【作者】 刘延惠；

【导师】 王彦辉；

【作者基本信息】 中国林业科学研究院 ， 生态学， 2011， 博士

【摘要】 为在定量了解西北干旱缺水地区森林植被的生长固碳与耗水关系的基础上准确评估森林植被的固碳功能,并为科学指导森林植被与水资源的综合管理提供理论与技术支持,于2009年生长季在宁夏六盘山南部的香水河小流域,采用树干解析、样地植被与土壤调查、树木年轮分析、热扩散探针测定树干液流、树干径向变化记录仪测定径向生长等方法,开展了相关测定和研究。主要结论如下:1.典型植被类型的群落生物量建立了华北落叶松、桦木各器官（干、枝、皮、叶、根）的生物量与其胸径、树高的统计关系;建立了种类混合的灌木各器官（枝干、叶和根）生物量与地径的统计关系。各植被类型的平均生物量（t/hm²）为:森林（78.37）>灌丛（20.77）>草甸（2.29）>草地（1.07）。其中森林的生物量依次为华山松林（102.70）>桦木林（84.42）>山杨林（79.97）>华北落叶松人工林（58.37）>稀疏次生林（44.91）,乔木层、灌木层和草本层的生物量比例分别为91.04、8.09和0.87%;各器官生物量比例（%）对乔木层为:干（54.06）>枝（21.04）>根（16.92）>皮（5.34）>叶（2.65）,对灌木层为枝干（62.68）>根（30.55）>叶（6.77）,对草本层为地上茎叶（58.82）>根（41.18）。各类森林的枯落物现存量（t/hm²）平均为12.56,大小依次为华北落叶松人工林（18.21）>华山松林（11.99）>桦木林（10.90）>山杨林（7.67）>稀疏次生林（7.06）,均远大于灌木林（3.13）、草甸（0.82）和草地（0.49）的枯落物量。2.植被含碳率乔木全株平均含碳率为52.22%,各树种含碳率（%）为:华山松（55.51）>华北落叶松（53.60）>白桦（51.13）>山杨（50.30）>红桦（49.92）。乔木的器官含碳率为:叶（53.89）>干≈枝（52.6）>皮（52.1）>根（50.69）。灌木全株平均含碳率为47.81%,不同种的含碳率（%）依次为忍冬（48.30）>峨嵋蔷薇≈野李子（48.2）>荀子（46.65）,各器官含碳率（%）依次为:枝干（50.34）>根≈叶（47.1）。草本植物含碳率（%）平均为36.92,其中地上茎叶含碳率（44.22）高于根系（29.63）。3.典型植被类型的碳储量森林的植被碳密度（t/hm²）平均为37.65,其中乔木层、灌木层和草本层分别为33.42、3.97和0.26。各种林分依次为:华山松林（56.69）>山杨林（43.43）>桦木林（42.99）>华北落叶松人工林（30.37）>稀疏次生林（22.67）,均大于灌木林（10.16）。乔木层碳储量占总量的比例（%）依次为华山松林（98.85）>华北落叶松人工林（92.40）>桦木林（89.36）>山杨林（87.61）>稀疏次生林（65.44）。4.典型植被类型的土壤碳储量几种植被类型的枯落物平均含碳率（%）为38.15,其中未分解层、半分解层和已分解层分别为:44.87、35.69和30.07。不同植被类型枯落物平均碳密度（t/hm-2）为4.94,各类型依次为:华北落叶松人工林（6.53）>华山松林（5.35）>桦木林（4.29）>山杨林（3.17）>稀疏次生林（2.59）>灌木林（1.03）>草甸（0.28）>草地（0.17）。0-45cm的矿质土壤有机碳含量（%）为2.32-7.32,平均为4.42。矿质土壤有机碳含量及其样地间波动均随土壤加深而减小;矿质土壤有机碳密度（t/hm²）在94.10-335.09,平均为186.91;各植被类型土壤碳密度依次为华北落叶松人工林（197.66）>天然次生林（191.74）>亚高山草甸（163.11）>草地（160.74）>灌木林（140.06）。5.土壤碳库对造林时间和干扰程度的响应不论任何坡向,土壤有机碳含量在造林后均先下降后上升,对造林干扰的敏感程度随土层加深而减弱。土壤有机碳密度（t/hm²）在阳坡半阳坡为幼龄林（96.33）<灌丛（122.12）<中龄林（189.27）,即土壤有机碳库在造林20年时和灌丛对照相比已得到恢复;在阴坡半阴坡为幼龄林（192.37）<中龄林（222.03）<次生林（256.64）,即造林20年后土壤碳库与次生林对照相比仍未恢复。阴坡土壤碳库在任何林龄阶段都高于阳坡,说明阴坡森林土壤碳储存能力更大。对不同林龄样地土壤碳含量的统计分析表明,相对阳坡灌丛的土壤碳含量（32.13 g/kg）,阳坡半阳坡林地的土壤有机碳含量在造林后第8年时降至最低,降幅为3.72 g/kg,恢复需16年。相对阴坡次生林土壤碳含量（66.30g/kg）,造林后第16年土壤有机碳含量降至最低,降幅为22.77 g/kg,恢复需32年。在造林10年后,0-45cm土层的有机碳含量（g/kg）为灌丛（35.55）>灌丛稀植造林地（31.05）>常规密度及全面整地造林地（23.17）,说明减少造林整地干扰利于维持森林土壤的碳库功能。6.主要树种优势木年际生长固碳特征林木单株年固碳量和累积固碳量与树龄均有很好的二次函数关系,确定系数均在0.99以上。基于树木年轮分析得到的各树种10-20龄间的优势木单株年固碳量（kg/a）依次为:华北落叶松（4.06）>红桦（2.03）>华山松（1.80）>糙皮桦（1.52）>山杨（0.82）>白桦（0.65）>少脉椴（0.35）。基于树干径向变化记录仪测定得到的林分标准木的单株年固碳量（kg/a）平均值依次为白桦（3.74）>华北落叶松（3.28）>华山松（1.93）>红桦（0.86）。基于标准木计算的华北落叶松人工林和华山松-桦木次生林年固碳量分别为2.1和1.05 t/hm²,且分别有75%和73.7%是在6-7月份积累的。7.森林耗水量及固碳水分利用效率林分标准木的单株生长季（5-9月）总耗水量（kg）对华北落叶松人工林为972.9,次生林中的白桦和华山松为2272.9和1860.4。折合的生长季耗水深度对华北落叶松人工林为426.4 mm,华山松-桦木天然次生林为343.0mm,分别是降水量的97%和78%。林分标准木的单株水分固碳利用效率（tC/万tH₂O）为:华北落叶松（47）>白桦（16）>华山松（11）。华北落叶松人工林与次生林的植被固碳增长水分利用效率分别为4.9和3.0 （tC/万tH₂O）;维持生态系统碳库的水分利用效率分别为947和1851（tC/万tH₂O）。两种林分的固碳增长耗水成本分别为2030.3和40607 tH₂O/tC;碳维持耗水成本分别为10.6和5.4 tH₂O/tC。人工林的碳库功能维持的耗水成本是次生林的1.95倍。8.结论总体来看,落叶松人工林虽有较好的生产力和生长固碳功能,但其碳库维持的耗水成本接近次生林的2倍,且耗水量接近同期降水量会导致流域产流能力下降。同时,人工造林整地和抚育会造成土壤碳库储量大幅下降,且恢复周期长,需20-30年才能达到造林前的土壤碳库水平。基于本文阶段研究成果可以认为,要尽量减少对现有森林的过度干扰,不要进行皆伐后造林和大面积整地造林,而是要合理利用林木天然更新实现森林的持久覆盖和面积增长,要合理限制耗水较多的华北落叶松人工林,采用近自然经营的途径将其逐渐转化为乡土树种组成的森林,从而既能维持和提高森林固碳功能,又能保证流域的产水功能。更多还原

