BETWEEN-TREE AND WITHIN-TREE VARIATION IN THE ANATOMY AND SPECIFIC-GRAVITY OF WOOD IN OREGON WHITE OAK (QUERCUS-GARRYANA DOUGL)

In order to analyze the variation in wood properties within and betwee n trees of an underutilized tree species, we sampled six Oregon white oak (Quercus garryana Dougl.) trees from an 80-year old mixed stand of Q. garryana and Douglas-fir (Pseudotsuga menziesii [Mirb.] France) in the Coast Range of Western Oregon, USA. Fibre length, earlywood vesse l diameter, tissue proportions, and specific gravity were measured on samples across the diameter at two heights. Trees had a slight lean (2 -12 degrees), so we sampled separately both radii of a diametric strip that ran from the lower to upper side of lean. Variation between tree s, between the two heights, and between the lower and upper sides of l ean was not significant for most measured wood characteristics. The ex ceptions were vessel proportion, higher at the upper height, and speci fic gravity, higher at breast height (P < 0.05). There was significant variation (P < 0.05) between the youngest juvenile wood (growth rings 2, 4, and 7) and the oldest sampled mature wood (growth rings 32, 39, and 48) in fibre length (1.1 vs. 1.2 mm); earlywood vessel diameter ( 164 vs. 272 mu m), proportion of fibre (64 vs. 46%), vessel (12 vs. 27 %), and axial parenchyma (10 vs. 14%); and specific gravity (0.83 vs. 0.66). These characteristics showed demarcation ages between juvenile and mature wood of 10-26 years, depending on the characteristic. The r ay proportion (about 14%) showed no definite pattern of radial change. The results of this study may be used for estimating wood and fibre q uality of ring-porous hardwoods such as this species.