Integrating regional climate change into allometric equations for estimating tree aboveground biomass of Masson pine in China

Abstract

Abstract& Key message A climate-sensitive aboveground biomass (AGB) equation, in combination with nonlinear mixedeffects modeling and dummy variable approach, was developed to examine how climate change may affect the allometric relationships between tree diameter and biomass. We showed that such changes in allometry need to be taken into account for estimating tree AGB in Masson pine. & Context As a native species and being widely distributed in subtropical China, Masson pine (Pinus massoniana Lamb.) forests play a pivotal role in maintaining forest ecosystem functions and mitigation of carbon concentration increase at the atmosphere. Traditional biomass allometric equations do not account for a potential effect of climate on the diameterbiomass relationships. The amplitude of such an effect remains poorly documented. & Aims We presented a novel method for detecting the longterm (2041-2080) effects of climate change on the diameterbiomass relationships and the potential consequences for long-term changes of biomass accumulation for Masson pine. & Methods Our approach was based on a climate-sensitive AGB model developed using a combined nonlinear mixedeffects model and dummy variable approach. Various climaterelated variables were evaluated for their contributions to model improvement. Heteroscedasticity was accounted for by three residual variance functions: exponential function, power function, and constant plus function. & Results The results showed that diameter at breast height, together with the long-term average of growing season temperature, total growing season precipitation, mean temperature of wettest quarter, and precipitation of wettest quarter, had significant effects on values of AGB. Excessive rain during the growing season and high mean temperature in the wettest quarter reduced the AGB, while a warm growing season and abundant precipitation in the wettest quarter increased the AGB.

Aboveground biomass estimation at different scales for subtropical forests in China

“…Muukkonen ( 2007 ) found that allometric equations with only DBH as an independent variable provided lower overall estimations of tree biomass. Models at different scales may lead to variation of biomass estimation because of difference of climatic conditions, site quality, and forest structures (Muukkonen 2007 ; Fu et al 2017 ). In this study, we found that model 1 and model 2 had better accuracies for AGB estimations than model 3 (Fig.…”

“…Regional climate data affected the precision of the regional model (Drake et al 2003 ; Dewalt and Chave 2004 ; Chave et al 2005 ; Wang 2006 ; Fu et al 2017 ). In this study, MAT and MAP were clearly distinct among eight ecoregions (Table 1 ).…”

“…The influences of climate were even more significant in EBF (Table 3 ). Therefore, forest regional climate data should be considered when the regional models were employed (Muukkonen 2007 ; Fu et al 2017 ).…”

“…Thus, many scientists gave efforts to improve the tree allometric models at single tree, plot, regional, national, or even worldwide scales, using easily measured dimensional variables, such as diameter at breast high ( DBH ) and tree height ( H ) (Brown et al 1989 ; Ter-Mikaelian and Korzukhin 1997 ; Chave et al 2005 ; Návar 2009 ; Genet et al 2011 ). However, different models may lead to greatly variation of biomass estimation because of difference in climatic conditions, site quality, and forest types (Muukkonen 2007 ; Fu et al 2017 ). Therefore, sampling at different scales and creating general biomass model were very important to reduce the uncertainty of applying different models (Chave et al 2014 ).…”

Forest stand biomass of Picea spp.: an additive model that may be related to climate and civilisational changes

“…Analysis of the results of such studies revealed significant contradictions and uncertainties about the assessment of these indices' dependence on temperature and precipitation using both empirical and functional models (Eggers et al, 2008;Shuman, Shugart, 2009;Poudel et al, 2011;Han et al, 2018). Contradictory results were obtained even within a single region, while the influence of the same climatic factors on the biological production of stands of certain tree species (genera) in the Trans-Eurasian climatic gradients of temperature and precipitation is still unknown, since the available information is fragmentary and contradictory (Strömgren, Linder, 2002;Wilmking et al, 2004;Stegen et al, 2011;Fu et al, 2017), and is obtained in narrow temperature and precipitation ranges shifted in magnitude in different ecoregions.…”