thumbnail

Tree species and size structure of old-growth Douglas-fir forests in central western Oregon, USA

Forest Ecology and Management

By:
and

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

We characterized the structure of 91 old-growth forests dominated by Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), using inventory data from recent (1985a??1991) old-growth timber sales in western Oregon. The data were complete counts (i.e., censuses) of all live trees >20 cm diameter at breast height (dbh, measured at 1.4 m above the ground) over a mean area of 17.1 ha at each site. Across all sites, Douglas-fir accounted for 79% of the total basal area (m2/ha) of all species. The average density of trees >100 cm dbh was 19 trees/ha and 90% of these trees were Douglas-fir. Species other than Douglas-fir constituted only about 20% of the total basal area at each old-growth site, on average, but largely accounted for the structural variation between sites. We used multivariate techniques such as cluster analysis, indicator species analysis, and ordination with non-metric multidimensional scaling (NMS) to identify and characterize six structural groups in terms of basal area in different speciesa??diameter classes. Almost 97% of the structural information was captured by the first (r2 = 0.841) and second (r2 = 0.128) NMS ordination axis. Geographic information systems (GIS) analysis and NMS indicated that the structural differences among groups of sites were associated with moisture, temperature, and elevation gradients within the study area. This type of analysis can be used to help define differences among old-growth forests and to set local structural goals for growing forests with old-growth characteristics.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Tree species and size structure of old-growth Douglas-fir forests in central western Oregon, USA
Series title:
Forest Ecology and Management
Volume
204
Issue:
2-3
Year Published:
2005
Language:
English
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
p. 329-343
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Forest Ecology and Management
First page:
329
Last page:
343
Number of Pages:
15