关于日本扁柏人工林光能利用效率的研究(Ⅰ)——群落生产结构与现存量、生长量和光能利用效率

STUDIES ON THE SOLAR ENERGY UTILIZATION RATIO IN A CHAMAECYPARIS OBTUSA PLANTATION(Ⅰ)——COMMUNITY PRODUCTIVE STRUCTURE,STANDING CROP,INCREMENT AND SOLAR ENERGY UTILIZATION RATIO

本研究用相关生长法与分层割取法相结合测定的21年生日本扁柏人工林的现存量为160t/ha,生长量为16.5t/ha·a,净光能利用率为0.64%。在日本福岡地区这样的光能利用率不算高?莞鞑愕母晌镏手赜隓~2·H的相关生长关系计算了各部分的垂直分布。以太阳能多点测定计测算了林冠上部和林冠内各层太阳辐射量的季节变化。绘制了生产结构图。通过对林冠各部位叶的测定,证明了充分郁闭的日本扁柏林同日本柳杉林一样,可以区分为圆锥形、圆柱形树冠。其叶面积数和叶量密度分别为:35±5cm^2/g,495g/m^3;45±5cm^2/g,222g/m^3。以材积解析和群落生产结构、光能分布为依据论述了生产结构对光能利用的限制。

In this investigation we have determined that the standing crop of aChamaecyparis obtusa plantation of 21 years was 160 t/ha, the increment,16.5t/ha·a; and the net solar energy utilization ratio 0.64% by combiningthe correlative growth method with the stratified crop method. This ratiowas not high in the Fu Ku Ka district, Japan. From the relationship bet-ween the weight of dry matter and D^2·H correlative growth, the verticaldistributions of dry matter in different storeys were calculated. The sea-sonal changes of solar radiation energy in the top canopy and the differentstoreys inside were investigated with a sun-station system reader model700, which also gives the graph of the productive structure. From ourresults of investigation on the locations of the leaves in different partsin canopy, we suggested that the crowns with full closed canopy in a Cha-maecyparis obtusa plantation can be divided into cone and cylinder crownsas the crowns in a Cryptomeria japonica plantation. Their leaf area indicesand leaf densities were 35±5cm^2/g, 495g·/m^3; 45±5cm^2/g·and 222g/m^3respectively. The effects of the productive structure in a stand on solarenergy utilization were also discussed, according to volume analysis, com-munity productive structure as well as the distribution of solar energy.