Spore Deposition ofHeterobasidion annosumin Thinned Coastal Western Hemlock Stands in Oregon and Washington

Publisher Website
Google Scholar
Abstract
Deposition of spores of H. annosum was studied in both commercially and precommercially thinned stands of western hemlock (T. heterophylla) at 5 coastal locations in Washington [WA] and Oregon [OR]. Petri plates containing selective medium were exposed at approximately monthly intervals April 1981 to June 1982. Average spore deposition rates were higher in precommercially than commerically thinned stands, with the highest average rate (19,557/m2 per h) occurring at Seaside, OR. The maximum spore deposition rate was 44,353/m2 per h in a precommerically thinned stand at Tillamook, OR. Deposition rates in precommercially thinned stands were higher at the southern sites (Cathlamet [WA] Seaside and Tillamook) than the northern sites (Sekiu and Hoquiam [WA]). This trend did not occur in commerically thinned stands. Deposition rates were, in general, highest in autumn and spring and lowest in winter and summer.