【作者】 赵勇；

【导师】 张胜利；

【作者基本信息】 西北农林科技大学 ， 生态环境工程（专业学位）， 2015， 硕士

【摘要】 南水北调工程是我国为解决北方水资源短缺而实施的一项重大战略工程(包括东线、中线和西线工程),秦岭南坡是其中线工程的重要水源区,多数地方被森林覆盖。森林枯落物是森林生态系统的重要组成部分,具有水土保持和涵养水源的作用,因而对枯落物的持水性能进行研究具有重要意义。20世纪60年代,该地区森林曾被大量采伐,现有森林植被主要是恢复之后天然次生林,森林生长减缓。为促进林木的生长,需要对其进行合理间伐。本研究针对秦岭山区主要森林类型,选择其中华山松林、油松林和锐齿栎林,通过测定不同间伐强度下这三种森林类型林下枯落物的累积量、最大持水率、最大持水量和吸水速率,采用对比分析的方法,探讨了枯落物的持水特点、不同森林类型枯落物的持水性能、以及间伐强度对枯落物持水性能的影响。得出主要结论如下:(1)随间伐强度增大,华山松林、油松林和锐齿栎林枯落物累积量均呈逐渐减小趋势:华山松林枯落物的累积量由未间伐时的27.680 t/hm2逐渐减少至间伐强度为20%时的17.826 t/hm2;油松林枯落物由29.532 t/hm2逐渐减少为间伐强度为25%时的19.072t/hm2;锐齿栎林枯落物由33.325 t/hm2逐渐减少为间伐强度为20%时的21.904 t/hm2。枯落物累积量以锐齿栎林最大,油松林次之,华山松林最小;同一林地枯落物的不同层次之间,枯落物半分解层累积量大于未分解层累积量。(2)不同间伐强度下,华山松林枯落物未分解层最大持水率在217.742%~235.385%,半分解层在249.586%~273.230%;油松林枯落物未分解层最大持水率在218.232%~237.163%,半分解层在259.224%~293.848%;锐齿栎林枯落物未分解层的最大持水率在231.628%~260.998%,半分解层在305.109%~340.498%。三种森林类型枯落物不同层次之间,半分解层最大持水率均大于未分解层的。在各间伐强度下,锐齿栎林枯落物半分解层最大持水率,均大于油松林和华山松林。在同一林地枯落物不同层次之间,半分解层枯落物最大持水率大于未分解层的。(3)各森林类型枯落物未分解层和半分解层持水量均随吸水时间延长而增大。各森林类型枯落物未分解层、半分解层持水量与吸水时间之间存在对数函数关系,相关系数均超过0.9。(4)华山松林、油松林和锐齿栎林枯落物未分解层、半分解层的平均吸水速率在0-2h时最大,2h之后逐渐变缓,10h后,吸水速率趋于稳定。吸水速率与吸水时间之间存在幂函数关系,相关系数均超过0.99。三种森林类型林下枯落物不同层次之间,半分解层的吸水速率大于未分解层的。(5)随间伐强度增大,华山松林、锐齿栎林枯落物最大持水量呈逐渐减小趋势;油松林枯落物最大持水量以未间伐时最大,间伐强度为10%时次之,其后依次为间伐强度为5%、15%、20%和25%的林地。三种森林类型,林下枯落物最大持水量由大到小分别是:锐齿栎林、油松林、华山松林。以最大持水量衡量枯落物持水能力,锐齿栎林最优;三种森林类型枯落物持水能力均以未间伐时最优。更多还原

