Paper data of "Linking leaf dark respiration to leaf traits and reflectance spectroscopy across diverse forest types" in New Phytologist

Leaf dark respiration (Rdark) is an important but minimally quantified component of carbon cycling in forest ecosystems. In terrestrial biosphere models, it is typically simulated through leaf traits such as maximum carboxylation capacity (Vcmax), leaf mass per unit area (LMA), nitrogen and phosphorus concentrations. However, the effectiveness of these relationships between different forest types still needs to be thoroughly evaluated. We collected canopy leaves of three typical temperate (mountain Changbai, 42°23' N, 128°05' E), subtropical (mountain GT, 29°15' N, 118°07' E) and tropical (Xishuangbanna, 21°37' N, 101°34' E) forests in China through the Chinese Academy of Sciences canopy tower crane observation network. Rdark and Vcmax were measured using a portable photosynthesis measurement system, leaf reflectance spectra were measured using a portable ground spectrometer, and leaf morphology and biochemical traits were measured using conventional laboratory methods. We found that leaf magnesium and calcium concentrations are more important in explaining cross site Rdark than commonly used traits such as LMA, nitrogen and phosphorus concentrations, but the univariate trait Rdark relationship remains weak (r2 ≤ 0.15) and varies depending on the forest. Although the multivariate relationship of leaf traits improves model performance, leaf spectroscopy outperforms trait Rdark relationship, accurately predicting cross site Rdark (r2=0.65) and identifying factors that lead to Rdark variation. Our research findings reveal some new traits with greater cross site scalability, challenging the use of empirical trait Rdark relationships in process models, and emphasizing the potential of leaf spectroscopy as a promising alternative method for estimating Rdark, ultimately improving the modeling of terrestrial plant respiration processes.