Defenders' Experts
Landscape-level Strategies
The most ambitious example of a landscape-scale plan for conserving forest biodiversity is the Northwest Forest Plan, designed for federal public lands managed by the Forest Service and the Bureau of Land Management in western Oregon and Washington and northwestern California. The plan established an extensive system of reserves to protect the northern spotted owl, listed as threatened under the federal Endangered Species Act, and other at-risk species.
The federal government's plan provoked intense controversy because it dramatically reduced timber harvest levels on federal lands in the Pacific Northwest while allowing continued logging in some of the region's remaining old growth forests. A decade later, the initial results in terms of biodiversity are just beginning to be understood. Analyses of 10-year status and trends under the Northwest Forest Plan show general improvements in most biodiversity-related measures, although spotted owl populations continued to decline in many areas.
However, scientists warn that in the long-term, landscape patterns in the northwest will become increasingly bifurcated, with very old forests, very young forests, and hardly anything in between. Under this scenario, the reserves on federal lands will be dominated by forests older than 200 years, and most of the rest of the landscape will be in intensively managed forests with maximum ages ranging from 35 to 80 years. Sharp, high-contrast edges between matrix and reserve lands may reduce habitat values in some old forests, and species that need old-forest habitats will be rare or absent on private lands.
Scientists working at the H.J. Andrews experimental forest in the western Cascade Mountains of Oregon have been examining an alternative approach under the Blue River Landscape Study in the McKenzie River watershed. The "dynamic landscape management" approach used in this study provides more flexibility in managing large blocks of land in ways that more closely mimic historic natural disturbance regimes. Computer modeling suggests that it may over time result in development of more older forests with better habitat values than those likely under the reserve and matrix system of the Northwest Forest Plan.
In this section. . .
Many conservation biologists are looking to the broader landscape for options to help conserve forest biodiversity.
Two landscape-level plans take different management approaches: the Northwest Forest Plan and the Blue River Landscape Study.
The Northwest Forest Plan is a system of late-successional reserves that are intended to provide essential habitat for northern spotted owls and other terrestrial wildlife associated with old-growth forests.
The Blue River Landscape Study is a long-term project designed to test an alternative landscape management strategy based on historical fire regimes and other disturbance processes.
Variable density thinning allows more flexibility to retain existing snags, logs and deciduous trees, as well promoting shrubs and complex canopies.
