The Distribution of Dihydroquercetin in Douglas-Fir and Western Larch

The distribution of dihydroquercetin, a 3-hydroxyflavanone, which is an anti-pulping agent and a durability factor, has been determined in the wood of six Douglas-fir and three western larch trees grown in British Columbia. A quantitative calorimetric method of analysis, applicable to small wood samples, was used. The concentration was determined at intervals radially from pith to cambium in cross-sections taken near the butt, middle, and top of each tree. In the heartwood, the content varied considerably within trees and between trees. The values ranged from zero to 1.5 percent in the Douglas-fir and from zero to 1.8 percent in the larch. Within trees, a general pattern of increasing concentration with increasing distance from the pith was evident in the heartwood of both species. Resinous wood, encountered in the fir, was found to have a lower concentration of dihydroquercetin than adjacent non-resinous wood. Appreciable concentrations were found in the sapwood of both species. The values therein ranged from zero to 0.56 percent.

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