笋材两用毛竹林冠层结构及其生产力功能研究

Study on Crown Structure and Function of Phyllostachys pubescensStands for Culm and Shoot Production

研究了笋材两用毛竹丰产林的冠层结构特征与林地生产力功能间的关系 ,表明在一定立竹密度范围内 ( 2 2 50～ 3 150株· hm-2 )笋材两用毛竹林在人工经营措施的干扰下 ,竹冠冠幅受密度影响程度低 ,同胸径、枝下高、全高关系紧密 ,顺序为胸径 >全高 >枝下高 ;立地等级对竹林产量有显著影响 ,具体体现在对立竹度的显著影响 ,对冠幅影响不显著 ,笋材两用毛竹丰产林应选择半阳坡、半阴坡的缓坡林地 ( I类立地 ) ;毛竹林冠层具明显的垂直和水平二维分布规律 ,该分布规律有利于立竹充分利用地上营养空间。建立了竹林竹材产量同立竹结构因子间的数学模型 G=- 3 0 2 .2 7+42 .0 8M- 0 .0 0 0 56N+15.94 D+2 9.3 7h- 9.3 2 H,经微机模拟该模型计算值同实际产量间误差小 ,对生产中建立合理的竹林林分结构具参考价值 。

The relationship between crown structure and productivity of Phyllostachys pubescens stands for culm and shoot production was studied.The results showed that with certain stock density (2 250～3 150 culms per hectare),under the disturbance of artificial management,the crown width was less influenced by density,but correlated closly with DBH,clear bole height and total height (DBH>total height>clear bole height).Site quality had significant effect on the yield of bamboo stand,especially on stocking,but less affected the crown width. The crown layer of P.pubescens stand obeyed the vertical and horizontal distribution pattern,which benefited stocking bamboo to fully utilize the soil nutrient elements.A model for estimate the relationship between bamboo yield and stand structure factors was established:G=-302 27+42 08M-0 000 56N+15 94D+29 37h-9 32H.The crown width could be used as a factor to estimate stand productivity.