【Abstract】 In order to evaluate the carbon sequestration function of vegetation accurately, on the base of quantitate understand of the relationship of vegetation growth and carbon sequestration with its water consumption. and to provide the theoretic basis and the technical support for accurate assessment and prediction carbon storage of Liupan mountains and similar area, and to guide the vegetation recovery and management, Base on the survey of vegetation and soil and tree ring analysis, and measure of tree transpiration and radial growth based on the sap flow and dendrometer, the studeies were carried out in 2009 growth season in small watershed of Xiangshuihe, Liupan Mountains of Ningxia.1.Biomass of typical vegetation typesThe regression relationships between each organ biomass with DBH and H of Larix principis-rupprechtii and Betula spp. were established. The relationships of shrub organ biomass and basal diameter were builded.The order of mean biomass of each vegetaiton type is as Pinus armandii forest （102.70）> Betula forest （84.42）> Populus davidiana forest （79.97）> Larix principis-rupprechtii plantation （58.37）>open forest（44.91）. The biomass proportion of tree and shrub and herb layer is 90.04, 8.09 and 0.87%. The order of organ biomass ratio （%） of tree layer is as thunk（54.06）>branch（21.04）>root（16.92）>bark（5.34）>leaf（2.65）, and for the shrub layer, it is followed branch and thrunk （62.68）>root（30.55）>leaf （6.77）, and is above-groud （58.82）>root （41.18）.Average litter biomass of varios forest is 12.56 t/hm².Its order is as Larix principis-rupprechtii plantation （18.21）> Pinus armandii forest（102.70）> Betula forest （10.90）>. Populus davidiana forest （7.67）>open forest （7.06）, and higher than litter biomass of shrub （3.13）,meadows （0.82） and grass land（0.49）.2. Vegetation carbon content The whole plant mean carbon content is 52.22%. The order of carbon content of each tree species is as Pinus armandii （55.51%） > Larix principis-rupprechtii （53.60%） > Betula platyphlla （51.13%） > Populus davidiana （50.30%） > Betula albosinensis （49.92%）. The carbon content of tree organ is leaf （53.89%） > trunk≈branch （52.6%） > bark（52.1%） > root （50.7%）, the root is minimum （50.7%）. The shrub whole plant carbon content is 47.81%. The order of carbon content of each shrub species is as L.rupicola var.（48.30%） > Rosa meiensis （48.24%） > Prunus salicina （48.23%） > Cotongaster acutifolius （46.65%）. Different organ carbon content （%） decreased in the order of trunk andbranch （50.34）>root≈leaf （47.1）. The average carbon content of herbaceous plant is 36.92%, which of stem and leaf （44.22%） is higher than which of root （29.63%）.3. Vegetation carbon content and carbon sequestration of typical forest vegetation standThe average vegetation carbon density is 37.65 t/hm². which is 33.42 and 3.97 and 0.26 t/hm² of tree and shrub and herb layers. The order of carbon density of each vegetation type is Pinus armandii forest （56.69） > Populus davidiana forest （43.43） > Betula forest （42.99） > Larix principis-rupprechtii plantation 30.37) > open forest （22.67）, all of which is larger than its of shrub land （10.16）. The order of the carbon storage proportion of tree layer is Pinus armandii （98.85%） > Larix principis-rupprechtii plantation （92.40%）> Betula spp. forestation （89.36） > Populus davidiana （87.61%） > sparse secondary forest （65.44%）.4. The soil organic carbon storage of typical vegetation typesThe average litter carbon content of different vegetation types was 38.15%. which of undecomposed and half-decomposed and decomposed were 44.87 and 35.69 and 30.07% respectivly. The average litter carbon density of different vegetation types decreased in the order of Larix principis-rupprechtii plantation（4.06） > Pinus armandii （2.03） > > Betula utilis （1.52）> Populus davidiana （0.82）>Betula