PARENT SESSION
Poster Session 37: Forest Ecology.
Thursday, August 5 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Patterns of canopy structural diversity in the managed forests of western Oregon.
Fiala, Anne1, Gray, Andrew2, Garman, Steven3, 1 The Evergreen State College, Olympia, WA2 USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR3 National Park Service, Moab, UT
ABSTRACT- Understanding trends in forest canopy structure can guide management for economic and ecological objectives in the Pacific Northwest. In this study, we evaluated patterns of vertical and horizontal canopy structure and understory cover along a successional gradient for three dominant forest types in western Oregon - wet-conifer, wet-hardwood, and dry-hardwood. Data were collected by the USDA Forest Service Forest Inventory and Analysis (FIA) program between 1995 and 1997. Line-intercept measures of canopy cover by species and vertical layer were recorded in five 0.09 ha sub-plots in each of 884 systematically located stands. Stands primarily ranged in age from 5 to 120 yrs with few stands >200 yrs old. Canopy cover and layering increased with stand age, although differences were evident among forest types. However, even after canopy closure, mean percent cover only reached about 85%. Shade-tolerant species comprised a much smaller proportion of cover across stand ages than was expected. Even the lower layer of cover remained low in shade-tolerant cover in older-aged stands. Surprisingly, cover levels and species diversity in the understory did not dramatically decrease during canopy closure. Our results provide forest ecologists and managers with information about the relationship between canopy structure and seral-stage that differs from traditional stand-dynamics models.
Key words: canopy cover, chronosequence, forest inventory, succession