华北落叶松夜间树干液流特征及生长季补水格局  

The characteristics of nocturnal sap flow and stem water recharge pattern in growing season for a Larix principis-rupprechtii plantation

作　　者：王艳兵[1,2] 德永军[1] 熊伟[2] 王彦辉[2] 李振华[2] 刘千[2,3] 

机构地区：[1]内蒙古农业大学林学院,呼和浩特010019 [2]中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室,北京100091 [3]甘肃农业大学资源与环境学院,兰州730070

出　　处：《生态学报》2013年第5期1375-1385,共11页Acta Ecologica Sinica

基　　金：林业公益性行业科研专项(201104005-02;200904056);"十二五"国家科技计划课题(2011BAD38B0503;2012BAD22B030102);国家自然科学基金(41071023)

摘　　要：在宁夏六盘山北侧半干旱区的叠叠沟小流域,采用热扩散探针法在2011年生长季监测了华北落叶松(Larix principis-rupprechtii)人工林的树干液流速率,分析了夜间树干液流和补水量的变化特征及与气象、土壤水分等环境因子的关系。结果表明:树干液流速率日变化表现为典型的单峰宽峰曲线,且整个生长季均存在微弱的夜间液流,一般表现为逐渐减小,特别是在晴天,且晴天的变幅显著大于雨天。除生长季中期雨天夜间液流平均速率显著高于晴天,生长季初期及末期雨天与晴天的差异并不显著。生长季内,夜间树干补水总量为11.03 mm,占总蒸腾量的7.22%;5月份的树干补水量最大(4.19mm),其他月份的树干补水量明显减小,在0.9—1.7mm的范围波动。但不同月份间的补水贡献率存在明显差异,表现为生长季末期(9、10月)>初期(5月)>中期(6—8月)。相关分析表明,日补水量与各气象因子关系不大,仅与降水量显著正相关(P<0.05),与土壤含水率、日间蒸腾量、日蒸腾总量极显著正相关(P<0.01)。夜间补水的月蒸腾贡献率与月均土壤含水率、月均气温、月均日间蒸腾量、月总蒸腾量等显著相关(P<0.05);而夜间补水的日蒸腾贡献率与日最高气温、日均气温、日间蒸腾量、日均饱和水汽压差、日总蒸腾量、日均太阳辐射强度、日最低气温、日均空气相对湿度、日降水量、土壤含水率等极显著相关(P<0.01),经逐步回归分析建立了日补水量蒸腾贡献率与环境因子的多元线性模型。To fully understand the forest transpiration processes and evaluate the contribution of nocturnal sap flow to total transpiration in dryland region, the sap flow velocity in the stems of 4 sample trees of a 30mx30m Larix principis-rupprechtii plantation was continually monitored with thermal dissipation probes （TDP） during the growing season （May to October） of 2011, at the semi-arid area （with an annual precipitation of 449 mm, but mostly concentrated in the summer months from July to September） of the north part of Liupan Mountain, NW China. Then, the sap flow density data measured in individual sample trees were used to calculate the sap flow amount in daytime, nighttime and whole day, and up-scaled to the stand level by using the index of sapwood area. Then, the dynamics of nocturnal sap flow and stem water recharge as well as their relations with environmental factors were analyzed. The daily variation of sap flow demonstrated a typical wide single-peak curve. The nocturnal sap flow existed in the whole growing season. The sap flow velocity in nighttime was notably lower than that in daytime and always fluctuated above zero. Furthermore, the nocturnal sap flow velocity decreased with time, and was significantly higher in the first half of night than that in the second half of night, especially for sunny days with higher transpiration and stem water deficit. Thus, the variation of nocturnal sap flow was significantly larger in sunny days than that in rainy days. The total amount of nocturnal water recharge in the stand studied was 11.03 mm during the whole growing season, which accounted for 7.22% of the total transpiration. The monthly stem water recharge and its ratio to total transpiration differed obviously in the months observed. The absolute stem water recharge was highest in May, with a value of 4.19 mm; but obviously decreased in other months and fluctuated in the range of 0.9--1.7 mm. However, the ratio of nocturnal water recharge to total transpiration was higher in the later period （

关 键 词：六盘山 华北落叶松 人工林 夜间液流 补水量 环境因子 

分 类 号：S791.22[农业科学—林木遗传育种]