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Further Study of Conifer Seed Survival in a Western Oregon Clearcut

Gashwiler, Jay S.
Ecology 1970 v.51 no.5 pp. 849-854
Peromyscus maniculatus, Pseudotsuga menziesii, Thuja plicata, Tsuga heterophylla, birds, clearcutting, conifers, germination, invertebrates, mice, mortality, seeds, shrews, Oregon
The survival of naturally disseminated, filled, seed of Douglas—fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), and western redcedar (Thuja plicata) was studied from 1960 to 1967. Ten per cent of the Douglas—fir seed survived from the start of seed fall until the end of germination the following year. Mice and shrews, mostly deer mice (Peromyscus maniculatus), destroyed an estimated 41% of the seed; birds and chipmunks (mostly birds) took 24% and other factors (nonviability of filled seeds, invertebrates, disease, and others) accounted for 25%. Western hemlock seed survival was 22%. Mice and shrews (mostly deer mice) destroyed an estimated 22% of the seed, birds and chipmunks (mostly birds) 3% and other agents 53%. The sample of western redcedar seed was too small to be reliable. Douglas—fir seeds were preferred by ground—feeding birds and small mammals–less than half as many hemlock were taken. Most Douglas—fir and hemlock seed mortality occurred before the start of germination.