【作者】 刘宇；

【导师】 张洪江；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2014， 硕士

【摘要】 晋西黄土丘陵区生态系统比较脆弱,严重的水土流失是该区面临的一个主要问题,而植被恢复是治理该区水土流失的根本性途径；研究该地区典型人工林的蒸腾耗水规律,对于深入了解和调控林木水分关系、选择合适的造林树种、优化防护林体系以及空间配置等都具有现实的指导意义。本文以位于山西省中阳县黄土丘陵区典型水土保持树种油松和刺槐为研究对象,研究了其蒸腾特性并最终估算出了油松与刺槐的林分耗水量。主要研究结论如下：(1)油松、刺槐边材液流速率日变化均呈现出十分明显的昼夜规律,液流速率通常在5：00至7：00开始上升,并在中午前后达到峰值,然后开始下降直至次日清晨之前达到最低值。夜间仍有微弱液流存在,但是强度远低于白天。其中刺槐液流启动时间早于油松,且液流峰值高于油松液流峰值。(2)不同天气条件下林木边材液流速率变化规律差异较大,大小规律为：晴天>多云>阴天,阵雨天气下,油松、刺槐液流速率均会在降雨时急剧下降,在降雨结束后液流速率再次上升。(3)油松与刺槐边材液流速率在2013年6-10月之间月变化规律一致,液流速率随月份的变化趋势均为先上升后下降,均在8月份达到日均液流速率的最大值,证明油松、刺槐在该月蒸腾耗水作用最为强烈。(4)油松、刺槐边材液流速率与太阳辐射强度、水汽压差、空气相对湿度、空气温度均表现出了极显著的相关关系,与风速表现出了显著的相关关系,证明这些都是影响蒸腾的因子。(5)油松、刺槐不同径阶日均蒸腾耗水量大小关系为：油松16cm>12cm>8cm,刺槐17cm>13cm>9cm>5cm,说明胸径较大的树木一般日蒸腾量较大,树木形态对树木的蒸腾量有一定的影响。(6)2013年6-10月油松的各月的林分耗水量分别为11.24mm、12.45mm、19.32mm、14.09mm、12.10mm,油松林分耗水量总和为69.20mm；刺槐各月的林分耗水量分别为13.01mm、13.47mm、15.92mm、9.55mm、8.93mm,刺槐林分耗水量总和为60.87mm,两种典型林分的蒸腾耗水量均小于各月同期的降雨量,且刺槐的林分耗水量小于油松的林分耗水量。更多还原

【Abstract】 The loess hilly area of west Shanxi is characterized by its fragile ecosystems. Severe soil erosion is one of the major ecological problems in this region. Sustainable restoration of vegetation is the key approach to the control of soil erosion. It is critically important to study the transpiration of the two typical forests because it will be significant in regulating plant water relations, selecting proper afforestation species. This paper selected Pinus tabulaeformis Carr. and Robinia pseudoacacia L. as the research object, we also studied the transpiration characteristics of them and finally total transpiration of forest stand was estimated. The main conclusions are as follows:(l)The diurnal variation of sap flow velocity for Pinus tabulaeformis Carr. and Robinia pseudoacacia L. was analogous and apparent. Commonly the starting time is between5:00and7:00, and it will reach its peak during the noon. The lowest sap flow velocity appeared in the morning. The start time of sap flow velocity for Robinia pseudoacacia L. was earlier than Pinus tabulaeformis Carr. and the peak of Robinia pseudoacacia L. was also higher.(2)The order of sap flow velocity under different weather conditions is:sunny>cloudy>overcast. The sap flow velocity of Pinus tabulaeformis Carr. and Robinia pseudoacacia L. decreased rapidly when showery rain appeared. When the rain ended, sap flow velocity rose again.(3)During June and October, the monthly variation of sap flow velocity was basically the same. Sap flow velocity increased at the beginning and reached its peak in August, which proved that transpiration was the most severely in August. Sap flow velocity would decrease after August.(4)We found that the sap flow velocity was highly significantly correlated with solar radiation, vapor pressure deficit and relative air humidity. Also sap flow velocity was significantly related with wind speed. These environmental factors all affected the transpiration.(5)Mean diurnal transpiration order for the two different diameter classes were:Pinus tabulaeformis Carr.,16cm>12cm>8cm.Robinia pseudoacacia L.,17cm>13cm>9cm>5cm.We concluded that forests with bigger diameter at breast height had higher transpiration.(6)The monthly forest stand transpiration of Pinus tabulaeformis Carr. were11.24mm,12.45mm,19.32mm,14.09mm,12.10mm for each month, the total was69.20mm.The forest stand transpiration for Robinia pseudoacacia L. were13.01mm,13.47mm,15.92mm,9.55mm,8.93mm for each month, with total60.87mm. So the transpiration was less than the rainfall and the forest stand transpiration of Robinia pseudoacacia L. was less than the other one.更多还原