platyphlla （0.65） > Tilia paucicostata （0.35）.5. The respond of soil carbon pool for plant year and disturb degreeIn every slope aspect, the SOC presented a trend of firstly decreasing after tree-planting and then recovering with tree age; The sensitivity of SOC response to the tree-panting disturbance declined with increasing soil depth. The difference of stand condition and recoved years of soil organic desity recover to the level of before afforestation indicated that: young plantation （96.33） in sunny and semi-sunny slope < shrub land （122.12） < middle-aged plantation （189.27）; for the shady and semi-shady slopes, the order of SOC density is as young plantation （192.37） < middle-aged plantation （222.03） < secondary forestation （256.64）, showing that the SOC have been recovered after forestation for 20 years. The soil carbon orgnic carbon density of shady slope is higher than which in sunny slope at all stand age, suggested that the forest soil carbon pool of shady slope has strong ability for carbon sequestration than sunny slope.Based on the statistical analysis of the investigated data, the SOC content will decrease to its lowest point after 8 years forestation on the sunny/semi-sunny slopes, with a decrease of 3.72 g/kg compared to the control of shrub land （32.13g/kg） on sunny slope, and the fully recovering of SOC to the pre-forestation level will appear after 16 years of forestation. On the shady/semi-shady slopes, the SOC content will decrease to its lowest point after 16 years forestation, with a decrease of 22.77 g/kg compared to the control of secondary forests （66.30g/kg）, and the fully recovering of SOC to the pre-forestation level will appear after 32 years forestation.The absolute values of SOC pool on the shady slopes were always higher than that on the sunny slopes at any forest age, suggesting that the capacity of carbon sequestration of shady slopes is bigger than that of sunny slopes. 5)The types of planting disturbance can affect the variation of SOC pool. The mean SOC content of the 0-45 cm soil layer on sunny/semi-sunny slope was 31.05 g/kg after 10 years plantation if the trees were planted with sparse spacing, still lower than that of the control of shrub land （35.55 g/kg）, but higher than that if planted with the normal density （23.17g/kg）. This indicated that looking for the rational techniques in tree planting and forest management is an effective approach to reduce the SOC loss for young or middle-aged plantation to enhance their carbon sequestration function. In summary, the influence of plantation age, site condition and tree-planting disturbance on SOC should be considered for a more precise evaluation and prediction of the carbon sequestration of plantation.6. The characteristics of growth and carbon sequestration of dominent tree of main tree species All of annual carbon sequestration increment and cumulative carbon sequestration have quadratic correlation, with r2 higher than 0.99. The order of annual carbon sequestration between 10-20 tree age is as Larix principis-rupprechtii （4.06） > Pinus armandii forest （5.35） > Betula utili. （4.29） > Populus davidiana （3.17） > spares secondary forest （2.59）> shrubbery （1.03）> meadow （0.28）> grass land （0.17）. And 75% and 73.7% of that were accumulated in June to July.Mean annual carbon sequestration of single tree decreased in the order of Betula platyphlla （3.74）>Larix principis-rupprechtii （3.28） > Pinus armandii （1.80） > Betula albosinensis （0.86）. the annual carbon sequestration increment of stand woods of Larix principis-rupprechtii plantation and Pinus armandii-Betula forestation were 2.1 and 1.05 t/hm² respectivly, andThe average of vegetation carbon storage of several forest types is 37.65t/hm², in order Pinus armandii forest （56.69） > Populus davidiana forest （43.43） > Betula forest （42.99） > Larix principis-rupprechtii plantation 30.37) > open forest （22.67）, all of which is larger than shrub land （10.16） The carbon content of mineral soil is 2.32-7.32%. the average is 4.42%. The mineral soil carbon content and its fluctuation between different stand is decreased with increase of soil depth. Mineral soil organic carbon density is 94.10-335.09 t/hm². The average is 186.91. The order of soil carbon density of different vegetation types is as Larix principis-rupprechtii plantation （197.66）>natural forest (191.74t > meadow （163.11）>grass land （160.74）>shrubbery （140.06）.7.Forest water consumption and water use efficeient on carbon sequestrationTotal water consumption in growth season of Larix principis-rupprechtii stand wood is 972.9kg.The transpiration of stand wood of secondary forestation were 2272.9 kg of Betula albosinensis2279.and 1860.4 kg of Pinus armandii. The total water consumption of growth season of Larix principis-rupprechtii plantation was 426.4mm, and 343.0 mm of Pinus armandii-Betula spp. secondary forestation. those were 97% and 78% of precipitation respectively.The order of water use efficiency （t C/ 104 t H₂O） for carbon sequestration of single plant was Larix principis-rupprechtii （47） > Betula platyphlla （16） > Pinus armandii （11）. The water use efficiency on carbon sequestration of plantation and secondary forest were 4.9 and 3.0 （t C/ 104 t H₂O）. The water use efficiency for holding of carbon pool of ecologysystem were 947 and 1851 （t C/ 104 t H₂O）. corresponding water consumption cost of carbon storage increment were 10.6 and 5.4 t H₂O/ t C. which of plantation is 1.95 times to that of secondary forestation. 8. ConclusionOverall, biomass, vegetation carbon reserves of Larix principis-rupprechtii plantation was higher than secondary forestation, and has good productivity and growth of carbon sequestration functions. With water-consumption approached preciptation, wter consumption of plantation would lead to the decrease of water-yield of watershed. Artificial afforestation measure would lead to the decrease of soil carbon storage. and restore cycle is long, which need 20-30 years to reach the level of soil carbon stock before afforestation. Most importantly, the cost of water consumption of plantations carbon sequestration of soil and vegetation is as much as 1.95 times to secondary forest. When the whole basin from while simultaneously maintaining solid carbon function andwater production function to consider the stage, based on this research results, can think, want to reduce excessive interference of existing forests, do not carry all after thinning afforestation, don’t, but large soil preparation afforestation trees natural regeneration ability reasonable utilization of realizing forest area maintenance and growth, be reasonable limit consumption more Larix principis-rupprechtii plantation were, the near natural operation way gradually transformed into the forest of local growth, can not only maintain and enhance the watershed forest fixing carbon and function, and can guarantee the watershed water production function.更多还原