重庆铁山坪3种常见树种的树干液流特征研究

Sap Flow Characteristics of Three Common Tree Species on Tieshanping Hill in Chongqing

2014年8-10月,应用热扩散式探针和自动气象站,对重庆铁山坪3种常见树种(马尾松、杉木和木荷)树干液流速率及相关气象因子进行了测定。结果表明:1不同月份晴天液流为典型的单峰曲线,昼高夜低,并存在轻微的午休现象,不同树种液流启动、达到峰值和较高速率保持的时间不同。雨天液流速率明显不同于晴天液流水平,且雨后可能出现根压导致的液流升高的情况。2除木荷8月液流平均日变化低于10月,各树种液流速率均为8月>10月>9月。3白天木荷液流速率高于马尾松和杉木,液流峰值持续时间木荷(4 h)>马尾松(2.5 h)>杉木(2 h)。4各树种液流速率与平均净辐射、空气温度呈显著正相关(P<0.01),与空气相对湿度普遍呈显著负相关(P<0.01),气象因子对液流的影响程度与树种和月份有着密切关系。

The sap flow velocity of Pinus massoniana,Cunninghamia lanceolata and Schima superba and related meteorological factors under natural secondary forest in Tieshanping,Chongqing were determined by using thermal dissipation probe method and Weather Hawk232 automatic weather stations,from August to October in 2014. The results showed that： The liquid flow of trees on sunny day showed a typical single peak curve in different months,with high daytime to low night,and a slight depression phenomenon,liquid flows of different species had different starting time,different peaks and the time- keeping. The flow rate of wet liquid is obviously different from that of the sunny day,and the increase of the liquid flow caused by root pressure may appear after the rain. The average daily variation of sap flow of Schima superba in August was lower than that in October,the tree sap flow rate were in August 〉 in October 〉 in September. The liquid flow rate of Schima superba on daytime was higher than that of Pinus massoniana and Cunninghamia lanceolata,the sap flow peak sustained time of Schima superba（ 4 h） 〉 Pinus massoniana（ 2. 5 h） 〉 Cunninghamia lanceolata（ 2 h）. The flow rate of each tree species was significantly positively correlated with the average net radiation,air temperature（ P 〈 0. 01）,but significantly negative correlation（ P 〈 0. 01） with the relative humidity of air.