Research uncover long‐term effects of 7‐year warming experiment in the field on leaf hydraulic and economic traits of subtropical tree species

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  • Published: 2020-09-25
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Rising temperature associated with climate change may have substantial impacts on forest tree functions. We conducted a 7‐year warming experiment in subtropical China by translocating important native forest tree species (Machilas breviflora, Syzygium rehderianum, Schima superba and Itea chinensis) from cooler high‐elevation sites (600 m) to 1–2°C warmer low‐elevation sites (300 and 30 m) to investigate warming effects on leaf hydraulic and economic traits.

Under the supervision of Prof. LIU Xiuju at South China Botanical Garden of Chinese Academy of Sciences, PhD student WU Ting at University of Chinese Academy of Sciences reported data from the last 3 years (Years 5–7) of the experiment. Warming increased leaf hydraulic conductance of S. superba to meet the higher evaporative demand. M. breviflora (300 m), S. rehderianum, S. superba and I. chinensis (300 and 30 m) exhibited higher area‐based and mass‐based maximum photosynthetic rates (Aa and Am, respectively) related to increasing stomatal conductance (gs) and stomatal density in the wet season, which led to rapid growth; however, researchers observed decreased growth of M. breviflora at 30 m due to lower stomatal density and decreased Aa in the wet season. Warming increased photosynthetic nitrogen‐use efficiency and photosynthetic phosphorus‐use efficiency, but reduced leaf dry mass per unit area due to lower leaf thickness, suggesting that these tree species allocated more resources into upregulating photosynthesis rather than into structural investment. The findings highlight that there was trait variation in the capacity of trees to acclimate to warmer temperatures such that I. chinensis may benefit from warming, but S. superba may be negatively influenced by warming in future climates. This work was published in Global Change Biology.