Using seasonal measurements to inform ecophysiology: extracting cardinal growth temperatures for process-based growth models of five Eucalyptus species/crosses from simple field trials

Abstract

Background: Development of a relatively simple growth modelling approach for plantation species that allows derivation of cardinal (base, optimum and ceiling) air temperatures for growth, whilst accounting for changes in organism size, would represent a considerable advance over existing models. Such an approach would provide insight into species phenology and, in an agronomic setting, allow growers to closely match species to sites. Here, a model is described that can be used to predict seasonal variation in growth and cardinal air temperatures from simple seasonal measurements at a single site. Methods: The model was applied to data from an irrigated trial comprising two Eucalyptus species and three Eucalyptus crosses. Using measurements of mean daily air temperature data and stem volume, taken over a two year period, the model was fitted to the data and used to estimate cardinal air temperatures for the five species/crosses. Results: The model predictions corresponded well to the actual data for all five species/crosses, with R 2 ranging from 0.993 to 0.999. The optimum air temperature, T o , for E. camaldulensis x E. globulus of 26.9°C significantly exceeded T o for the other four species/crosses, where T o ranged from 15.4 to 18.7°C. As T o for E. camaldulensis x E. globulus was close to the highest mean daily air temperature recorded at the study site, the air temperature modifier for this species was almost always sub-optimal and consequently this cross was not well matched to the site. In contrast, T o for the other four species/crosses were considerably closer to the mean air temperature of the site with T o for E. nitens most closely approximating the mean air temperature (15.4 vs. 13.0°C).

A common garden experiment examining light use efficiency and heat sum to explain growth differences in native and exotic Pinus taeda

“…A more detailed modeling effort (e.g. (Campoe et al, 2013;Watt et al, 2014) will be required to better determine the magnitude of the weather effect; the sites in this study will provide the opportunity to calibrate a model to better examine this hypothesis. We identified site related growth differences at three sites where the same genetic material was planted in native and exotic locales.…”

Differences in early seasonal growth efficiency and productivity of eucalyptus genotypes

“…As radiation is an essential resource for photosynthesis, its low availability results in decreased plant metabolism, which affects plant growth (Whitehead and Beadle 2004). In addition, lower winter temperatures (sometimes below 0 °C in our study) are known to affect forest productivity (McMurtrie et al 1994;Watt et al 2014). The pattern of eucalyptus growth as the plantation aged showed similar strategies of resource acquisition dynamics and allocation among taxa and genotypes (le Maire et al 2019).…”

“…We estimated the individual tree volume (VOLt-cm 3 ) as a cone volume (Rubilar et al 2020;Watt et al 2014). The current monthly increment (CMI; cm 3 tree −1 month −1 ) was estimated as the difference between VOLt at the beginning and end of each season.…”

Water and Temperature Ecophysiological Challenges of Forests Plantations under Climate Change

“…Understanding species-specific and/or genotypic responses to temperature extremes and the duration of such stresses is critical for predicting plantation responses under climate change. Detailed phenological studies, such as those developed by Watt et al [65] and Queiroz et al [66], that evaluate optimal, minimum, and maximum performance temperature limits, or cardinal temperatures, for several tropical and Mediterranean eucalyptus species, may provide a basis for understanding key CC-related effects on growth performance of tree species and genotypes (Figure 2). Major changes in vegetation phenology have been observed in several ecosystems due to earlier warmer temperatures throughout the seasons, causing an earlier start to the growing season and increasing stand growth and carbon fixation [67,68].…”