Stand Transpiration Estimates from Recalibrated Parameters for the Granier Equation in a Chinese Fir (Cunninghamia lanceolata) Plantation in Southern China

Abstract

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is an important native tree species that is widely distributed in subtropical areas of southern China and cultivated for wood extraction. However, information on water use by Chinese fir plantations is still scarce. In this study, we performed species-specific parameter calibrations for the original Granier equation for sap flow density (SFD) estimates. Stand transpiration (E s ) was related to environmental inputs, such as rainfall, air temperature (T a ), vapor pressure deficit (VPD), photosynthetically-active radiation (PAR), air relative humidity (RH), and potential evapotranspiration (PET) in order to examine how environmental factors affect the E s of Chinese fir plantations. According to our results, Granier's original parameters set underestimated C. lanceolata SFD by up to 54% compared to our species-specific calibrated parameters set. A strong positive correlation was found between SFD, diameter at breast height (DBH), and tree height among trees populations. The total E s in 2015 was 522.1 mm, with obvious seasonal dynamics and an average of 1.4 mm·day −1 . Daily and monthly E s were positively correlated with VPD, PAR, T a , and PET. A negative relationship between E s and RH was detected only at a daily timescale. Our findings indicate that the original Granier equation requires a parameter calibration when it is applied to species-specific thermal dissipation probe (TDP) estimates, and our findings can also provide novel insights on the water use of Chinese fir in major wood production areas in Southern China.

Assessing Environmental Control of Sap Flux of Three Tree Species Plantations in Degraded Hilly Lands in South China

“…This could also be explained by the thick wax layer on the leaf surface of C. lanceolata [61]. Although Zhang et al (2016) [62] found a similar J s of C. lanceolata with similar DBH to our results in Southwest China, the J s of C. lanceolata was much smaller than reported for other locations in southern China [61,63]. Moreover, Li and Ritchie (1999) [64] reported that C. lanceolata requires well-drained soil and that it will not grow well in wet conditions.…”

Inconsistent Responses of Transpiration of Different Canopy Layers to Simulated Canopy and Understory N Depositions in a Low‐Subtropical Evergreen Broadleaf Forest

“…also found that soil water content compensates forest transpiration in dry season Ouyang et al (2018). …”

“…Transpiration is generally considered as a wasteful but unavoidable consequence of photosynthesis, accounting for 20%-65% and under certain circumstances even more than 80%-90% of terrestrial evapotranspiration (Jasechko et al, 2013). Accurate estimates of forest transpiration, as well as an examination of its affecting factors, are critical for understanding the effects of forest characteristics on hydrological processes and watershed water resources management (Ouyang et al, 2018). The increase of nitrogen source reduces N limitation of tree growth, which can drive and enhance the carbon intake of forest, and would in turn influence the regional water balance due to the alternation of tree water use based on CO 2 /H 2 O coupling (Domec et al, 2009;Guerrieri et al, 2010).…”

Intra-Annual Wood Formation of Cryptomeria fortunei and Cunninghamia lanceolata in Humid Subtropical China

“…This can explain why C. fortunei and C. lanceolata could maintain a relatively high growth rate and cell increment during the summer of 2016, and a higher growth rate during spring in 2017 (Figure 4 and Supplementary Figure 5). In 2017, the high VPD accompanied by high temperatures in the study area from July to August is likely to aggravate the transpiration of the trees, which may lead to a decrease of stomatal conductance and limited photosynthesis (Mathur et al, 2014;Zhou et al, 2015;Ouyang et al, 2018;Grossiord et al, 2020;Song et al, 2020). These conditions may cause a decrease in carbohydrate availability and a decreased growth rate (Michelot et al, 2012;Zhang et al, 2021).…”