Even when the primary goal of a private or public forest is sustainable timber production, Hagar said, the lack of historic tree diversity, shrub and vegetation species may have long-term impacts on forest health, including ability to resist disease, soil function and fixation of nitrogen. An illustration of this concern is a current epidemic of Swiss Needle Cast, a tree disease occurring in areas that used to have many diverse tree and shrub species, but which have been largely converted to a monoculture of Douglas fir.
In the new synthesis, Hagar reviewed the life history accounts for forest-dwelling vertebrate wildlife species, and identified 78 vertebrate species in Oregon and Washington that are associated with non-coniferous vegetation, often the foundation of major food webs.
Among these species of concern are several three birds, one amphibian, and five mammals that already have special federal or state status. Declines of western bluebirds have been linked to reduction of available nest sites. Similarly, a major threat to the willow flycatcher is destruction of shrubby vegetation. Mountain quail populations have contracted due to loss of upland shrub habitats, plant species diversity and loss of woody vegetation in riparian zones. And a major threat to Columbian white-tailed deer has been removal of brush during logging or agricultural development.
Many species rely on a diversity of grass, herb, shrub and tree species for their energy needs, the report said. Fruits from deciduous trees and shrubs are a critical resource for migrant birds. Rodents cache seeds and nuts to get through the winter. Many species of insects depend on specific host plants, and in turn for
|Contact: Joan Hagar|
Oregon State University