【Abstract】 The south to North Water Diversion Project in our country is important and strategic to resolve the shortage of water resources problem in the north(including East, middle and West Routes). The southern slope of the Qinling mountain is a major water source area among those routes, most of which are covered by forests, thus, the hydrological function of the forests have big influence on the water quality in this area. Forest litter is an important part of forest ecosystem playing a role of soil retention and water conservation, so it is meaningful to study the water holding capacity of litter under trees, The forests in this area was heavily cut down in the 1960 s, the existing forest are mainly man-made forest and natural forest after resumption. After 50 years of growth, the forests growth become slowly, a reasonable intervals to cut down trees is needed to promote the growth of trees.This research aimed at main forest types in Qinling mountain area, forest types of Pinus armandii.,Pinus tabuliformis and Quercus aliena var.acuteserrata.are choosen as subject investigated. By determination of forest litter cumulants, maximum water holding rate, maximum holding capacity and water absorption rate of the three types forest mentioned above at different thinning intensities, using comparative analysis method to analyse litter water holding characteristics, water holding capacity of different types of forest litter and the effect of thinning intensities on it, finally, the conclusions were obtained as follows:(1). With increasing thinning intensity, forest types of Pinus armandii., Pinus tabuliformis and Quercus aliena var.acuteserrata.showed a decreasing trend. With 20% thinning intensity treatment, Pinus armandii. forest litter cumulants decreased from 27.680 t/hm2 to 17.826 t/hm2 gradually; Pinus tabuliformis forest litter cumulants reduced from 29.532 t/hm2 to 19.072 t/hm2 steadily; Quercus aliena var.acuteserrata changed from 33.325 t/hm2 to 21.904 t/hm2. Comparing the three forest types, Quercus aliena var.acuteserrata presented the maximum cumulants forest litter, followed by Pinus tabuliformis and Pinus armandii. successively. What’s more, semi-decomposed litter cumulants were more than non-decomposed at the different layers in the same litter.(2). In different thinning intensities of forest types, for Pinus armandii forest, the maximum water holding rate of non-decomposed layer of litters was 217.742%~235.385%, semi-decomposed layer was 249.586%~273.230%; for Pinus tabuliformis forest, the maximum water holding rate of non-decomposed layer of litters was 218.232%~237.163%, semi-decomposed layer was 259.224%~293.848%; for Quercus aliena var.acuteserrata forest, the maximum water holding rate of non-decomposed layer of litters was 218.232%~237.163%, semi-decomposed layer was 305.109%~340.498%. Between different layers of forest litter in various types of forest, the maximum water holding rate of semi-decomposed layer of litters was more than non-decomposed layer always. For the three forest types, the maximum water holding rate of semi-decomposed layer of litters Quercus aliena var.acuteserrata forest was greater than Pinus armandii.,Pinus tabuliformis forest under any thinning intensities conditions. And, the maximum water holding rate of semi-decomposed litter was more than non-decomposed at the different layers in the same litter.(3). Water holding capacity type of both non-decomposed and semi-decomposed layers of litters was increased as time prolonged in various forest litters. There was a logarithmic relationship between water absorption time and water holding capacity of non-decomposed and semi-decomposed layers in various forest litters, most of the correlation coefficient were more than 0.9 using regression models, showing good fitting result.(4) The average water absorption rate reached at biggest at 0-2h, became slowly after 2h and tended to be stable when the time was 10 h both in non-decomposed and semi-decomposed layers of litters of the three types of forests of Pinus armandii.,Pinus tabuliformis and Quercus aliena var.acuteserrata.There was a power function relationship between water absorption rate and absorption time, most of the correlation coefficient were more than 0.9 using regression models, showing good fitting result. And, the water absorption rate of semi-decomposed litter was more than non-decomposed at the different layers of litters in the three types of forest.(5). With increasing thinning intensity, the maximum water holding capacity of Pinus armandii and Quercus aliena var.acuteserrata forests showed a trend of decreasing gradually. The maximum water holding capacity of Pinus tabuliformis forests presented the biggest without thinning intensity treetment, and sequenced as 10%, 5%, 15%, 20% and 25% intensities successively with thinning intensity treatment. Among the three forest types, the biggest water capacity were Quercus aliena var.acuteserrata, Pinus tabuliformis and Pinus armandii forests in descending order.With the maximum water holding capacity to measure water holding capacity of forest litter, Quercus aliena var.acuteserrata forests was optimal. All the three forest types presented a good statement with litters without thinning indensity.更多还原