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 Through the research on crown structure of intensive management and extensive management of poplar plantations, it is shown that the branch length distribution and canopy shape of intensively managed canopy are conducive to intercepting light. The leaf area index is measured by grading standard wood method and the intensive management is 3 0 36 2m2 m-2, extensive operation of 21786m2 m-2, the former is 14 times the latter. The cumulative leaf area index of intensive and extensive management can be estimated by the following models: ICLAI = 0.2607 Z1.80 3 0 e-0 .164 3Z (R2 = 0.991 9) and ECLAI = 0 .0 6 39 Z2 .64 80 e-0 .2 53 0 (R2 = 0.996 0). Taking the average wood length as the independent variable, the accumulated leaf area index of intensive and extensive management was calculated by the above model. The results were 3 1 2 2 1m2 m-2 and 2 2 6 1 9m2 m-2, respectively, which were different from the measured values 2 8% and 38%. The vertical distribution of cumulative leaf area of ​​standard and intensive management stands has a close positive correlation with the results of corresponding model simulation. The vertical cumulative leaf area index distribution of stand can be estimated reliably by using the measured values ​​of standard wood. Crown shape has a significant impact; conical crown, larger branches and higher leaf area index is an important factor in the intensive management of the higher productivity