为探明白桦树干导管特征的分布情况,由髓心向树皮逐年轮测定10株解析木树干不同高度的导管直径、管孔密度和导管组织比量。结果表明:随树干高度增加,导管直径减小,管孔密度和导管组织比量增加。由髓心向树皮,导管直径先迅速增加,在达到某一年龄后(伐根处20 a,胸径处15 a,枝下高处10 a)趋于平稳;管孔密度在伐根处基本以线性递减,在胸径处和枝下高处是先迅速减少,然后分别在15 a和10 a后趋于平稳;导管组织比量略有降低。这些结果表明白桦导管特征在树干内的分布具有空间差异。 In order to find out the distribution characteristics of the trunk of birch trunk, the diameter of the tube, the density of the tube hole and the ratio of the duct tissue of the 10 different tree trunks were analyzed from the bark to the bark. The results showed that as the trunk height increased, the diameter of the catheter decreased, the density of the tube and the ratio of the catheter tissue increased. From the medulla to the bark, the diameter of the catheter firstly increased rapidly, reaching a certain age (20 a at the root cutting site, 15 a at the breast diameter and 10 a at the top of the branch) tended to be stable; Decreasing linearly, at the DBH and branch height, firstly decreased rapidly and then stabilized at 15 and 10 years respectively. The ratio of catheter tissue decreased slightly. These results indicate that there are spatial differences in the distribution of white birch catheter features in the trunk.