% to an uncertainty class to which no specific disturbance factor was assigned. Comparisons of the MODIS hotspot map with Canadian Forest Service data validate its use as a stratification tool. Overall, results illustrate the robustness of the forest cover loss algorithm that could be used as an operational and cost-effective method for producing timely and accurate estimates of biome-wide forest area change. |
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