【摘要】 通过对集约经营与粗放经营杨树人工林树冠结构的研究表明 :集约经营树冠的枝长分布和树冠形状有利于对光的截获 ;用分级标准木法实测叶面积指数 ,集约经营为 3 0 36 2m2 m-2 ,粗放经营为 2 1 786m2 m-2 ,前者是后者的 1 4倍。集约与粗放经营林分累积叶面积指数可以分别用下列模型进行估测 :ICLAI=0 .2 6 0 7 Z1.80 3 0 e-0 .164 3Z(R2 =0 .991 9)和ECLAI=0 .0 6 39 Z2 .64 80 e-0 .2 53 0 (R2 =0 .996 0 ) 。分别以平均木冠长为自变量 ,用上述模型计算集约与粗放经营林分累积叶面积指数 ,结果为 3 1 2 2 1m2 m-2 和 2 2 6 1 9m2 m-2 ,分别与实测值相差 2 8%和 3 8%。集约与粗放经营林分标准木的累积叶面积垂直分布与对应模型模拟的结果具有紧密的正相关 ,利用标准木的测定值能可靠地估测林分的垂直累积叶面积指数分布 ;栽培措施对树冠形状有显著的影响 ;圆锥形树冠、较大的枝倾角和较高叶面积指数是集约经营林分生产力较高的重要因素更多还原

【Abstract】 Crown structure (including vertical distribution of primary branches, crown form, vertical changes of branch inclinations, vertical distribution of leaf area and cumulative leaf area index) of intensively and extensively cultivated poplar plantations were studied here. The results showed that the layer with maximum branch length of trees in intensive management plantation was relatively lower than that of extensive ones. Most trees in intensive management plantation were with coniform crowns, but in extensive management plantation, crown form appeared parabolical cylinder crowns. The distribution pattern of primary branch of trees in intensive management benefit to light interception. Branch inclination angle was also varied significantly with crown length. The estimated LAI by destructive method was 3 0362 m\+2m\+\{-2\} for intensive management plantation, and 2 1786?m\+2m\+\{-2\} for extensive management plantation. The CLAI for intensive and extensive management plantations can be simulated by the folowing models: I CLAI =0 2607*Z\+\{1.8030\}e\+\{-0.1643Z\}(R\+2=0.9919) and E CLAI =0.0639*Z\+\{2.6480\}e\+\{-0.2530\}(R\+2=0.9960). If simulated by the crown length of standard trees in two plantations, the CLAI was 3 1221 m\+2m\+\{-2\} and 2 2619 m\+2m\+\{-2\} for intensive and extensive management plantations, which was only about 2\^8% and 3.8% difference compared with these by destructive method estimations respectively. There were high linear correlation relationship between the standard tree and simulated model for both plantations. The cultivation measures have significant effects on the crown structure. The conical\|shaped crown, large branch inclination and higher CLAI are contributed to the higher productivity for intensive management poplar plantation.更多还原