Dense, closed canopy, immature stands of coastal western hemlock (Tsuga heterophylla [Raf.] Sarg.), on northern Vancouver Island, responded well to thinning and, on some sites, to nitrogen fertilization. The best fertilizer net basal area response for the stand (5-18 m2 /ha; 7-28%) was found in thinned stands in the fresh and moist sites; the poorest response (up to 6 m2 /ha; 9%) was observed in the unthinned stands on moderately dry sites. The stand net basal area response to thinning was greatest when the treatment was applied at age 30 than at age 45. After 9 years, none of the thinned stands, either fertilized or unfertilized, had made up the basal area removed in thinnings. However, combining fertilization with thinning accumulated the extra growth produced by fertilization on fewer stems, thus producing a greater amount of valuable wood. Equations are provided for estimating net basal area response.
FRDA Research Report 137 (1229 KB)
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Updated July 24, 2015