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Providing evidence to improve practice

Individual study: Woodpecker habitat development in artificially created Douglas-fir Pseudotsuga menziesii snags, Oregon, USA

Published source details

Brandeis T.J., Newton M., Filip G.M. & Cole E.C. (2002) Cavity-nester habitat development in artificially made Douglas-fir snags. The Journal of Wildlife Management, 66, 625-633


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Use ring-barking (girdling), cutting or silvicides to produce snags Bird Conservation

A replicated study over four years in Oregon, USA (Brandeis et al. 2002), found no differences in the rate of use by woodpeckers of Douglas-fir Pseudotsuga menziesii snags created by different methods. Instead, only the length of time that a tree had been dead for affected foraging rates. Girdling (ring-barking), injecting with two different silvicides and cutting the tree just below the crown all had similar effects, killing most trees within two years (silvicide and cut trees died after a year or so, girdled trees died after two years but a higher proportion died overall). Chopping at the middle of the crown was the least effective in killing trees, taking over three years and killing fewer trees. Eighteen trees were treated with each method and some snags were inoculated with saprophytic (decaying) fungi.