Wood species identity alters dominant factors driving fine wood decomposition along a tree diversity gradient in subtropical plantation forests
2021
Wu, Donghao | Pietsch, Katherina A. | Staab, Michael | Yu, Mingjian
Microclimate and biotic factors drive wood decomposition. Yet, relatively few studies have been conducted in warmer tropical and subtropical forests compared with colder temperate and boreal forests, where climate might have stronger limitations on decomposition. Besides, conclusions on decomposition are generally based on single wood species or standardized materials. Thus, a general assessment if wood species identity alters dominant factors of decomposition in subtropical forest could improve the predictability of current C cycle models. We measured fine wood mass‐loss rates of seven widespread tree species in southeast China at two time steps (after 1 and 2 years) in subtropical plantation forests with tree species diversity manipulated. We found that termites exceeded fungi in consuming fine woody debris, and termite foraging intensity decreased with lignin content. Tree species diversity increased fungal hyphal coverage on fine wood samples and had different effects on wood mass‐loss rates depending on wood species. Higher minimum temperature and amplitude of relative humidity suppressed termite foraging intensity, with humidity having inconsistent effects on mass‐loss rates among wood species. Interestingly, microclimate outweighed biotic factors for Castanopsis eyrei but not for the other species. Three traits, that is, wood density, phenolics, and lignin content, were higher than the average for C. eyrei, making it the least attractive species for decomposers. Our findings suggest that species identity influences the effects and relative importance of biotic factors and microclimate for wood decomposition in subtropical forests. Furthermore, species identity effects are possibly mediated by multiple wood traits. Abstract in Chinese is available with online material.
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