High Mortality and Low Net Change in Live Woody Biomass of Karst Evergreen and Deciduous Broad-Leaved Mixed Forest in Southwestern China

Libin Liu,Zhonghua Zhang,Qiaolian Zhong,Jian Ni,Gang Hu

doi:10.3390/f9050263

Abstract

Repeated observation based on large permanent monitoring plots is a key method for directly understanding forest regeneration dynamics. Karst forests grow slowly in adverse habitats and possess a special regeneration mode. However, no data can support these properties because no repeated observations have been performed. The mortality, recruitment, and net change in live woody biomass (NPPlw) of a karst evergreen and deciduous broad-leaved mixed forest in Central Guizhou Province, Southwestern China, were studied on the basis of a short-term continuous monitoring (3 years) of a 2 ha plot. The species richness of individuals with a diameter at breast height (DBH) ≥ 1 cm decreased from 66 to 58 during the study period. Eight species disappeared, and no new species appeared. The individual number declined from 16,821 to 15,003 because most species indicated more deaths than recruitments. Trees presented the lowest mortality rate, and shrubs presented the highest recruitment rate among the species. Individual death number decreased with the increase in DBH classes. The estimated aboveground NPPlw was 8.41 t ha−1 year−1. The survivors, recruitments, and deaths contributed 10.88, 0.11, and −2.58 t ha−1 year−1, respectively. Trees (8.37 t ha−1 year−1), rather than shrubs (0.04 t ha−1 year−1) and lianas (−0.004 t ha−1 year−1), were the major contributors. The karst forest presented higher mortality and lower NPPlw than nonkarst forests in subtropical China and in the world.

Highlights

Community dynamics such as mortality, recruitment, and net primary productivity (NPP)have been extensively studied in forest ecology [1]
Owing to establishing the protocol of global forest dynamics permanent plots [10], many large plots that consist of tropical mountain rain forest [18], subtropical evergreen broad-leaved forest [19,20,21,22,23], subtropical evergreen and deciduous broad-leaved mixed forest [24], temperate coniferous and broad-leaved mixed forests [25,26], temperate coniferous forest [27], and temperate deciduous broad-leaved forests [9,27] in China were established
Conducting short-termofcontinuous of unstudied but (e.g., important conducting short-term continuous monitoring unstudiedmonitoring but important forest types karst forest types is crucial, long-term continuous monitoring should be forest) is crucial, long-term continuous monitoring should be conducted in future studies

Summary

Introduction

Community dynamics such as mortality, recruitment, and net primary productivity (NPP)have been extensively studied in forest ecology [1]. Due to the long dynamic period of forests, multifarious indirect research methods, such as succession sequence, dendrochronology, pollen analysis, and vegetation modelling, have been used to explore forest dynamics indirectly [2,3,4]. These methods demonstrate disadvantages [5,6,7,8,9]. Conducting long-term and continuous observations of China’s forests to determine their regeneration and growth dynamics will contribute considerably to global biodiversity maintenance and carbon cycling [13,14,15,16,17]. Owing to establishing the protocol of global forest dynamics permanent plots [10], many large plots that consist of tropical mountain rain forest [18], subtropical evergreen broad-leaved forest [19,20,21,22,23], subtropical evergreen and deciduous broad-leaved mixed forest [24], temperate coniferous and broad-leaved mixed forests [25,26], temperate coniferous forest [27], and temperate deciduous broad-leaved forests [9,27] in China were established

Results

Discussion

Conclusion