【作者】 孔维健；

【导师】 周本智；

【作者基本信息】 中国林业科学研究院 ， 生态学， 2010， 硕士

【摘要】 本文在庙山坞自然保护区选择我国亚热带地区分布较典型的天然次生林和人工毛竹林两种森林类型,从森林植被冠层、林下灌木层、凋落物层等多层次研究了林内降雨分配规律和森林的水土保持功能,以及森林生态系统各个层次对水质的影响改善作用,同时探讨了林内降雨各分量与林外降雨量的关系,并进行了方程拟合,为不同森林类型涵养水源和水土保持等功能的客观评价提供了基础数据,同时也为天然林和人工林的可持续经营和改造提供了理论基础,具有十分重要的理论和现实意义。研究结果表明:（1）森林植被对降雨再分配具有显著效果,森林植被冠层、林下灌木层、凋落物层可有效截留降雨。其中人工毛竹林植被冠层截留率平均达14.5%,凋落物每次降水最大蓄水潜力0.98 mm;天然次生林植被冠层截留率平均达33.8%,林下灌木层截留率平均达7.0%,总截留率平均高达40.8%,凋落物每次降水最大蓄水潜力1.58 mm。天然次生林林冠截留降雨、凋落物蓄水潜力均大于人工毛竹林。（2）森林生态系统具有较好的水土保持功能,对减少产流量和产沙量具有较好效果。天然次生林和人工毛竹林地表径流系数分别为0.10%和0.20%,产生地表径流的最小降雨量分别是10.1 mm和7.0 mm;天然次生林和人工毛竹林径流泥沙量仅分别为0.262 kg/（hm²·mm）、1.034 kg/（hm²·mm）,几乎没有泥沙流失。天然次生林水土保持功能较人工毛竹林更好。（3）天然次生林、人工毛竹林林内降雨各分量与林外降雨量的关系均可用数学方程拟合,具有较高的相关性与显著性水平。其中穿透雨量、树干流量、地表径流量与林外降雨量用线性方程拟合最佳,而穿透雨率、树干茎流率、地表径流系数与林外降雨量用对数方程拟合最佳。林冠截留量/率与林外降雨量呈幂函数关系。树干茎流与树木胸径正相关。（4）森林生态系统植被冠层、凋落物层、森林土壤和岩石改变了降雨的化学成分,对水质有一定的改善作用。从大气降雨到地表径流,除pH值外,几乎所有检测指标都呈上升趋势,这主要体现大气降雨对林冠层和凋落物层的淋溶作用。到流域出口,NO₃^-、NH₄⁺、K⁺、Na⁺浓度大幅降低,说明森林土壤在保持NO₃^-、NH₄⁺、K⁺、Na⁺方面有“调蓄库”的作用。Ca²⁺、Mg²⁺浓度升高,可能主要是土壤、岩石中Ca、Mg的溶解引起。总之,天然次生林和人工毛竹林在截留降雨、涵养水源、保持水土、改善水质等方面发挥着十分重要的作用。但相比较而言,天然次生林林内降雨分配效果更好,水土保持功能更强。更多还原

【Abstract】 The precipitation partition of two subtropical typical forests （natural secondary forest and artificial bamboo forest） in Miaoshanwu Nature Reserve in Zhejiang was studied. The rainfall interception of varied layers of the tree canopy, shrub and litter was measured, with the function of soil and water conservation, and the effects of different components of the forest ecosystem on water quality discussed. The equations were established to simulate the relationship between the precipitation partitioning and the atmosphere precipitation. This study is of great theoretical and practical significance, as it provides the basic data for the objective evaluations on the function of water resources conservancy, as well as soil and water conservation of different forest types, and also it provides a theoretical foundation for sustainable management and improvement of natural forests and plantations. The results are as follows:（1） The forests are effective on precipitation partitioning, with the forest vegetation canopy, understory shrub layer and litter layer intercepting rainfall to a varied extent. The artificial bamboo forest canopy interception rate is 14.5%, and the litter maximum water-holding capacity is 0.98 mm; while the natural secondary forest canopy interception rate is 33.8%, understory shrub layer interception rate is 7.0%, with the total interception rate reaching 40.8%, and the litter maximum water-holding capacity is 1.58 mm. It can be seen that the canopy interception and the litter water-holding capacity of natural secondary forest are better than that of artificial bamboo forest.（2） The surface runoff and erosion sediment of forest ecosystems are very low, implying that the function of soil and water conservation is pretty good. The runoff coefficients of natural secondary forest and artificial bamboo forest are only 0.10% and 0.20%, and the minimum precipitation generating the surface runoff are 10.1 mm and 7.0 mm respectively. The erosion sediment of natural secondary forest and artificial bamboo forest are as low as 0.262 kg/（hm²·mm） and 1.034 kg/（hm²·mm） respectively. The function of soil and water conservation of natural secondary forest is better than that of artificial bamboo forest.（3） The relationship can be perfectly simulated by mathematical equations between the precipitation partitioning and the atmosphere precipitation either for natural secondary forest or artificial bamboo forest with a high relevance and significance level. The linear equation is the best to simulate the relationship between the throughfall, stem flow as well as surface runoff and the atmosphere precipitation, while the throughfall ratio, stem flow ratio and runoff coefficient with the atmosphere precipitation are best fit by logarithmic equation. A power regression exist between the canopy interception/ratio and precipitation; the stemflow is positively correlated with tree diameter at breast height.（4） Vegetation canopy, litter layer, soil and rock in forest ecosystems have changed the chemical composition of precipitation and certainly improved water quality. All Indexes for water quality tend to increase from the atmosphere precipitation to the surface runoff except pH value, which mainly reflect the leaching of precipitation on the forest canopy and litter layer. NO₃^-, NH₄⁺, K⁺, and Na⁺ significantly decrease, indicating that forest soil has "Storage tank" role in maintaining NO₃^-, NH₄⁺, K⁺, and Na⁺, while Ca²⁺ and Mg²⁺ content in outlet flow increase due to the dissolution of Ca and Mg in soil and rock.In conlcusion, natural secondary forest and artificial bamboo forest play an important role in precipitation interception, waer resources conservancy, soil and water conservation, and water quality improvment. The hydrological effect of natural secondary forest is better than that of artificial bamboo forest, and the function of soil and water conservation of natural secondary forest is also more powerful.更多还原