Effects of forest policy on landscape pattern of late-seral forest of the Western Olympic Peninsula, Washington

Forest harvest policies and regulations in the Pacific Northwest region of the United States have changed considerably across all land ownerships over the last 25 years, primarily in response to concerns over threatened and endangered species. For example, in July 2001, Washington State adopted new forest practice rules for private ownerships, which were aimed primarily at improving habitat for aquatic and riparian species. Before adopting the new rules, an environmental impact assessment was conducted in which three alternatives were considered in detail for their contributions to riparian habitat. Implications for upland species were not considered, although riparian protection has the potential to make contributions to habitat for obligate late-seral species. Effects of the three management alternatives were projected on private lands 200 years into the future, holding constant current practices on other lands managed for timber (federal, tribal, and state). The resulting distribution of late-seral forest across the Western Olympic Peninsula was compared. Simulations predicted that late-seral forest would cover between 39 and 48% of the landscape, well above the 8% that it currently occupies. Five to 21% of this late-seral forest would be on private lands (compared to <1% currently), and 71–85% on public lands (compared to 91% currently). Landscape pattern analysis indicated that the total amount of late-seral forest was significantly different among the three scenarios. However, there was no discernible difference in interior forest area, edge density, and mean distance between patches between a “no-action” alternative and the alternative that was ultimately adopted into rule. The most protective alternative had significantly more interior forest area and greater mean distance between patches, but it also had significantly higher edge density as a result of the linear nature of the riparian reserves and small patches of steep, unstable slopes. Our analysis framework will be useful for evaluating the effects of alternative management scenarios on landscape pattern across broad geographic areas with complex ownership.