Modeling the initial development dynamics for two native Brazilian forest tree species

Abstract Development models are used to quantify the dynamics and rate of initial development, the seedling phase duration, and global warming impacts on forest species. Such models relate the physiological age of the plant, through air temperature functions, to its morphological appearance, given by the cumulative leaf number on the main stem. Despite their potential, studies on initial development dynamics are still scarce, especially for native forest species. Thus, this study calibrated and evaluated the performance of two development models—Phyllochron and Wang and Engel—in estimating the cumulative leaf number and seedling phase duration of two Brazilian native forest species—Cybistax antisyphilitica (Mart.) Mart. (Bignoniaceae) and Platycyamus regnellii Benth. (Fabaceae). Cumulative leaf number and seedling phase duration data from outdoor experiments carried out during the 2017 and 2018 growing seasons with 12 sowing dates in Itajubá, Minas Gerais, Brazil, were used. These experiments provided a rich dataset for calibrating and evaluating the Phyllochron and Wang and Engel development models. Both development models were capable of predicting cumulative leaf number with low and acceptable errors for both species and produced less accurate estimates for seedling phase duration. For C. antisyphilitica, both models were remarkably similar in estimating cumulative leaf number and seedling phase duration, with a root-mean-square error of 3.3 leaves and 25 days, respectively. For P. regnellii, the Wang and Engel model was slightly better than the Phyllochron, with an error of fewer than 2.06 leaves and 13.1 days. Using the coefficients calibrated in this study and, preferably, the Wang and Engel model, it is possible to project the development of both forest species under climate change scenarios.