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林业科学 ›› 2017, Vol. 53 ›› Issue (10): 154-159.doi: 10.11707/j.1001-7488.20171017

• 研究简报 • 上一篇    下一篇

各径级马尾松树干CO2释放速率及其温度敏感性

涂洁, 樊后保, 王勇刚, 李志鹏   

  1. 南昌工程学院生态与环境科学研究所 江西省退化生态系统修复与流域生态水文重点实验室 南昌 330099
  • 收稿日期:2016-05-22 修回日期:2017-08-28 出版日期:2017-10-25 发布日期:2017-11-29
  • 基金资助:
    国家自然科学基金项目(31260172)。

Stem CO2 Efflux Ratio of Pinus massoniana of Various DBH Classes and Its Sensitivity to Temperature

Tu Jie, Fan Houbao, Wang Yonggang, Li Zhipeng   

  1. Research Institute of Ecology & Environmental Sciences, Nanchang Institute of Technology Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology Nanchang 330099
  • Received:2016-05-22 Revised:2017-08-28 Online:2017-10-25 Published:2017-11-29

摘要: [目的]探明退化红壤区重要先锋树种马尾松不同径级间树干CO2释放速率(FCO2)的差异及其温度敏感性,以期为正确评价马尾松人工林树干呼吸对森林生态系统的碳汇贡献提供基础数据。[方法]采用全自动便携式光合仪与自制PVC呼吸环相连,对马尾松人工林4个径级(15.9~17.9,18.9~20.5,22.8~24.8和27.1~29.8 cm)共12棵样树的树干CO2释放速率FCO2进行为期1年的活体原位监测,并同步监测树干1 cm深处温度,分析FCO2的季节变化及径级间差异,并建立FCO2与树干温度的指数函数模型。[结果]4个径级FCO2均呈现出一致的单峰季节性变化趋势,生长季FCO2极显著高于非生长季(P<0.01),7月份最高,1月份最低,且生长季各径阶样树FCO2间差异显著(P<0.01);4个径级FCO2与树干温度均存在显著的指数关系,但两者间的回归模型及其决定系数因径阶而异,表现出大径阶FCO2与树干温度的相关性高于小径阶;4个径级树干呼吸的温度敏感系数(Q10)间差异不显著(1.47~1.64);马尾松FCO2与DBH显著正线性相关(R2=0.89),表明DBH可作为针叶树种FCO2预测和推算的一个简便实用指标。[结论]在采用局部通量法进行森林生态系统树干呼吸估算时,应同时考虑FCO2的季节变化及径级差异,以提高估算精度。

关键词: 马尾松, 树干温度, 树干CO2释放速率, 径级

Abstract: [Objective] Stem CO2 efflux rates of various DBH classes and its sensitivity to temperature were investigated of the important pioneer tree species Pinus massoniana in the degraded red soil region. The aims of this study were to providefundamental data for evaluating the carbon sink contribution of stem respiration from Pinus massoniana plantation to the ecosystem.[Method] We conducted year-round in situ chamber measurements of FCO2 on twelve stems of Pinus massoniana using an automated, portable gas-exchange system (LC PRO-SD, ADC BioScientific Ltd., Hoddesdon, UK), which was equipped with an infrared gas analyzer and a transparent plexiglas cuvette. The sample trees were selected from four DBH classes (15.9-17.9, 18.9-20.5, 22.8-24.8, and 27.1-29.8 cm) with three replicates. At least 24 h prior to measurements, loose bark was removed from the surface of measurement and then collars were mounted horizontally on the north-facing stems at about 135 cm above-ground with 100% silicone sealant. During the process of measurements, the chamber was wrapped with aluminum foil to avoid excess heating by direct sun exposure. Stem temperature at 1 cm depth (Ts) were recorded synchronously. The measurements were conducted from 8:00 to 17:00 for the selected days each month between January and December in 2015 to ensure that the temperature range of data was collected as widely as possible. The temporal fluctuations of FCO2 and difference between various DBH classes were analyzed. And the exponential regression models were also established between FCO2 and Ts.[Result] There was clear seasonality in FCO2 for four diameter classes following similar remarkable single-peak patterns, with the maximum values occurring in July and the minimum in January. Obviously, the monthly FCO2 values were significantly higher(P<0.01)during the fast-growing season than in the slow-growing season. The values of FCO2 differed significantly(P<0.01)among various DBH classes during the growing season but not in the non-growing season. Significant exponential relationships were found between FCO2and Ts, with the correlations of determination higher in the bigger DBH classes than those in the smaller DBH classes. Furthermore, the values of temperature sensitivity (Q10) for four diameter classes varied from 1.47 to 1.64, which were within the range of values previously reported for most conifers. Additionally, FCO2were significantly correlated positively with DBH(R2=0.89), suggesting that DBH could be used as a proxy for predicting stem respiration for conifers.[Conclusion] Therefore, the temporal variations in FCO2and difference between various DBH classes should be simultaneously considered when estimating forest carbon budgets so as to improve the accuracy of evaluation.

Key words: Pinus massoniana, stem temperature, stem CO2 efflux ratio, diameter classes

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