Yokota Taketo, Hagihara Akio
Laboratory of Forest Ecophysiology, School of Agricultural Sciences, Nagoya University, Nagoya 464-01, Japan.
Tree Physiol. 1998 Jan;18(1):37-43. doi: 10.1093/treephys/18.1.37.
Respiration measurements of aerial parts of 18-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) trees were made under field conditions over three years to study changing relationships with tree age between respiration and phytomass, phytomass increment, and leaf mass. The relationship between annual respiration (r(a)) and phytomass (w(T)) was approximated by a proportional function (r(a) = aw(T)), where the proportional constant (a) decreased year by year. The effect of time on the relationship between annual respiration and phytomass of each sample tree was fitted by a power function. Respiration of the tree suppressed by the canopy decreased year by year, but respiration of the other trees increased slightly with age. The relationship between annual respiration and leaf mass was also approximated by a generalized power function. Excluding the suppressed tree, the relationship between annual respiration (r(a)) and the annual increment of aboveground phytomass (Deltaw(T)) was described by a proportional function (r(a) = 2.27Deltaw(T)), where the proportional constant, 2.27, was independent of sample tree and year, indicating that about 2.3 times of the annual aboveground phytomass increment equivalent was respired annually. For any tree, the time constant relationships between annual respiration and leaf mass and phytomass increment for different-sized trees were similar to the corresponding time continuum relationships. In contrast, the time continuum relationship between annual respiration and phytomass differed from the time constant relationship, indicating that respiration of less active woody tissue contributed significantly to aboveground respiration. Based on the relationship between tree size and annual respiration, annual aboveground stand respiration was estimated to be 25.0, 26.9, and 25.8 Mg(dm) ha(-1) year(-1) for the three consecutive years, respectively, and the corresponding aboveground stand biomass was 60.0, 69.0, and 76.8 Mg(dm) ha(-1).
在田间条件下，对18年生日本扁柏（Chamaecyparis obtusa (Sieb. et Zucc.) Endl.）树的地上部分进行了为期三年的呼吸测量，以研究呼吸作用与植物量、植物量增量和叶量之间随树龄变化的关系。年呼吸量（r(a)）与植物量（w(T)）之间的关系可用比例函数（r(a) = aw(T)）近似表示，其中比例常数（a）逐年下降。时间对每个样本树的年呼吸量与植物量之间关系的影响可用幂函数拟合。被树冠抑制的树的呼吸作用逐年下降，但其他树的呼吸作用随年龄略有增加。年呼吸量与叶量之间的关系也可用广义幂函数近似表示。排除受抑制的树后，年呼吸量（r(a)）与地上植物量年增量（Deltaw(T)）之间的关系可用比例函数（r(a) = 2.27Deltaw(T)）描述，其中比例常数2.27与样本树和年份无关，表明每年呼吸的量约为地上植物量年增量的2.3倍。对于任何一棵树，不同大小树木的年呼吸量与叶量和植物量增量之间的时间常数关系与相应的时间连续关系相似。相比之下，年呼吸量与植物量之间的时间连续关系与时间常数关系不同，这表明活性较低的木质组织的呼吸作用对地上呼吸有显著贡献。根据树大小与年呼吸量之间的关系，连续三年地上林分年呼吸量估计分别为25.0、26.9和25.8 Mg(dm) ha(-1) year(-1)，相应的地上林分生物量分别为60.0、69.0和76.8 Mg(dm) ha(-1)。
