亚高山森林倒木碳氮磷化学计量特征随林窗位置的变化

• 作 者: Qin Wang Wanqin Yang Han Li Zhuang Wang Chenhui Chang Rui Cao Bo Tan
• 机 构: Long-term Research Station of Alpine Forest Ecosystems,Department of Ecology and Forestry,Institute
• 出 处: 植物生态学报（英文版）
• 发表日期: 2021年4期
• 关键词: forest gap decaying log carbon nutrients subalpine forest Abies faxoniana

森林林窗对太阳辐射和降水(主要是降雨和降雪)的再分配可造成林窗内外微环境条件的异质性.本研究旨在通过改变微环境,测试林窗对倒木碳(C)、氮(N)和磷(P)化学计量比的影响.在青藏高原东部的亚高山森林中,将Ⅰ-Ⅴ腐解等级的岷江冷杉(Abies faxoniana)倒木分别置于林窗中心(GC)、林窗边缘(GE)和郁闭林下(CC)进行原位培养,分别于2013-2016年8月测定了腐烂树皮、边材和心材的C、N、P含量.研究结果表明,树皮N浓度从CC到GC呈下降趋势,而边材和心材则表现出相反的趋势.此外,边材和心材Ⅳ、Ⅴ腐解等级的C/N从CC到GC呈下降趋势,心材Ⅴ腐解等级的N/P从CC到GC呈增加趋势,这表明森林林窗对高度腐解等级倒木的C/N/P化学计量比有强烈影响.简而言之,高度腐烂的倒木更容易受到微环境的影响,必要时应适当调整郁闭林下或林窗中心的高度腐烂的倒木比例.“,”Aims The redistribution of forest gaps based on solar radiation and precipitation(mainly rainfall and snowfall)can create heterogenous microenvironments inside and outside the gaps.Here,we investigated the effects of forest gaps on carbon(C),nitrogen(N)and phosphorus(P)stoichiometry in decaying logs by altering the microenvironments.Methods Minjiang fir(Abies faxoniana)logs of decay classes Ⅰ-Ⅴ were incubated in situ on the floor under the gap center(GC),gap edge(GE)and closed canopy(CC)in a subalpine forest in the eastern Qinghai-Tibet Plateau.The C,N and P concentrations in decaying bark,sapwood and heartwood were measured in August from 2013 to 2016.Important Findings Our results showed that the N concentration in bark decreased from the CC to the GC,while the opposite trend was found in sapwood and heartwood.Additionally,the C/N ratio in sapwood and heartwood of decay classes Ⅳ and Ⅴ decreased from the CC to the GC,and the N/P ratio in heartwood of decay class Ⅴ increased from the CC to the GC,implying that forest gaps have strong effects on C/N/P stoichiometry in highly decayed logs.Briefly,highly decayed logs are more susceptible to the microenvironment,and the proportion of highly decayed logs under the CC or the GC should be appropriately adjusted if necessary.