Aboveground Biomass Allometric Models for Evergreen Broad-Leaved Forest Damaged by a Serious Ice Storm in Southern China

Abstract

A catastrophic ice storm occurred in the spring of 2008, which severely destroyed nearly 13% of China’s forests; among them, the broad-leaved forest suffered the most extensive damage. In this study, allometric models of the evergreen broad-leaved forests damaged at different recovery stages after the disaster were established to estimate the aboveground biomass of damaged trees. Plant plots were established and surveyed in damaged forests to determine species composition and diameter distribution, and finally a sample scheme was formulated that contained 47 trees from 13 species. The destructive measurements of aboveground biomass of trees selected according to the scheme were conducted in 2008, 2010, 2012 and 2016, respectively. Undamaged trees in the same region were also selected to measure the biomass in 2010. Linear regression of logarithmic transformation of the power function form was performed using Diameter at Breast Height (DBH) as predictor to develop biomass allometric models. The results showed that the ice storm caused tree aboveground biomass loss, which caused different parameters of the tree biomass models at different recovery stages. The models have a high accuracy in predicting trunk and total aboveground biomass, with high determination coefficients (R2, 0.913~0.984, mean 0.957), and have a relatively low accuracy in predicting the biomass of branches and leaves (R2, 0.703~0.892, mean 0.784). The aboveground biomass reduced by 35.0% on average due to the ice storm, and recovered to the same level of undamaged trees in the same diameter 8 years after the disturbance. The branches and leaves recovered very fast, and the biomass of these parts exceeded that of the undamaged trees, reaching the same diameter 2 years after the disaster, indicating an over compensatory growth. The trees with a smaller diameter were mostly composed of middle and late succession species, and recovered faster than other species, indicating that the ice storm may alter the forest structure and accelerate community succession. The biomass allometric models built in this study, combined with forest inventory data, can estimate forest biomass loss and recovery after disturbance, and offer an important sense of the assessment of forest damage and the formulation of forest post-disaster management strategies.

Allometric relationships, functional differentiations, and scaling of growth rates across 151 tree species in China

“…Thus, the lower H max and increased growth elasticity in China could be related to the combined climatic and soil properties, management histories, compositional species pool or past disturbances (Zhao et al 2009, 2013, Zhang et al 2014, Ni et al 2015, Cai et al 2020, Mao et al 2020), as already reported between wet and moist forests in global‐scale studies (Tao et al 2016, Zhang et al 2016). Similar trends were reported between frequently disturbed and undisturbed primary forests at local and regional scales (Thomas et al 2015, Tong et al 2020, Zhao et al 2020), suggesting a combined environmental and disturbing controls of tree allometry.…”

“…In contrast, evergreen forests should dominate realistic ecological conditions and outperform deciduous forests in wet, warm, and light‐limited environments (Givnish 1988, 2002, Way and Oren 2010). The evergreen trees dominating central southern subtropical forests and eastern and middle‐low‐elevation conifer continental forests of China seemingly confirm this hypothesis, and the predefined patterns differ from those of other forests worldwide (Ge and Xie 2017, Zhao et al 2020). However, few studies have reported wide comparisons across levels of continental forests and tree species at functional biogeographical scales.…”

“…Here, we selected eight sites with long‐term observational data from CERN to cover the typical forest types with various ages in this region. The chosen sites conformed to the following criteria (Table 1): (1) located in the eastern China monsoon region (latitude 21°54'–42°24′ N, longitude 101°12′–128°30′ E) covering the typical climate zones from south to north (tropical, subtropical, warm temperate, and temperate) and humid to subhumid areas from southeast and northwest (Ge et al 2019); (2) old‐growth forest stands (age ≥200 yr) span all tropical, subtropical, and temperate climate zones and free from large‐scale natural (e.g., major cyclone disturbance, wind, or fire) or anthropogenic disturbances (e.g., industrial logging), whereas middle‐aged forests (30–60 yr old stands) span subtropics and warm temperate climate zones and experience frequent disturbances (e.g., managing logging or extreme climate events, such as ice storms) (Tong et al 2020, Zhao et al 2020); (3) 40–2,450 m above sea level; (4) approximately mean annual precipitation of 650–1,931 mm and mean annual temperature of 4.8–21.7°C; (5) diverse forest ecosystems ranging from evergreen broad‐leaved, broad‐leaved coniferous mixed, and coniferous forests to deciduous coniferous and deciduous broad‐leaved forests (Ge et al 2019).…”

“…In these environments, the taller height of deciduous trees at smaller diameters (as evidenced by a greater Gompertz parameter d H ) may help to offset the disadvantage of relatively short photosynthetic periods and decreased carbon fixation when co-occurring with more elastic successive evergreens (as evidenced by a more indistinguishable theoretical allometric slope parameter β). Furthermore, the differing allometric growth strategies in deciduous and evergreen species may influence their sensitivities to global warming (Way and Oren 2010) or vulnerabilities to disturbances (Zhao et al 2020). Based on data from 63 studies, a recent meta-analysis confirmed that the response of tree taper (the ratio of trunk diameter to stem height) was significantly higher in deciduous trees than in evergreen trees (Way and Oren 2010), of which a 10°C increase in growth temperature was expected to induce deciduous growth with a generally 3.4-fold increase in shoot height and a 1.5-fold increase in trunk diameter.…”

“…Furthermore, disturbance regimes and biogeographical and phylogenetic history jointly establish the local to regional pools of tree species from which standing forests can be composed; thus, they may be critical in driving large‐scale variance in tree size allometric relationships (Forrester et al 2017). Furthermore, disturbances due to extreme weather and climate events, such as ice storms, are common in China (Zhao et al 2020). Thus, the variation in size‐dependent allometric relationships, functional differentiations, and interspecific scaling of growth rates warrants further in‐depth exploration (King et al 2006 b , Wang et al 2006, Feldpausch et al 2011, Ledo et al 2016, Mao et al 2020) especially as it relates to competition, growth rate, disturbance regimes, phylogenetic history, and environmental conditions (Subedi et al 2019, Tong et al 2020).…”