J Plant Ecol ›› 2021, Vol. 14 ›› Issue (4): 692-701.DOI: 10.1093/jpe/rtab023

• Research Articles • Previous Articles     Next Articles

Changes in carbon, nitrogen and phosphorus stoichiometry in decaying logs with gap positions in a subalpine forest

Qin Wang1,2, Wanqin Yang2, *, Han Li1, Zhuang Wang1, Chenhui Chang1,2,3, Rui Cao1 and Bo Tan1, *   

  1. 1 Long-term Research Station of Alpine Forest Ecosystems, Department of Ecology and Forestry, Institute of Forestry, Sichuan Agricultural University, Chengdu 611130, China, 2 Department of Soil Ecology and Remediation, School of Life Science, Taizhou University, Taizhou 318000, Zhejiang, China, 3 Systems Ecology, Department of Ecological Science, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands

    *Corresponding author. E-mail: scyangwq@163.com (W.Y.); bobotan1984@163.com (B.T.)
  • Received:2020-07-22 Revised:2020-09-27 Accepted:2021-02-10 Online:2021-03-09 Published:2021-08-01

Abstract:

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.

Key words: forest gap, decaying log, carbon, nutrients, subalpine forest, Abies faxoniana

摘要:
亚高山森林倒木碳氮磷化学计量特征随林窗位置的变化
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。

关键词: 森林林窗, 倒木, 碳, 养分, 亚高山森林, 岷江冷杉(Abies faxoniana)