From the point of view of ecological integrity and the responsibility of the park to protect and maintain a biotic community naturally associated with the ecoregion, we are primarily interested in the extent of two land cover classes, the old-growth forest, which should not decrease in the park, and the artificially cleared areas or the anthropogenic footprint, which should not increase. This program measures the extent of old-growth forest and tracks changes in the land cover class (measured in 30x30m grid cells) to the baseline year (1990). We use land cover datasets derived from remotely-sensed satellite imagery of the park to capture forest-stand replacement events, which in our case are due to construction-related clearing or natural stand-replacing events (e.g. windthrow from storms). The trend in the old-growth cover in Pacific Rim National Park Reserve is assessed by comparing the baseline extent of old-growth forest to annual loss in forest cover obtained from the annually updated Global Forest Change database. Disturbance has long been recognized as a primary underpinning of biological diversity in forested landscapes because it is a major determinant of spatial heterogeneity at multiple scales. Thus, loss of old-growth forest will result in a loss of bioregion-specific and endemic biodiversity.