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Scientia Silvae Sinicae ›› 2020, Vol. 56 ›› Issue (5): 1-11.doi: 10.11707/j.1001-7488.20200501

Special Issue: 森林生态 森林培育与经营

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Biomass Estimation Coefficient and Its Impacting Factors for Eucalyptus Plantation in China

Wankuan Zhu,Yuxing Xu,Zhichao Wang,Apeng Du*   

  1. China Eucalypt Research Centre Guangdong Zhanjiang Eucalyptus Plantation Ecosystem Research Station Zhanjiang 524022
  • Received:2018-08-30 Online:2020-05-25 Published:2020-06-09
  • Contact: Apeng Du

Abstract:

Objective: The relationship between the three biomass estimation coefficients and the stand structure, climatic factors, and topographic factors was analyzed, and the main influencing factors of biomass estimation coefficients were determined to provide a scientific basis for accurately estimating the biomass of Eucalyptus plantations at regional scale. Method: By collecting and collating historical data from published literature on biomass measurements of Eucalyptus plantations, we analyzed and explored the relationship between three common biomass estimation coefficients (biomass conversion and expansion factor BCEF, biomass expansion factor BEF, and root/shoot ratio R) and stand structure (stand age, mean DBH, mean tree height, stand density, and standing volume), climatic factors (annual average temperature and annual average precipitation), and topographic factor (elevation). Result: Means of BCEF, BEF, and R were 0.658 Mg·m-3 (n=119, SD=0.150), 1.251 (n=176, SD=0.167), and 0.190 (n=144, SD=0.102), respectively. The corresponding range values were 0.46-0.76 Mg·m-3, 1.05-1.35, and 0.04-0.36, respectively. BCEF value displayed a decrease followed by an increase with the increase of mean DBH. BCEF value gradually decreased with the increase of mean tree height (r2=0.366), stand density (r2=0.430), and standing volume (r2=0.405). BEF value decreased and became stable with the increase of stand age(r2=0.765), mean tree height(r2=0.734), and standing volume(r2=0.578), decreased first and then increased with the increase of mean DBH(r2=0.644). R value decreased gradually and then became stable with the increase of stand age(r2=0.665), mean tree height(r2=0.338), stand density(r2=0.275), and standing volume(r2=0.403).BCEF value showed a decrease first followed by an increase with the increases of temperature (r2=0.193) and precipitation (r2=0.200). Values of BEF and R did not show a significant functional relationship with changes in temperature and precipitation. Three biomass estimation coefficients showed a trend of increase with elevation, and the equation fitting accuracies were 0.455, 0.501, and 0.314. Conclusion: The goodness of fit between stand density and BCEF was relatively high, and so did the stand age and the BEF and R. Stand density and age were the main factors affecting the estimation coefficient of biomass. The influence of topographic factors on the three biomass estimation coefficients was next only to the stand density and the age. The climatic factor only had some effects on the BCEF. Therefore, the difference in biomass estimation coefficients caused by stand structure and topographic factors should be considered when estimating the biomass of Eucalyptus plantations at regional scale.

Key words: Eucalyptus plantations, biomass conversion and expansion factor, biomass expansion factor, root/shoot ratio, stand structure, elevation

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