As the rotation age of conifer stands in the Oregon coast range continues to drop, artificial recruitment of snags becomes increasingly important.
Multiple studies throughout Oregon and Washington have found that there is a negative association between stand age and number of snags (Ohmann et
al. 1994, Cline et al. 1980). Not only are these snags not abundant enough in young stands, but the ones that are present are often too small to host cavity nesting sites for most
species. This is because the natural snag recruitment in young Douglas-fir plantations consists mostly of suppression mortality during stem exclusion stage of stand development. This leads to stands that contain only small diameter snags which occur below the dominant canopy, and multiple studies have shown that small diameter snags do not provide effective habitat. Morrison et al. (1986) while investigating snag retention on Forest Service units, found that only 5% of the 398 nests were in trees less than 11.8 inches in DBH.
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