【作者】 马长明；

【导师】 袁玉欣；

【作者基本信息】 河北农业大学 ， 森林培育， 2004， 硕士

【摘要】 本文以北京市官厅库区水源涵养林的主要造林树种：小叶杨、刺槐为研究对象，采用当前国内外最先进的热脉冲式树干边材液流测定技术和热扩散式树干边材液流测定探针（TDP）测定技术，从叶片和单株水平上探讨了刺槐和小叶杨的蒸腾耗水特性以及它们与环境因子之间的影响机理，其结果不仅可为更精确地估计生态用水定额提供科学依据，而且也可为该区域这两种树种的选择及其合理林分的密度起到一定的指导作用。该研究的主要结论如下： 1)研究了小叶杨和刺槐树种的叶片蒸腾耗水规律：叶片蒸腾速率随着辐射强度的增强而增强，08：00，小叶杨叶片蒸腾速率为77.66g／m²·h，而刺槐仅为20.98g／m²·h；大约在12：00-15：00达到峰值，小叶杨和刺槐分别为229.73g／m²·h和143.94g／m²·h。之后又逐渐减小。在本试验条件下，对于小叶杨，辐射强度和空气温度日变化对叶片蒸腾速率日变化的影响较为显著，10cm土壤温度、相对湿度和风速对叶片蒸腾速率日变化的影响不明显：而对于刺槐，其叶片蒸腾速率与太阳辐射相关性较好，与空气温度、空气湿度、土壤温度和风速日变化与叶片蒸腾速率之间无显著性相关。 2)研究了小叶杨和刺槐树种的树干边材液流的日变化、连日变化以及月变化进程，发现小叶杨和刺槐树干液流日进程均呈现出明显的昼夜变化规律，通常白天07：00～08：00液流开始上升，以后，随着辐射强度的增强，气温、土壤温度的增加，使得液流速率不断上升，并且在12：00～15：00左右达到其峰值，然后开始下降，19：00左右速度变慢，直至来日日出之前达到最低值；也证明夜间有微弱液流存在，这是树体水分恢复和储水阶段，以备来日耗水之用。 3)研究了边材液流随方位、插入位点和径阶的变化规律，探明在树干的不同方位，液流速率存在有一定差异，规律为：西侧＞北侧＞南侧＞东侧；树干不同位点的液流速率在昼夜变化趋势及峰形一致，但其峰值存在有一定差异，整个树干径向不同位点的液流速率由外向内呈下降趋势；边材液流速率随径阶的增大无明显规律，但液流通量和耗水量随径阶的增大而增大。 4)通过对树干边材液流规律的测定发现，刺槐的边材率较低，只有14.8％，而小叶杨边材率为81.8％。 5)本文分析了不同气象因子对液流的影响方式，建立了两树种边材液流速率与微气象因子的多元线性模型，并表现出良好的相关性(小叶杨：Vs＝9.467—0.109RH+0.322Ta+4.108×10^-3ESR—0.268Ts，R²=0.963；刺槐：Vs=6.033×10^-3ESR+0.749Ta—9.502，R²=0.956)。 6)以小叶杨树种为例，利用其边材宽度与胸径之间良好的相关性（Ysy=2.87+0.23×Xsy，R²=0.97），在热扩散技术测定的单株耗水量的基础上，完成了单株耗水到林分耗水的空间尺度放大。更多还原

【Abstract】 The two tree water consumption characteristics, Populus simonii and Robinia pseudoacacie, and the interactions mechanism with environment factors were both studied at the level of leaf and singletree in terms of the modern technology of heat pulse sap flow and thermal dissipation sap flow probe (TDP). The two main purposes of study are to provide the science evidence in estimating the ecologic water consumption rules and to arrange better densities of the two tree species stand. The main suggestions are showed as below.1) It shows that the leaf transpiration rates of the two tree species increased with the radiation and they, for example, were 77.66g/m2 . h for Populus simonii and 20.98g/m2 . h for Robinia pseudoacacie at 8:00, but were 229.73g/m2 . h for Populus simonii and 143.94g/m2 . h for Robinia pseudoacacie at 12:00 ~ 15:00, which were the peak points of the two tree species respectively. Then, the transpiration rates decreased smoothly. The transpiration rates of reaction to environment factors of the two tree species were different in the condition, which the radiation, air temperature had significantly effect on Populus simonii, but the soil temperature in 10cm, relative humidity and wind speed had little effect on it. For Robinia pseudoacacie, on the other hand, the leaf transpiration velocity was well relative with solar radiation, but there were not significant different between the leaf transpiration velocity and the air temperature, relative humidity, soil temperature and wind speed.2) The normal rules of sap flow of the two tree species from day to night were that it began from 7:00-8:00, and increased smoothly with the strength adding of solar radiation, air temperature and soil temperature. When it reached peak at 12:00-15:00, the value became to decrease gradually. At 19:00, it decreased more slowly, but till daybreak, it get the minimum point. The interest phenomena found was that there was sap flow in nighttime, although it was faintly, which would be stem water restoration and storage for day transpiration.3) It is demonstrated the sap flow values probed in the stem were varieties in different directions. The value sequence was westward > northward > southward > eastward. At different directions of the stem, the change rules of sap flow rates, from daytime to nighttime, were the similarity, but the only different point was the value of peak. From transect of stem, the sap flow rates decreased gradually from sapwood to duramen. Also, there was not distinct regulation between the sap flow velocity and the diameter, but thesap flux density and the water consumption were increasing with tree diameter.4) According to the measurement on sap flow of the two tree species, the sapwood of Robiniapseudoacacie was smaller than Populus simonii, which were 14.8% and 81.8%.5) Based on the analysis, the multi-linearity models of the two tree species were built between sap flow rate and micrometeorological factors, which showed a significant correlation (Populus simonii: Vs = 9.467 - 0.109RH+0.322Ta + 4.108 X 10 ~ 3ESR -0.268Ts, R2=0.963; Robinia pseudoacacie: Vs=6.033 X 10-3ESR+0.749Ta- 9.502, R2= 0.956)6) With the Populus simonii as example, the significant correlation between the sapwood width and tree diameter (Ysy=2.87+0.23 XXsy, R2=0.97), the stand water consumption models were successfully established from singletree water consumption monitored by thermal dissipation technology.更多还原