Biological and environmental controls on nighttime water-use behaviors in Populus simonii in semi-arid areas of the Chinese Loess plateau

Quantification of Nocturnal Water Use and Its Composition in a Eucalyptus urophylla × E. grandis Plantation on the Leizhou Peninsula, South China

“…Nevertheless, 17.35% of Tn remained unexplained. This may be partly due to the effect of our method of determining baseline fluxes, and partly due to the fact that our model only considered the influence of environmental factors on Tn, whereas Tn may also be affected by leaf water potential and the regulatory effects of some as yet unidentified intrinsic physiological processes (Chen et al, 2020;Dai et al, 2024). Generally, however, our method's results in splitting Tn and Re are satisfactory.…”

“…However, the J d cannot reach zero every day due to Tn and Re, so using the daily maximum values of ΔT as ΔT max could lead to an underestimation of Q night (Di et al, 2022;Lu et al, 2004). Therefore, we used the Granier's double regression method to determine ΔT max to find the optimal baseline flux (Dai et al, 2024;Granier et al, 1994;Lu et al, 2004). The specific steps and principles are as follows: (a) the local maxima of ΔT were determined for each day from 20:00 to 5:30, as the time with solar radiation <5.0 W m 2 and low VPD was most likely to have a potential ΔT max in this study; (b) the linear regression between local maxima of ΔT and day of year in moving 7-10 days periods was performed and the maxima of ΔT below the regression line were removed; (c) a new linear regression was performed based on the remaining data points to calculate the ΔT max for this moving time window; (d) ΔT max should be determined separately for each sensor.…”

“…Global climate change is profoundly affecting the water cycle in terrestrial ecosystems (Dai et al, 2024;Kropp et al, 2017). Tree water use is one of the critical ecohydrological processes (Di et al, 2022;Peters et al, 2010) that link the water, carbon, and energy cycles.…”