Dynamics of Understory Shrub Biomass in Six Young Plantations of Southern Subtropical China

Yuanqi Chen,Yanju Zhang,Xingquan Rao,Xi’An Cai,Shenglei Fu

doi:10.3390/f8110419

Abstract

Understory shrubs are an important component of forest ecosystems and drive ecosystem processes, such as ecosystem carbon cycling. However, shrub biomass carbon stocks have rarely been reported, which limits our understanding of ecosystem C stock and cycling. In this study, we evaluated carbon accumulation of shrub species using allometric equations based on height and basal diameter in six subtropical plantations at the age of 1, 3, 4 and 6 years. The results showed that plantation type did not significantly affect the total biomass of shrubs, but it significantly affected the biomass of Rhodomyrtus tomentosa, Ilex asprella, Clerodendrum fortunatum and Baeckea frutescens. The biomass of dominant shrub species R. tomentosa, I. asprella, Gardenia jasminoides and Melastoma candidum increased with stand age, while the biomass of C. fortunatum and B. frutescens decreased. The inconsistent biomass-time patterns of different shrub species may be the primary reason for the altered total shrub biomass in each plantation. Consequently, we proposed that R. tomentosa, I. asprella, G. jasminoides and M. candidum could be preferable for understory carbon accumulation and should be maintained or planted because of their important functions in carbon accumulation and high economic values in the young plantations of southern subtropical China.

Highlights

Shrubs are a type of vegetal group with a specific structure [1] and are essential to the biophysical and biodynamic processes of different ecosystems [2,3]
Our research provides useful references on management of understory shrub species based on carbon accumulation of the shrub biomass
The biomass of R. tomentosa, I. asprella, M. candidum increased with stand age

Summary

Introduction

Shrubs are a type of vegetal group with a specific structure [1] and are essential to the biophysical and biodynamic processes of different ecosystems [2,3]. In arid and semi-arid ecosystems, shrubs are conducive to the increase in the number of herb-layer plant species [4]. In subtropical forests, shrubs facilitate the growth of understory tree seedling [5,6]. Shrubs act as ecosystem engineers [7]. Understory shrub increases litter decomposition and the accumulation of litter-derived carbon (C) and nitrogen (N) in forest soils by altering soil microbial activity and community composition [8,9,10]. Physiological and ecological characteristics of shrubs have been systematically studied [11,12,13]

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Conclusion