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树干呼吸是森林碳平衡估计中的一个重要项目同时还能够显示树木的活力。对于如何准确估计森林树干呼吸释放CO2总量还存在争论。在本项研究中,2001~2002连续两年在一个33年生的兴安落叶松(Larix gmelini Rupr.)人工林内对树干呼吸进行了测定,同时测定了不同高度树干呼吸、呼吸的日变化、同龄落叶松林内不同个体的树干呼吸以及相关生长状态因子、水分因子和温度因子。结果显示:1)树干上部的呼吸速率在不同季节都高于下部呼吸速率,树干温度的差异能够一定程度上解释这种差异;2)树干呼吸有午间降低的现象,上午的测定结果树干温度与树干呼吸速率紧密相关,而下午则温度依赖性很小,土壤、空气、小枝木质部水势、叶片蒸腾速率和气孔导度都显示下午植物水分亏缺下午较上午严重,呼吸的这种上下午温度相关性的差异可能受这种水分亏缺的影响;3)在同龄林内,树木个体生长状态包括平均生长速率和树冠投影面积与树干呼吸速率有显著相关关系,而树干温度与之相关性很小。幂指数模型和S曲线模型能够产生较好的拟合效果;4)树干呼吸季节变化明显,7月份出现最大值,但同一月份的年间差异较大。自然指数模型能够较好地拟合温度与树干呼吸的季节变化规律。Q10值在2.22 (2001年)和3.53 (2002年)之间,与以往研究的结果相当。从以上?
Trunk breathing is an important project in the estimation of forest carbon balance and can also show the vitality of trees. There is still debate about how to accurately estimate the total amount of CO2 released by the trunk of a forest to breathe. In this study, tree stem respiration was measured in a 33-year-old Larix gmelini Rupr. Plantation for two years in succession from 2001 to 2002. Diurnal variations of respiration and respiration of tree trunks at different altitudes were also measured. Trunk respiration and related growth status factors, water factors and temperature factors of different individuals in pine forests. The results showed that: 1) the upper part of the trunk respiration rate in different seasons are higher than the lower part of the respiration rate, the differences in trunk temperature can explain this difference to some extent; 2) trunk respiration decreased midday, the measured results of the morning trunk temperature and Trunk respiration rate was closely related to the afternoon temperature was very small, soil, air, branchlet xylem water potential, leaf transpiration rate and stomatal conductance showed that afternoon plant water deficit afternoon than in the morning, breathing this morning and afternoon temperature-related The difference of sex may be affected by this water deficit; 3) In the same age, the individual growth status of trees, including the average growth rate and canopy projected area have a significant correlation with the trunk respiration rate, but the correlation between trunk temperature and it is very small. The exponential model and the S-curve model can produce good fitting results; 4) The trunk respiration season changes obviously, with the maximum in July, but the difference in the same month is quite different. Natural index model can better fit the seasonal variation of temperature and trunk respiration. The Q10 value was between 2.22 (2001) and 3.53 (2002), comparable to previous studies. From above?