Dormancy characteristics of lammas-growth seedlings of subtropical trees and their phenological responses to experimental warming.

This article investigates the effects of lammas growth—defined as additional shoot growth after growth cessation and bud set in late summer—on bud burst phenology and dormancy traits in four subtropical tree species: Carya illinoinensis, Cinnamomum japonicum, Phoebe chekiangensis, and Torreya grandis. The study found that, except for C. illinoinensis, lammas-growth seedlings exhibited delayed bud burst under ambient conditions, linked to increased dormancy depth and higher forcing requirements. However, experimental warming revealed that lammas-growth seedlings had greater sensitivity to spring temperatures, which reduced the difference in bud burst timing between lammas-growth and non-lammas-growth seedlings under elevated temperatures. These findings highlight the complex influence of lammas growth on dormancy dynamics and phenology in subtropical trees, emphasizing the need for further research to understand its implications under climate change.