Impacts of Climate Change on Phenology of Five Evergreen Tree Species on Doi Suthep

Plant growth and development patterns, including flowering, fruiting, or leaf senescence, correspond with environmental factors and these patterns are usually on seasonality. Current changes in climate could be factors affecting plants. Therefore, this study was aimed to monitor and collect phenological data of tree species in an evergreen forest for 12 months, then compare the data with past phenological data, also climatic factors. Five tree species were monitored and collected data monthly from April 2023 to March 2024 using the crown density method and climatic differences between past and present were analyzed using the t-Test. It's found that there were significant differences between the past and the present average air temperature and relative humidity. Vegetative phenology showed that most tree species shed their leaves less frequently than in the past. There were also changes in reproductive parts: Cryptocarya amygdalina started flowering later than usual and had no fruiting phenophase, Garcinia mckeaniana had no fruiting after flowering phenophase, and Magnolia baillonii's flowering phenophase were found shorter than in the past. It's concluded that climate change could impact on plant development patterns. The phenological data can be used for seed collection planning, which is important for forest restoration.