无瓣海桑人工林树冠生长特性分析

通过对雷州半岛无瓣海桑人工林树冠生长及林木分级进行分析，提出冠长、冠积等生长预测模型。结果表明：随着林分密度的增加，无瓣海桑各分级木的冠幅差距趋于减小；冠长率的变化总体上随着林分密度的增加而减小，但各分级木之间冠长率的差异趋于变大；不同密度无瓣海桑林分优势木、平均木和被压木的平均冠积分别达58．500、32．597、19．214m3，各分级木平均冠积的差异随密度增加而减小；无瓣海桑具有一级分枝高度较低的特点，60％以上的无瓣海桑其枝下高〈1m。

Analysis on Crown Growth Characteristics of Sonneratia apetala Plantation

Based on analyses of the crown growth and stem classification of Sonneratia apetala plantation on the Leizhou Peninsula, the growth prediction models for crown length and crown volume were built. The results showed that the difference in crown width among different stem classes was reduced as the stand density was increased. On the whole, the difference in crown length among the stem classes increased along with the increase in stand density, while the change in crown length ratio was reduced. The average crown volume of the dominant trees, mean trees and the overtopped trees in plantations with different densities was 58. 500 m3, 32. 597 m3 and 19. 214 m3 respec- tively, indicating that the difference in the average crown volume of different stem classes tended to decrease as the stand density increased. It was concluded that S. apetala the lowest branches over 60% of the S. apetala trees was was characterized with lower branches, the height below within 1 m.