Dynamic biotic controls of leaf thermoregulation across the diel timescale

Does plant ecosystem thermoregulation occur? An extratropical assessment at different spatial and temporal scales

“…The input trait data are from Guo et al . (2022). The error bar indicates the 1.5× SD and refers to T c variability induced by the traits.…”

“…Finally, our EC‐ and satellite‐based findings of the magnitude of day‐time ∆ T variation (0–6°C) and associated underlying biotic importance (15–25%) are smaller than previous observations made on the leaf and canopy scale (Ehleringer et al ., 1976; Smith & Carter, 1988; Guo et al ., 2022). This can be caused by the effect of canopy structure (e.g.…”

“…Despite these limitations, our study has important implications for ecology, since upper canopies contribute a very large amount of carbon and water fluxes compared with the middle canopy and understory (Ellsworth & Reich, 1993). Other important physiological and morphological traits, such as leaf size and stomatal slope, shown to be tightly linked to ∆ T (Guo et al ., 2022), were not explored due to data limitations. Future attempts that leverage detailed traits by field measurements (e.g.…”

“…First, this is consistent with previous studies, as the night‐time T c vs T a relationship can be driven mainly by physical processes like longwave radiative cooling (although stomata still can open and regulate T c vs T a relationship at night, the extent of which remains largely uncertain; Sadok & Jagadish, 2020) and thus may not sufficiently reflect a plant canopy's thermoregulation capability (Mahan & Upchurch, 1988; Dong et al ., 2017). Second, the T c vs T a relationship at midday can best reflect thermoregulation differences between species or ecosystems since T c variability induced by plant traits normally peaks at this time (Guo et al ., 2022). Third, this maintains consistency between EC and satellite observations, as MODIS satellites measure LST at c .…”

“…wind speed and relative humidity (RH)) and biotic (e.g. PFT-specific physiological traits) factors that affect canopy transpiration also play a role in mediating T c remains largely underexplored (Jones, 2013;Still et al, 2021;Guo et al, 2022), especially on a continental scale. Thus, a comprehensive assessment of large-scale variability in plant thermoregulation occurrence and capability is critically needed.…”