A Comparison of Habitat Type and Elevation for Seed-Zone Classification of Douglas-fir in Western Oregon
Habitat type (identified by plant indicators) and elevation were compared as alternative bases for stratifying forest land into breeding zones or seed zones for reforestation. The comparison was based on the assumption that the genetic variation in an indigenous population of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) reflects the adaptively important environmental variation in the area inhabited by the population. Relative values for habitat type and elevation were then estimated by the amount of genetic variation explained by each in classification and regression models. Elevations, habitat types and tree genotypes were sampled in a 6100-hectare watershed in the Cascade Range of western Oregon. Parent trees (190) were from 114 locations (sources) in the watershed. Genetic variation was estimated by the performance (in 15 traits) of 3-year-old seedling families (190) grown in a common garden. Neither elevation nor habitat type were completely satisfactory for classifying environments into zones, in that elevation explained only about 56 percent of the source-related genetic variation, habitat type only about 35 percent. Forest Sci. 27:49-59.
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Document Type: Journal Article
Affiliations: Chief Plant Ecologist, Forestry Sciences Laboratory, Pacific Northwest Forest and Range Experiment Station, USDA Forest Service, Corvallis, Oregon 97331
Publication date: 01 March 1981