Morikawa Yasushi, Hattori Shigeaki, Kiyono Yoshiyuki
Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin Kenkyu Danchi-nai, Ibaraki 305, Japan.
Tree Physiol. 1986 Dec;2(1_2_3):105-114. doi: 10.1093/treephys/2.1-2-3.105.
Daily transpiration before and after thinning was measured on six individual trees in a 31-year-old Chamaecyparis obtusa Endl. stand by the heat pulse method. After thinning, daily transpiration of a tree at a given level of solar radiation increased, and the difference between before and after thinning increased with solar radiation. The increase after thinning was related to a high rate of crown transpiration caused by greater canopy exposure and, subsequently, to the increase in foliage biomass per tree. Stand transpiration was calculated on the basis of two parameters, daily solar radiation and daily maximum vapor saturation deficit of the air. During the growing season (April to September), transpiration of a tree increased following thinning whereas transpiration of the stand decreased 21% after thinning. This decrease was associated with a 24% decrease in leaf mass of the stand following thinning.
采用热脉冲法，对一片树龄31年的钝叶扁柏林中的6株单株树木进行了间伐前后的日蒸腾量测定。间伐后，在给定太阳辐射水平下，树木的日蒸腾量增加，且间伐前后的差异随太阳辐射增加。间伐后的增加与树冠暴露增加导致的树冠蒸腾速率较高有关，随后与单株树叶生物量的增加有关。林分蒸腾量是根据两个参数计算的，即日太阳辐射和空气的日最大水汽饱和亏缺。在生长季节（4月至9月），间伐后单株树木的蒸腾量增加，而林分蒸腾量在间伐后下降了21%。这种下降与间伐后林分叶片质量下降24%有关。
