http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Overstory/understory relationships in old growth Grand fir habitat types of northeast Oregon
Information regarding the dynamics of overstory/understory relationships in managed forests is required to support ecologically-based management of multi-resource production systems. The goal of this project was to define overstory/understory relationships existing on northeast Oregon industrial forests. Greater understanding of the impact of silvicultural practices on forest fauna is needed. Information is also needed on how to acquire data to develop ecologically-based multi-resource management plans. This project establishes quantitative relationships between overstory density and understory composition, production, and structure, and relates these to herbivore carrying capacity and productivity in managed forests. For this study, 76 stands in grand fir and mixed conifer forests were sampled randomly in two forested allotments. Plot clusters were established in each of the selected forest stands using a four-plot cluster design (Scott and Bechold 1995). Plots were evaluated for trees per hectare, tree height, tree live crown ratio, diameter at breast height, shrub density and cover, and herbaceous grass and forb yield and cover. The resulting data were analyzed statistically and a number of relationships appeared to exist between tree overstory and understory vegetation. Separating forest stands into forest ecotypes appeared to enhance the number of relationships as well as enhance the significance of overstory/understory relationships. Several attributes of tree overstory appeared to significantly influence understory vegetation and ground surface attributes of forest stands in northeastern Oregon industrial forests. In planning future timber harvest, consideration should be given to the spatial arrangement of tree overstory and the physical dimension of trees left in a stand. If predictive equations developed in this study are valid, shrub and herbaceous understories valuable as food habitat for a number of herbivore users can be developed. Consequently, any negative effect of timber harvest on these herbivores can be mitigated.
"Major subject: Rangeland Ecology and Management".
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references (leaves 61-63).