Effects of Stand Age on Biomass Allocation and Allometry of Quercus Acutissima in the Central Loess Plateau of China

Bin Yang,Jianyun Zhou,Wenyan Xue,Wenhui Zhang,Shichuan Yu

doi:10.3390/f10010041

Bin Yang, Jianyun Zhou + Show 3 more

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https://doi.org/10.3390/f10010041

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Journal: Forests	Publication Date: Jan 9, 2019
Citations: 20	License type: CC BY 4.0

Affiliation: North West Agriculture and Forestry University

Abstract

We studied the effects of stand age on allocation and equation fitting of aboveground and below-ground biomass in four Quercus acutissima stands (14, 31, 46, and 63 years old) in the Central Loess Plateau of China. The stem wood, stem bark, branch, foliage, and belowground biomass of each of the 20 destructive harvesting trees were quantified. The mean total biomass of each tree was 28.8, 106.8, 380.6, and 603.4 kg/tree in the 14-, 31-, 46-, and 63-year-old stands, respectively. Aboveground biomass accounted for 72.25%, 73.05%, 76.14%, and 80.37% of the total tree biomass in the 14-, 31-, 46-, and 63-year-old stands, respectively, and stem wood was the major component of tree biomass. The proportion of stem (with bark) biomass to total tree biomass increased with stand age while the proportions of branch, foliage, and belowground biomass to total tree biomass decreased with stand age. The ratio of belowground biomass to aboveground biomass decreased from 0.39 in the 14-year-old stand to 0.37, 0.31, and 0.24 in the 31-, 46-, and 63-year-old stands, respectively. Age-specific biomass equations in each stand were developed for stem wood, stem bark, aboveground, and total tree. The inclusion of tree height as a second variable improved the total tree biomass equation fitting for middle-aged (31-year-old and 46-year-old) stands but not young (14 years old) and mature (63 years old) stands. Moreover, biomass conversion and expansion factors (BCEFs) varied with stand age, showing a decreasing trend with increasing stand age. These results indicate that stand age alters the biomass allocation of Q. acutissima and results in age-specific allometric biomass equations and BCEFs. Therefore, to obtain accurate estimates of Q. acutissima forest biomass and carbon stocks, age-specific changes need to be considered.

Highlights

Oak forests play an important role in storing atmospheric CO2 in terrestrial ecosystems, both through accumulation of biomass and production of organic compounds with long C residence times, and, help mitigate global climate change [1,2]
Allometrics appears to be a useful tool for obtaining precise descriptions of biomass allocation patterns
Our study revealed the age dependence of biomass allocation and of the parameters of allometric equations

Summary

Introduction

Oak forests play an important role in storing atmospheric CO2 in terrestrial ecosystems, both through accumulation of biomass and production of organic compounds with long C residence times, and, help mitigate global climate change [1,2]. Understanding the development of tree biomass throughout the entire life cycle is required to accurately estimate the carbon stock at regional and national scales [4,5]. In 2003, in an effort to estimate forest biomass and carbon storage of the National Forest Inventory (NFI) system in participating countries, the Intergovernmental Panel on Climate Change (IPCC) proposed the use of the biomass conversion and expansion factors (BCEFS) and root-shoot ratio (RSR) for forests in different geographical regions [6]. As there can be high uncertainty in these parameters [7], it is crucial to develop indigenous models and parameters of tree biomass. Many papers on modeling individual tree biomass in

Results

Discussion

Conclusion