Yokota T, Hagihara A
Laboratory of Forest Ecophysiology, School of Agricultural Sciences, Nagoya University, Nagoya 464-01, Japan.
Tree Physiol. 1995 Jun;15(6):387-92. doi: 10.1093/treephys/15.6.387.
Aboveground respiration of five 8-year-old trees of field-grown hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) was nondestructively measured at monthly intervals over 1 year with an enclosed standing tree method. The relationship between monthly specific respiration rate and monthly mean relative growth rate at the individual tree level was described by a linear equation. During the dormant season, respiration was used mainly for maintenance purposes, whereas during the growing season, more than 40% of the respiration was used for growth purposes, i.e., 60 to 70% in May. We conclude that annual maintenance and growth respiration of a tree are directly proportional to the aboveground phytomass and its annual increment, respectively. The maintenance coefficient was estimated to be 0.504 +/- 0.039 (SE) kg kg(-1) year(-1), indicating that the amount respired for maintaining already existing phytomass was equivalent to about half of the existing phytomass. The growth coefficient was estimated to be 0.772 +/- 0.043 (SE) kg kg(-1), indicating that the amount respired for constructing new phytomass was equivalent to about three-fourths of the annual phytomass increment. The annual stand maintenance and growth respiration were, respectively, 8.8 Mg ha(-1) year(-1) for an aboveground biomass of 17.4 Mg ha(-1) and 5.0 Mg ha(-1) year(-1) for an annual stand aboveground biomass increment of 6.5 Mg ha(-1) year(-1). About two-thirds of the total respiration was used to maintain already existing biomass, and about one-third was used to construct new biomass.
采用封闭立木法，在1年的时间里每月对5株8年生野外种植的日本扁柏（Chamaecyparis obtusa (Sieb. et Zucc.) Endl.）地上部分的呼吸作用进行无损测量。通过线性方程描述了单株树木每月比呼吸速率与每月平均相对生长速率之间的关系。在休眠季节，呼吸作用主要用于维持生命活动，而在生长季节，超过40%的呼吸作用用于生长，即5月份为60%至70%。我们得出结论，树木的年维持呼吸和生长呼吸分别与地上植物量及其年增量成正比。维持系数估计为0.504±0.039（标准误）kg kg⁻¹ 年⁻¹，这表明用于维持现有植物量的呼吸量约相当于现有植物量的一半。生长系数估计为0.772±0.043（标准误）kg kg⁻¹，这表明用于构建新植物量的呼吸量约相当于年植物量增量的四分之三。对于地上生物量为17.4 Mg ha⁻¹ 的林分，年维持呼吸和生长呼吸分别为8.8 Mg ha⁻¹ 年⁻¹，对于年林分地上生物量增量为6.5 Mg ha⁻¹ 年⁻¹ 的情况，生长呼吸为5.0 Mg ha⁻¹ 年⁻¹。总呼吸量的约三分之二用于维持已有的生物量，约三分之一用于构建新的生物量。
