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缙云山常绿阔叶林凋落物量及动态特征

Litterfall amount and dynamic characteristics of evergreen broad-leaved forest in Jinyun Mountain

  • 摘要: 亚热带常绿阔叶林是中国森林的重要组成部分。从群落尺度探讨凋落物量、组成、动态及其气候影响因素, 对了解森林生态系统的物质循环过程和群落构建机制等方面具有重要意义。基于缙云山常绿阔叶林永久样地2014—2021年的凋落物监测数据, 分析该研究地凋落物量及其各组分之间的动态和组成特征, 同时探讨温度和降水2类气候因子对凋落物量的影响。结果表明: 1)缙云山亚热带常绿阔叶林年平均凋落物量为6.25 t/hm2, 年际差异不显著(P>0.05);2)在凋落物组成上以叶片为主(占凋落物总量的72.50%); 3)不同组分凋落物的凋落节律存在明显差异, 其中叶片和繁殖体的凋落节律也与凋落物总量保持一致, 均为双峰型, 发生在4、5和11月, 而枝条与其他残渣凋落物的凋落节律不明显; 4)月平均气温、最湿月降水量和最干月降水量是影响凋落物量的主要气候因素, 且月平均气温的影响更显著。其中月平均气温对凋落物总量、叶凋落物量、其他植物残渣影响显著, 而繁殖体凋落物量主要受月平均气温、最湿月降水量和最干月降水量的影响。

     

    Abstract:
    Background Subtropical evergreen broad-leaved forest is an important part of forests in China. This study takes the evergreen broad-leaved forest in Jinyun Mountain as the research object, and analyzes the litterfall yield, composition, dynamics and litterfall rhythm of the evergreen broad-leaved forest in the study area from 2014 to 2021 at the community scale, and discusses the response of litterfall yield to climatic factors, aiming to understand the material and energy cycle of forests.
    Methods Authors established a permanent monitoring plot of 1.00 hm2 evergreen broad-leaved forest in Jinyun Mountain in October 2013, and collected all litterfall in the collection basket at the end of each month. After being brought back to the laboratory for finishing, it was dried to a constant mass amount in an oven at 80 ℃. The litterfall was divided into four categories of leaves, branches, reproduction and other. The leaves were identified to species, and each composttion was weighed with an electronic balance with an accuracy of 0.01 g.
    Results 1) The mean annual total litterfall of subtropical evergreen broad-leaved forest in Jinyun Mountain was 6.25 t/hm2, and the interannual difference was not significant (P>0.05). 2) The composition of litterfall was dominated by leaves (accounting for 72.50% of the total litterfall). 3) The litterfall rhythms of different components were significantly different. The litterfall rhythms of leaves and reproduction were also consistent with that of the total litterfall, which were bimodal and occurred in April, May and November, while the litterfall rhythms of branches and other were not obvious. 4) Mean monthly temperature, precipitation of the wettest month and precipitation of the driest month were the main climatic factors affecting litterfall production, and the effect of mean monthly temperature was more significant. The mean monthly temperature had a significant effect on the total litterfall, leaves and other litterfall, while the reproduction was mainly affected by the mean monthly temperature, precipitation of the wettest month and precipitation of the driest month.
    Conclusions 1) Affected by climate, forest structure and other factors, the total amount of litterfall and its composition showed significant differences. 2) The species composition of plant communities is the main factor affecting litterfall dynamics in Jinyun Mountain, and its litterfall characteristics are significantly affected by evergreen and deciduous tree species. 3) The total amount of litterfall in Jinyun Mountain is more related to temperature factors than precipitation factors. The reason is that Jinyun Mountain is located in the subtropical zone, with high air humidity and abundant precipitation, which can meet the water demand of plant growth and development. Temperature is a key factor limiting forest productivity and litterfall amount.

     

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