Intra-annual radial growth and its climate response for Masson pine and Chinese fir in subtropical China

Diel and seasonal stem growth responses to climatic variation are consistent across species in a subtropical tree community

“…3), and that this pattern was driven by the diel pattern of stem growth occurrence (Figs 3, S2). Our results for subtropical trees are in line with the findings for broadleaf and conifer trees in temperate forests (Ziaco & Biondi, 2018; Meng et al ., 2021; Zweifel et al ., 2021) where stem growth peaked before dawn due to high growth occurrence when trees were replenished with water, and declined rapidly in the morning hours (Zweifel et al ., 2021). In conclusion, diel patterns in growth occurrence lead to large stem growth before dawn and thus drive the diel patterns in growth contribution across 14 subtropical broadleaf species.…”

“…S4). The shifts in diel growth patterns over the season suggest that moist atmospheric conditions mitigated water limitation and allowed growth to take place during the daytime (Aldea et al ., 2018; Ziaco & Biondi, 2018; Meng et al ., 2021). Nevertheless, this seasonal shift was relatively small and growth occurrence predominantly occurred before dawn.…”

“…Studies measuring intra‐annual stem growth patterns using dendrometers have provided insights on the environmental drivers of intra‐annual stem growth, in particular vapour pressure deficit (VPD), soil moisture (Etzold et al ., 2021) and air temperature (Tumajer et al ., 2022). Most dendrometer studies were conducted in temperate forests (Oberhuber et al ., 2014; van der Maaten et al ., 2018; Etzold et al ., 2021; Tumajer et al ., 2022), but knowledge on climatic drivers of intra‐annual stem growth dynamics for tropical and subtropical climate zones is very poor (Krepkowski et al ., 2010; Wagner et al ., 2016; Meng et al ., 2021; Kaewmano et al ., 2022). One of the challenges for dendrometer studies in these species‐rich systems is that community‐level growth responses cannot be easily estimated by measuring a single or few dominant species, as is usually done in species‐poor temperate forests (Oberhuber et al ., 2014; van der Maaten et al ., 2018; Etzold et al ., 2021; Tumajer et al ., 2022).…”

“…So far, such patterns have been investigated for a limited number of species from temperate climates (De Swaef et al ., 2015; van der Maaten et al ., 2018; Etzold et al ., 2021; Zweifel et al ., 2021; Tumajer et al ., 2022). Such diel patterns with strongest growth at night may however vary over seasons and across climate regions due to the variability in growth conditions and forest composition (Aldea et al ., 2018; Ziaco & Biondi, 2018; Meng et al ., 2021), but remain poorly explored for tropical and subtropical forests.…”

TreeNet–The Biological Drought and Growth Indicator Network

“…Uncertainty also remains with the assumption of the zero-growth concept that no growth takes place in the case of stem shrinkage, which means that the turgor necessary for growth is not achieved (Zweifel et al, 2016) and no cell expansion is possible under such conditions. Even though the underlying concept of Lockhart (1965) is theoretically sound and many recent papers have provided evidence for its usefulness (Dietrich and Kahmen, 2019;Schafer et al, 2019;Aryal et al, 2020;Eitel et al, 2020;Güney et al, 2020;Lamacque et al, 2020;Pappas et al, 2020;Sellier and Segura, 2020;Dukat et al, 2021;Meng et al, 2021;Nehemy et al, 2021;Pierrat et al, 2021;Zweifel et al, 2021), the separation of dendrometer data into GRO and TWD has not yet been tested with an independent method. The main reason for this lack of rigorous testing is that there is no alternative method capable of cross-checking hourly resolved dendrometer data in mature forest trees over a reasonable period of time (i.e., without excessive destructive sampling).…”