Conifer seed survival in a western Oregon clearcut

A study of the survival of naturally disseminated tree seed was made in a clear-cut area on the H. J. Andrews Experimental Forest in the Cascade Range of western Oregonduring 1955-60. From start of seed fall until the end of germination in late spring the fol-lowing year, 12% of the Douglas-fir (Psendotsuga menziesii) seed survived. Ground-feedingbirds and small mammals caused 63% of the seed loss and other agents 25%. Thirty-oneper cent of the seed of western hemlock (Tsuga heterophylla) lived from the start of seed falluntil the end of germination. Of the amount lost, birds and mammals took 16% and all otherfactors 53%. A large proportion (65%) of western redcedar (Thuja plicata) seed survivedduring the same period. The entire loss was attributed to causes such as nonviable filledseeds, disease, invertebrates, and others. Ground-feeding birds and small mammals showeda definite preference for Douglas-fir seeds. Only about 25% as many hemlock seeds weretaken, and redcedar was not consumed in appreciable amounts. Most of the seed depreciationsby birds and mammals occurred from start of seed fall to start of germination; other factorstook heaviest toll during the germination period.