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Traits mediate drought effects on wood carbon fluxes
Author(s) -
Hu Zhenhong,
Chen Han Y. H.,
Yue Chao,
Gong Xiao Ying,
Shao Junjiong,
Zhou Guiyao,
Wang Jiawei,
Wang Minhuang,
Xia Jianyang,
Li Yongtao,
Zhou Xuhui,
Michaletz Sean T.
Publication year - 2020
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.15088
Subject(s) - decomposer , nitrogen , water content , ecosystem , moisture , carbon fibers , decomposition , environmental science , botany , biology , ecology , chemistry , materials science , geotechnical engineering , organic chemistry , composite number , engineering , composite material
CO 2 fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO 2 fluxes. Here, we examined the responses of CO 2 fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO 2 fluxes, but its effects varied with both taxonomical group and drought intensity. Drought‐induced reduction in wood CO 2 fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO 2 fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO 2 fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition.