For T 50, we found significant species (F = 7.98, P = 0.0007) and season (F = 6.69, p =0.022) effects (Supporting Information Table S3). A. guianensis was significantly different from the rest of the species except T. altissima . End of dry period T50 for all species combined was ~ 1.6°C higher at 51.6±0.8 °C compared to the wet period that averaged at 49.4±0.6°C. A. guianensis showed the highest seasonal plasticity in T50 whileB. rubescens the least. A. guianensis recorded the highestT50 during both at the end of dry (56.4±0.5 °C) and wet (53.2±0.6 °C) periods (Figure 3B). Compared to the rest of the species studied, T50 for A. guianensis was 6.4°C (P = 0.001, \(t_{14}\) =5.08) and 4.1°C (P = 0.016,\(t_{21}\) = 2.61) higher during the end of dry and wet seasons respectively. Excluding A. guianensis, there was no significant difference across species in T50 during both seasons. It is important to note that all species had mature, fully expanded leaves except for H. courbaril, which had a young flush of leaves during the end of the dry period. However,T50 for H. courbaril was not different from the pool of species excluding A. guianensis .
T95 averaged 60.1±0.2 °C across species during the end of the dry period and 57.3±0.3 °C during the wet period. Although the ranges differed, the difference in means across the season of 2.9 °C was not statistically significant (Figure 3C). The recovery ofFv /Fm , measured 24h after heat treatment following a 30-minute duration dark period and found no significant recovery upon incubation under the irradiance conditions used (< 20 µmol m-2 s-1and ~25°C room temperature) inT50 (t50 = 1.23, P= 0.22), T5 (t50 = –0.81,P = 0.42) or T95 (t48 = 1.97, P = 0.059).