Phenological Responses of Key Tree Species to Climatic Variables in Garhwal Himalaya

Phenological changes in tree species, influenced by climate change, have a major impact on ecosystem dynamics, especially in biodiverse areas such as the Garhwal Himalayas. This research examines the phenological trends of key tree species in the moist temperate forests of the Benog Wildlife Sanctuary. We monitored important phenological phases (leafing, flowering, and fruiting) from June 2021 to June 2023, taking observations bi-monthly and analyzing their relationship with climatic factors, including temperature and rainfall, using data collected from the Automated Weather Station installed at the location of the study. Circular statistical analysis indicated that while leaf emergence and decline followed a seasonal pattern, flowering and fruiting displayed varying seasonal trends depending on the species. Deciduous species like <i>Toona serrata</i> and <i>Pyrus pashia</i> showed prolonged periods of leafing and fruiting, whereas evergreen species such as <i>Machilus odoratissima</i>, <i>Cedrus deodara</i>, and <i>Pinus roxburghii</i> had shorter phenological phases. The fruiting phase also exhibited clear seasonal peaks, with the majority of species producing fruit between July and September. These results emphasize the specific phenological adjustments of different species to climatic conditions and highlight the importance of long-term monitoring to evaluate the effects of climate change on these ecologically vital species.