摘要
应用热脉冲速度记录仪在宁夏固原六盘山地区研究了主要造林树种———华北落叶松的蒸腾耗水规律。结果表明 ,1 3a的单木液流量在生长季中后期 (7～ 1 0月份 )表现出明显的昼夜变化节律 ,夜间液流活动微弱且时断时续 ,其值一般在 0 0 0 0 0 8m3·h- 1 以下 ;白天随太阳辐射和空气温度升高而持续上升 ,其最大值可达 0 0 0 1 0 79m3·h- 1 ,树干径向不同位点液流速度的变化由外向里呈现出低—高—低的态势。用日累积液流量作为单木日蒸腾量的估计值 ,并用“截干测定”方法进行验证 ,结果说明两者的日变化曲线基本吻合 ,后者2 4h蒸腾量为 0 0 0 3 1 7m3,比前者高出仅 8 2 % ,这主要是因为热脉冲仪还难以准确地观测到较弱液流。同时 ,分别以胸径和边材面积作为空间纯量 ,在单木日蒸腾量估算的基准上通过尺度放大转换估计了整个林分的日蒸腾量 ,前者估计值为 0 64mm·d- 1 ,较后者低 0 0 5 1mm·d- 1 ,这与边材长度的确定缺乏足够高的精度有关。最后分析了单木蒸腾量和环境因子间的关系 ,发现太阳辐射强度、空气温度和相对湿度是影响单木日蒸腾量的三个主要环境因子 。
The sap flow of Larix principi-rupprechtii, which is one of the most principal species for afforestation in northwestern China, was researched by means of heat pulse method. The results indicated that the sap flow changed regularly from day to night in later growth season. In the night, it was very slow and the value was usually below 0.000 08?m 3·h -1,and became stronger with increasing of solar radiation intensity and atmosphere temperature in daytime, and the maximum could reach 0.001 079?m 3·h -1. The results also showed that the sap velocity of points of stem section from outer to inner accorded with the law that the velocity is slow-quick-slow. The daily transpiration of individual tree was estimated on the basis of calculation of daily cumulative sap flow, at the same time, the cut tree experiment was done to validate the value. The study showed that the results were not different significantly using two methods, and the later value (0.003 17?m 3·d -1) was 8.2% higher than the former, because the logger was not enough sensitive to record low sap flow. And the stand daily water use for transpiration was estimated by applying to DBH and sapwood area as two scalars to scale up based on individual tree measurement respectively. And the former value was 0.64?mm·d -1, which was 0.051?mm lower than the later. At last, the relationship between daily transpiration and environment factors was studied by correlation analysis. The result showed that solar radiation intensity, atmosphere temperature and relative humidity were three significant environmental factors to determine daily transpiration water use, and the regression equation was constructed accordingly.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2003年第2期1-7,共7页
Scientia Silvae Sinicae
基金
科技部社会公益研究专项资金项目"林业生态工程的水资源调节影响监测研究 ( 2 0 0 1-82 )资助 "
国家自然科学基金重点项目"干旱半干旱地区森林与水资源的相互影响及合理调控机理 ( 30 2 30 2 90 )"
国家"十五"科技攻关计划子课题"黄河上游黄土高原水源涵养型植
关键词
森林水文
林分蒸腾
尺度转换
环境因子
华北落叶松
Forest hydrology, Transpiration, Scaling up, Environmental factors, Larix principi-rupprechtii plantation
