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Landscape context for density management: implications of land ownership and ecological gradientsAuthor(s): Janet L. Ohmann
Source: In: Anderson, P.D.; Ronnenberg, K.L., eds. Density management in the 21st century: west side story. Gen. Tech. Rep. PNW-GTR-880. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station: 41-42.
Publication Series: General Technical Report (GTR)
Station: Pacific Northwest Research Station
PDF: Download Publication (110.52 KB)
DescriptionDensity management is implemented at a local (stand) scale, but is based on conservation goals that address a broader landscape. Although regional conservation eff orts such as the Northwest Forest Plan (NWFP) focus primarily on public lands, all land ownerships and allocations contribute unique benefi ts over the regional landscape that need to be considered as context for federal land management. In addition, whereas the NWFP emphasizes older forest and associated species, an ecosystem and multi-species management approach encompasses the full sequence of forest development. Recent results from NWFP Eff ectiveness Monitoring for late-successional and oldgrowth forest provide detailed maps of forest composition and structure over all ownerships, and for all stages of forest development, including trends over the NWFP period (1994 to present). More than two-thirds of older forest (overstory conifers >20 inches [50.8 cm]) was federally owned, whereas most early-seral forest was on nonfederal lands. However, early-seral stands have developed primarily following timber harvest and lacked the structural diversity typical of natural stands. Over the NWFP period, harvesting removed about 13 percent (491,000 acres [198,700 ha]) of older forest on nonfederal lands, whereas the loss of older forest from federal lands (about 200,000 acres [80,937 ha]) was attributed primarily to wildfi re. Overall, the monitoring data suggest there was a slight net loss of older forest on federal lands since the beginning of the NWFP, so losses of older forest to wildfi re apparently were roughly balanced by recruitment. However, recruitment was most likely through incremental stand growth over the 20-inch [50-cm] threshold, or from understory disturbances (including thinning) that eliminated smaller-diameter trees and increased average stand diameter, rather than from increases in stands of much larger and older trees. Land ownerships and allocations also were unevenly distributed across regional environmental gradients. Federal forests generally occupied higher elevations and lower-productivity sites, and a substantial portion of most of the mid- to high-elevation forest types were contained within reserves and managed for conservation objectives. In contrast, several forest types, such as oak woodlands, occurred predominantly at low elevations on nonfederal lands where they are managed for a variety of objectives, and are not well-represented in reserves. I will discuss potential implications of the monitoring results for stand-level management and for the conservation of older forests and associated species across the region.
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CitationOhmann, Janet L. 2013. Landscape context for density management: implications of land ownership and ecological gradients. In: Anderson, P.D.; Ronnenberg, K.L., eds. Density management in the 21st century: west side story. Gen. Tech. Rep. PNW-GTR-880. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station: 41-42.
KeywordsOld growth, late-successional forest, early-successional forest, forest monitoring, change detection, Pacifi c Northwest, Northwest Forest Plan, conservation planning.
- Mapping older forests: satellites, statistics, and boots on the ground
- Impacts of the northwest forest plan on forest composition and bird populations
- Northwest Forest Plan–the first 20 years (1994-2013): status and trends of late-successional and old-growth forests
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