The addition of new nodes to shoots is an essential mechanism for understanding and modelling canopy growth but surprisingly, there is very little research on the factors that control the phyllochron in tree species. It is often assumed that the phyllochron is regulated by temperature and is consistent among all shoot types. A new study published in AoB PLANTS by Davidson et al. clearly indicates that this is not the case. Their study shows differences in the phyllochron between different shoot types and water treatments that appear to be associated with rank effect rather than temperature.
Davidson, A., Da Silva, D., & DeJong, T. M. (2017). The phyllochron of well-watered and water deficit mature peach trees varies with shoot type and vigour. AoB PLANTS, 9(5). http://dx.doi.org/10.1093/aobpla/plx042