Variation of Wood Density in Larch in Northeast of China

Wood density was investigated in seven dahurian larch (Larix gmelinii Rupr.) trees grown in northeastern China. Six discs (about 5 cm thick) were cut from each tree (i.e. from the root stem, at breast height (1.3m), and at 20%, 40%, 60%, and 80% of the total height). For each disc, a thick sliver with parallel sides was cut out along the diameter of the disc. The sliver was about 40-mm thick, with the pith located in the middle. Eight small pieces were cut from the sliver with equal distance from pith to bark. Wood density of small piece was obtained using water displacement method. Significant variation in wood density was observed among sections for different heights. Wood density increases from pith to bark for all height categories and decreases from the stump to top of the tree height.