Performance of Four Planted Conifer Species Within Artificial Canopy Gaps in a Western Washington Douglas-Fir Forest
Regeneration performance of planted grand fir (Abies grandis [Dougl. ex D. Don] Lindl.), coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla [Raf.] Sarg.) seedlings was studied for 3 years within artificial canopy gaps in a mature Douglas-fir forest near Tacoma, WA. Third-year survival of Douglas-fir and western redcedar did not vary with gap size, but peak survival of grand fir and western hemlock occurred at gap sizes of 0.13 and 0.14 ha (0.32 and 0.35 ac), respectively. Peak values of stem diameter occurred within a narrow range of gap sizes for all species. Because of their larger initial size and superior performance across a range of gap sizes, Douglas-fir and western redcedar were concluded to be the most suitable species for group selection on droughty, glacial-origin soils of western Washington.
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Author(s): Timothy B. Harrington, Warren D. Devine
Publication: Tree Planters' Notes - Volume 61, Number 2 (2018)
Volume: 61
Number: 2