不同经营方式下杨树人工林叶面积分布与动态研究

本文对集约经营与粗放经营杨树人工林分的叶面积垂直分布及其片节动态变化进行了对比研究，结果表明：集约经营林木叶面积的数值明显大于粗放经营林木的叶面积数值，林木个体间叶面积差异显著且与林木个体的胸径大小成正比。整个生长季节内，集约经营林木冠层叶面积数值较大，林分生长季节较长；而粗放经营林木叶面积相对较小，生长季较短。叶面积较大，生长季较长是导致集约经营林分生产力较高的主要原因之一，通过研究，建立了生长季不同时期内，集约经营与粗放经营林木累积叶面积指数垂直分布的拟合模型，可用于对叶面积的估算。该研究为进一步探讨杨树人工林冠层光分布、计算冠层光合产产量奠定了基础，为我国杨树人工林的速生、丰产提供了科学依据。

THE DISTRIBUTION AND SEASONAL CHANGE OF LEAF AREA IN POPLAR PLANTATIONS MANAGED IN DIFFERENT WAYS

The vertical distribution and seasonal change of leaf area were studied in intensive and extensive culture poplar plantations. The result showed that the cumulative leaf area index(CLAI)of intensive culture trees was obviously higher than that of extensive culture trees during the growing season. According to the sample trees, the weighted mean of leaf area index in two stands was 30362*!m2/m2 and 21786*!m2/m2 respectively. Seen from the seasonal dynamic of leaf area, the intensive ones showed relative longer growing season than extensive ones. The higher leaf area and longer growing season contributed to the higher productivity in the former. The vertical distribution of CLAI in two plantations can be accurately simulated by the relative models according to the observing data. Even in the uniform plantation where the difference of leaf area in different individuals obviously existed, the leaf area appeared positive relation with its diameter at breast height(DBH).