杨树树冠分维数与生长的相关关系

对用分维数表示的杨树冠层特征与生长量之间的关系进行研究。参试的28个杨树无性系4年生时的生长量存在显著的差异；用盒维数法表示的分维数(FD99)在无性系间也存在显著的差异，而用双表面积法估算的树冠分维数(FDa、FDv)在无性系问差异未达显著水平。相关分析表明：胸径与树高之间相关显著；而除用盒维数法表示的树冠分维数(FD99)与胸径生长相关达极显著水平外，其他情况树冠分维数与生长相关均未达显著性水平，表明并非叶面积越大生长量越大；树冠分维数与胸径生长相关明显大于与树高生长的相关。

The Relationship Between Growth and Fractal Dimension of Crown in Poplar

The correlation between growth and crown characteristics in terms of fractal dimension was explored based on the investigation of a 4-year-old poplar plantation which was established at Siyang Farm,Jiangsu province in 1997.A significant difference was found among clones both for growth traits and fractal dimension(FD (99)) which was estimated by the method of box-counting,but for the other two fractal dimensions(FD a,FD v) obtained by the two-surface method,no significant difference was found among clones although the difference was examined.The results also showed that there was a significant positive correlation between diameter at breast height and height,however,no significant correlation was found among fractal dimensions and growth except a significant correlation between FD (99) and diameter at breast height,which means a poplar tree with much more foliage may not have bigger growth.A trend was also explored that,compared with height growth,diameter growth had closer correlation with fractal dimensions of crown.