Mapping older forests: satellites, statistics, and boots on the ground

The 1994 Northwest Forest Plan (NWFP) established a common management approach across federal land within the range of the northern spotted owl. It also established a monitoring framework to track, among other things, the plan’s effectiveness at maintaining and restoring late-successional and old-growth forests.

Station scientists Janet Ohmann and Warren Cohen contributed to the recently published 15-year report by the Interagency Regional Monitoring Team on the status and trends of these older forests the Pacific Northwest. Ohmann, Cohen, and their colleagues used a novel mapping approach that integrates satellite imagery, time-lapse technology that tracks forest disturbances on an annual basis, and field surveys to provide a wealth of data on stand structure and composition previously unavailable to land managers. The 15-year report also identifies disturbance trends across all forested lands in the region, which provides public and private land managers with a broader understanding of landscape patterns across multiple land ownerships. The amount of older forests on federal lands has remained fairly stable since implementation of the NWFP. Most loss that did occur stemmed from wildfire. On nonfederal land, timber harvests were the leading disturbance resulting in diminished areas of older forest.

The Pacific Northwest Region is using these data and mapping techniques to provide information to national forests planners as they revise their 10-year forest plans.

Citation

Ohmann, Janet; Meznarich, Paul. 2011. Mapping older forests: satellites, statistics, and boots on the ground. Science Findings 138. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.

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