Differences in leaf phenology between juvenile and adult individuals of two tree species in a seasonally dry tropical woodland

Abstract

In temperate forests, juvenile trees anticipate leaf phenology compared to adults, thus avoiding shading and herbivory. This is also expected to occur in seasonal tropical forests due to intense herbivory and shading during the rainy season; however, the anticipation of leaf phenology by juveniles in seasonal tropical forests has yet to be demonstrated. Stem‐succulent species are expected to be prone to juvenile phenological anticipation because these species are able to use water stored in their stems for leaf flushing in the dry season. We investigated this hypothesis by comparing leaf phenology (bud break, leaf expansion) of juveniles and adults of two species with contrasting wood densities in the transition between dry and rainy seasons in a tropical dry woodland. We also investigated the level of light limitation that juveniles experience in the rainy season. Both species exhibited bud break during the dry season, but only expanded their leaves with the occurrence of the first rains. In general, the stem‐succulent species had a more precocious bud break; however, anticipation by juveniles occurred only in the species with more dense wood. Canopy openness was lower than in temperate deciduous forests, but the fact that the full expansion of leaves occurred only with rainfall indicates that bud break in anticipation of canopy closure contributes only to keeping leaf photosynthetic balance from going negative, and not to higher carbon gain. The importance of anticipated budding for escaping herbivory remains an alternative explanation in need of investigation.

Exploring the role of biotic factors in regulating the spatial variability in land surface phenology across four temperate forest sites

“…For example, LMA differs significantly between tree and herbaceous species, as well as evergreen and deciduous species (Poorter et al ., 2009). Plant phenolics concentration, PAI, and canopy height have been shown to be important for distinguishing coexisting species (Asner et al ., 2012), representing forest composition (Hwang et al ., 2011), and reflecting the variation between age classes within a forest community (de Souza & da Costa, 2020), respectively. Moreover, several studies investigating the relationship between functional traits and phenology at the species scale suggest that functional traits can effectively predict species‐level phenology (Bucher & Römermann, 2021; Sporbert et al ., 2022).…”