Analyzing climatic and Non-Climatic impacts on Structure, phenology and functions of Western Himalayan forests

• Under the current challenges in Western Himalaya, pine forests have a maximum tree densities. • Deodar forests have a maximum aboveground biomass in Western Himalaya under current challenges. • The carbon stocks were minimum in the oak forests of the Himalaya under the current challenges. • Invaders have threatened native plant richness, with 297 naturalized alien plant species by now. • Significant changes in plant phenology, with advance blooming and upward shifts in tree lines, occurred in Himalaya. The Himalayan forests are critically threatened by climatic and non-climatic drivers, resulting in significant alterations in the ecological balance. This study attempted to analyze the key ecological features and threats to the west Himalayan Forest ecosystem by systematically analyzing 614 Scopus-indexed articles published over the last three decades. Pine forests exhibit maximum tree densities, ranging from 153 to 1,675 trees/ha, while Banj oak forests demonstrate densities of 250 to 1,500 trees/ha. Moru Oak forests possess maximum aboveground biomass ranging from 500-989 Mg/ha, and maximum carbon stocks of 30–445 Mg/ha. Climate change has facilitated the proliferation of invasive species in the region, threatening native biodiversity. Invasive species like Lantana camara and Ageratina adenophora display broad altitudinal adaptability. The increasing number of fire incidents driven by human activities and climate change is another major threat to forests. Multiple reports of phenological shift such as early flowering and fruiting in Rhododendron arboreum and Myrica esculenta , and upward treeline shifts, are visible impacts of climate change in the region. These impacts highlight the necessity for integrated research to develop effective adaptation strategies and conservation measures in the region. Sustainable management practices based on an in-depth ecological understanding of the forest ecosystem under the prevailing threats will facilitate the conservation and identification of critical ecosystem-based approach (EbA) in the western Himalaya.