Yokota T, Ogawa K, Hagihara A
Laboratory of Forest Ecology and Physiology, School of Agricultural Sciences, Nagoya University, Nagoya 464-01, Japan.
Tree Physiol. 1994 May;14(5):467-79. doi: 10.1093/treephys/14.5.467.
Nighttime respiration was measured at monthly intervals over one year on the aboveground parts of five sample trees in an 8-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand, by an enclosed standing-tree method. The respiration rate rose rapidly from early spring to a maximum in June, and decreased abruptly in July and then gradually toward autumn and winter. The seasonal change in the respiration rate was synchronized with stem volume increment rather than with monthly mean air temperature. The respiration rate, r, of individual trees increased with increasing tree dimensions, such as stem volume, v(S), and stem girth at the base of the live crown, G(B). The dependence of respiration rate on tree size was successfully represented by a power function. The r - v(S) dependence was rather stronger than the r - G(B) (2) dependence, especially toward the end of the growing season (from July to September). The observed respiration rate was almost the same as the respiration rate corrected for the monthly mean air temperature. The annual respiration of individual trees was directly proportional to their phytomass or to its increment. Although the annual respiration of individual trees decreased proportionally to the square root of the leaf mass, it decreased abruptly in the range close to the smallest sample tree. Combining the monthly relationship between respiration rate and stem volume with the tree size distribution in the stand, the stand aboveground annual respiration was estimated to be 20.4 Mg CO(2) ha(-1) year(-1) (= 12.5 Mg dry mass ha(-1) year(-1)) for an aboveground biomass of 17.4 Mg ha(-1) with an annual increment of 6.51 Mg ha(-1) year(-1), i.e., the stand aboveground annual respiration amounted to the equivalent of 72% of the biomass or to almost twice the biomass increment.
通过封闭立木法，对一片8年生日本扁柏（Chamaecyparis obtusa (Sieb. et Zucc.) Endl.）林分中的5棵样树的地上部分进行了为期一年的夜间呼吸测量，测量间隔为每月一次。呼吸速率从早春迅速上升至6月达到最大值，7月急剧下降，然后在秋冬季节逐渐下降。呼吸速率的季节变化与茎体积增加同步，而非与月平均气温同步。单株树木的呼吸速率r随树木尺寸的增加而增加，如茎体积v(S)和活冠基部的茎围G(B)。呼吸速率对树木大小的依赖性成功地用幂函数表示。r - v(S)的依赖性比r - G(B)的依赖性更强，尤其是在生长季节末期（7月至9月）。观测到的呼吸速率与经月平均气温校正后的呼吸速率几乎相同。单株树木的年呼吸量与其植物量或其增量成正比。虽然单株树木的年呼吸量与叶质量的平方根成比例下降，但在接近最小样树的范围内急剧下降。将呼吸速率与茎体积的月度关系与林分中的树木大小分布相结合，对于地上生物量为17.4 Mg ha(-1)、年增量为6.51 Mg ha(-1) year(-1)的情况，林分地上年呼吸量估计为20.4 Mg CO₂ ha(-1) year(-1)（= 12.5 Mg干质量 ha(-1) year(-1)），即林分地上年呼吸量相当于生物量的72%或几乎是生物量增量的两倍。
