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.