Integration of LIDAR and Digital Aerial Imagery for Detailed Estimates of Lodgepole Pine (Pinus contorta) Volume Killed by Mountain Pine Beetle (Dendroctonus ponderosae)
The Canadian province of British Columbia is currently experiencing the most severe mountain pine beetle infestation on record. Estimating the volume of pine killed across the land base is critical for understanding the impacts of the infestation and for adjusting annual timber supply forecasts and allocating mitigation resources. At present, coarse strategic data sets are used to quantify pine volume losses associated with mountain pine beetle; however, we posit that high spatial resolution remotely sensed data sets may facilitate more refined estimates of volume losses. In this article, we proposed a method whereby LIDAR and digital aerial imagery are used in a sampling approach to estimate volume losses at the plot level. Fifty-five 0.25-ha photo-plots were established. Mean plot dominant stand heights were derived from LIDAR data. Tree species, mountain pine beetle attack status (red or gray), dbh, stem density, and mean plot age were estimated via manual interpretation of the aerial imagery. These attributes were then combined using species-specific equations to estimate the volume of pine killed within each of the sample photo-plots. The plot-level average volume killed by mountain pine beetle was estimated to be 40 m3 (SD = 27 m3), or 159 m3/ha (SD = 109 m3/ha), representing approximately 42% of total pine by volume. The plot-level procedures for producing estimates of infestation impact are developed to form the basis for a large-area, sample-based monitoring program.