An experiment for assessing vertebrate response to varying levels and patterns of green-tree retention

The emphasis of forest management in the Pacific Northwest has shifted rece ntly from the production of timber resources to the maintenance or restorat ion of biological diversity and ecosystem functioning. New standards and gu idelines for management emphasize the retention of forest structures (live trees, logs, and snags) to reduce logging impacts, to enrich reestablished stands with important structural features, and to enhance connectivity acro ss forest landscapes. However, little is known about the effects on wildlif e of varying the level and spatial distribution of retained structures in f orests of western Oregon and Washington. Replicated and controlled experime nts within the Demonstration of Ecosystem Management Options (DEMO) study a re beginning to quantify the effects of varying the level and spatial aggre gation of green-tree retention during forest harvest on a variety of ecosys tem components (e.g., vertebrates, invertebrates, vegetation, fungi), as we ll as snow hydrology and social perceptions of these types of regeneration harvests. Eight replicate blocks of six experimental treatments have been e stablished on the Umpqua National Forest in Oregon, and on the Gifford Pinc hot National Forest and Capitol State Forest in Washington. The objectives of the wildlife studies are to quantify patterns of species richness, evenn ess, and relative abundance of birds, small mammals, bats, and amphibians b efore and after harvest to examine short-term treatment responses. Pre-trea tment sampling has been completed on all sites, harvest treatments are in p rogress, and post-treatment sampling has begun. In this paper, we present a n overview of our hypotheses and methods, and document the occurrence and r elative abundance of species prior to harvest of the study blocks. Long-ter m studies of Vertebrate response, habitat associations, and trophic interac tions are planned. Results will inform managers on the consequences of alte rnative forest management strategies.