Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests
Rahman M, Billah M, Rahman MO, Datta D, Ahsanuzzaman M, Islam M (2021)
Publication Type: Journal article
Publication year: 2021
Journal
Book Volume: 483
Article Number: 118908
DOI: 10.1016/j.foreco.2020.118908
Abstract
Tropical forests have been focused for mitigating climate change impact through carbon sequestration in plant biomass under clean development mechanism (CDM). Since trees represent more than 98% of the above ground plant biomass, variation in tree growth rate drives carbon dynamics in tropical forests. By using tree-ring analysis, trait-based measurements, and field observations, we aimed at understanding the drivers of growth rate variation in four South Asian tropical moist forest tree species varying in plant functional types. Principal component analysis (PCA) revealed that mainly demographic and wood traits represented the first axis explaining 37% of the variance, whereas the second axis was represented by the leaf traits. Stem growth rate (DI) showed a nonlinear negative relation with competition index (CI) and the ratio of crown surface area to basal area (CBR) in three out of four tree species (p < 0.001) except Lagerstroemia speciosa which showed no significant relationship with any of the studied variables. DI was linearly positively related with light interception index (LI) and the ratio of sapwood area to heartwood area (SHR) in the shade intolerant Magnolia champaca and Toona ciliata (p < 0.001). Sap wood area (SA) had a strong positive effect on DI in the three species (p < 0.001). Taking tree size as a random factor and thus accounting for ontogenetic effects on tree growth, linear mixed effect modelling revealed that CI, SA and SHR are the best predictors of DI in M. champaca (AIC = 25.81, R2m = 0.81) and T. ciliata (AIC = 62.95, R2m = 0.61). In C. tabularis, CI, SA and CBR included in the best model predicting DI (AIC = 94.62, R2m = 0.55). Variance partitioning analysis showed that the highest pure effect was observed in C. tabularis contributed by CI (12%), while the highest joint effect was found in M. champaca contributed by CI, SA and SHR (40%). Our analyses suggest that competition by neighbouring trees especially for soil moisture and the amount of active xylem portion are the main drivers of tree growth in moist tropical forests. Since tree growth rates regulate forest carbon dynamics, the insights into the growth drivers of the four selected species revealed by the study have important implications for forest/plantation management with a focus on carbon storage under CDM.
Authors with CRIS profile
Mizanur Rahman
Lehrstuhl für Geographie (Physische Geographie)
Mahmuda Islam
Lehrstuhl für Geographie (Physische Geographie)
Involved external institutions
Bangladesh (BD)How to cite
APA:
Rahman, M., Billah, M., Rahman, M.O., Datta, D., Ahsanuzzaman, M., & Islam, M. (2021). Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests. Forest Ecology and Management, 483. https://dx.doi.org/10.1016/j.foreco.2020.118908
MLA:
Rahman, Mizanur, et al. "Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests." Forest Ecology and Management 483 (2021).
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