长江上游高山森林林窗对凋落物分解过程中可溶性碳的影响  

EFFECTS OF FOREST GAPS ON SOLUBLE CARBON DURING FOLIAR LITTER DECOMPOSITION IN AN ALPINE FOREST IN THE UPPER YANGTZE RIVER

作　　者：徐李亚 杨万勤[1] 李晗[1] 倪祥银[1] 何洁[1] 吴福忠[1] 

机构地区：[1]四川农业大学生态林业研究所林业生态工程重点实验室,高山森林生态系统定位研究站,四川温江611130

出　　处：《长江流域资源与环境》2015年第5期882-891,共10页Resources and Environment in the Yangtze Basin

基　　金：国家自然科学基金项目(31270498;31170423);国家"十二五"科技支撑计划(2011BAC09B05);四川省杰出青年学术与技术带头人培育项目(2012JQ0008;2012JQ0059);中国博士后科学基金特别资助项目(2012T50782)

摘　　要：采用凋落物分解袋法,以川西高山森林典型乔木(四川红杉Larix mastersiana、岷江冷杉Abies faxoniana、红桦Betula albo-sinensis和方枝柏Sabina saltuaria)和灌木(高山杜鹃Rhododendron lapponicum和康定柳Salix paraplesia)凋落物为研究对象,研究了林窗中心到郁闭林下不同生境(林窗中心、林冠林窗、扩展林窗和郁闭林下)中凋落物第一年分解不同关键时期(雪被形成期、雪被覆盖期、雪被融化期和生长季节)可溶性碳的动态特征。结果表明:6种凋落物可溶性碳和可溶性有机碳在冬季含量增加而在生长季节含量降低,而可溶性无机碳含量在全年呈降低趋势;雪被形成期,6种凋落物可溶性碳和可溶性有机碳在郁闭林下达到最大值,而雪被覆盖期在林窗中心和林冠林窗达到最大值,生长季节6种凋落物可溶性碳含量均低于初始含量。这表明全球气候变暖情景下,冬季林内雪被覆盖时间和厚度降低且生长季节延长将减少凋落物可溶性碳含量,且变化程度受到凋落物质量控制。Soluble carbon during foliar litter decomposition in alpine forests plays an important role in carbon cycling in ecosystems,which is also closely related to the material and energy flow in downstream ecosystems.However,forest gaps could regulate soluble carbon dynamics during litter decomposition by changing the frequency of soil freeze-thaw cycles in winter and hydrothermal environment in growing seasons,but little information has been available.Therefore,a field litterbag experiment was conduct in an alpine forest in western Sichuan Province,China from 15 November 2012to 31 October 2013.Foliar litter of typical arbor species（birch：Betula albo-sinensis,cypress：Sabina saltuaria,larch：Larix mastersiana and fir：Abies faxoniana）and shrub species（willow：Salix paraplesia,azalea：Rhododendron lapponicum）were selected.Samples of air-dried foliar litter were filled in nylon litterbags and placed on the forest floor with 2cm spacing between litterbags from the gap center,canopy gap edge,extended gap edge to closed canopy in the alpine forest.The litterbags were sampled at snow formation stage,snow cover stage,snow melt stage and growing season in the first year of decomposition.The results indicated that the content of soluble carbon and soluble organic carbon from the foliar litter of the six species showed a similar dynamical tendency at the first year of litter decomposition.Both contents of soluble carbon and soluble organic carbon increased in winter,and decreased in growing season,though the content of soluble inorganic carbon decreased in the first year of litter decomposition.The maximum contents of soluble carbon and soluble organic carbon in closed canopy were observed at snow formation stage regardless of litter species,but those in gap center and extended gap edge were observed at snow cover stage.In contrast,the contents of soluble carbon,soluble organic carbon and soluble inorganic carbon decreased significantly in growing season,even less than the initial contents.Multivariate analysis di

关 键 词：林窗 高山森林 可溶性碳 凋落物分解 雪被覆盖 

分 类 号：S718.53[农业科学—林学]