Assessing biotic and abiotic effects on forest productivity in three temperate forests

Abstract

It is well understood that biotic and abiotic variables influence forest productivity. However, in regard to temperate forests, the relative contributions of the aforementioned drivers to biomass demographic processes (i.e., the growth rates of the survivors and recruits) have not received a great deal of attention. Thus, this study focused on the identification of the relative influencing effects of biotic and abiotic variables in the demographic biomass processes of temperate forests. This study was conducted in the Changbai Mountain Nature Reserve, in northeastern China. Based on the observational data collected from three 5.2‐hectare forest plots, the annual above‐ground biomass (AGB) increment (productivity) of the surviving trees, recruits, and the total tree community (survivors + recruits) were estimated. Then, the changes in the forest productivity in response to biotic variables (including species diversity, structural diversity, and density variables) along with abiotic variables (including topographic and soil variables) were evaluated using linear mixed‐effect models. This study determined that the biotic variables regulated the variabilities in productivity. Density variables were the most critical drivers of the annual AGB increments of the surviving trees and total tree community. Structural diversity enhanced the annual AGB increments of the recruits, but diminished the annual AGB increments of the surviving trees and the total tree community. Species diversity and abiotic variables did not have impacts on the productivity in the examined forest plots. The results highlighted the important roles of forest density and structural diversity in the biomass demographic processes of temperate forests. The surviving and recruit trees were found to respond differently to the biotic variables, which suggested that the asymmetric competition had shaped the productivity dynamics in forests. Therefore, the findings emphasized the need to consider the demographic processes of forest productivity to better understand the functions of forests.

Multiple Drivers of Biomass Change in Subtropical Natural Forests

“…In addition, the relationship between species richness (or phylogenetic diversity) and biomass was not statistically signi cant when other factors were accounted for in the multiple regression model (Fig. 3a), indicating that species richness and phylogenetic diversity have independent effects on biomass, which is consistent with previous studies in temperate forests (Fotis et al 2017;Yue et al 2020). Linear regression analysis revealed that species richness and phylogenetic diversity are a better predictor of biomass that functional diversity.…”

“…Tree size inequality is caused by both differences with and among species and represents niche differentiation and facilitation (Coomes et al 2009; Morin et al 2011), a key process for maintaining species diversity and the positive diversity-productivity relationships. Together with previous studies, furthermore, we have demonstrated that the positive impact of stand density on forest biomass in natural forest ecosystems (van der Sande et al 2017; Yuan et al 2018;Yue et al 2020). Stand density can re ect the available resources and space occupation of trees and may also, to some extent, re ect intraspeci c interactions (Morin 2015;Fortunel et al 2018).…”

A classification of woody communities based on biological dissimilarity

“…Biological dissimilarities have been widely used in multiple areas of forest ecological research, such as examining community assembly mechanisms (Swenson & Enquist, 2009; Kraft & Ackerly, 2010; Spasojevic & Suding, 2012), exploring vegetation evolutionary processes (Bouchenak‐Khelladi et al, 2010; Byrne & Murphy, 2020), and assessing the relationship between biodiversity and ecosystem functioning (Tilman et al, 1997; Paquette & Messier, 2011; Finegan et al, 2015; Hao et al, 2018, 2020; Yue et al, 2020). Some previous studies have attempted to incorporate biological attributes into vegetation classifications.…”

“…This is especially relevant in global assessments, for example, when forest vegetation data are collected from large-scale forest inventories. Murphy, 2020), and assessing the relationship between biodiversity and ecosystem functioning (Tilman et al, 1997;Paquette & Messier, 2011;Finegan et al, 2015;Hao et al, 2018Hao et al, , 2020Yue et al, 2020). Some previous studies have attempted to incorporate biological attributes into vegetation classifications.…”

“…Such attributes have been widely used in forest ecological research, e.g. in examining community assembly mechanisms (Swenson & Enquist, 2009;Kraft & Ackerly, 2010;Spasojevic & Suding, 2012), quantifying forest diversity, and assessing the relationships between diversity and ecosystem functioning (Tilman et al, 1997;Paquette & Messier, 2011;Finegan et al, 2015;Hao et al, 2018Hao et al, , 2020Yue et al, 2020). Studies that integrate species compositional and biological heterogeneity may be considered more meaningful than those which consider only species diversity (Clarke & Warwick, 1998;Webb et al, 2002;Cadotte et al, 2013).…”