Dendrochronological studies in the western Himalaya: opportunities, challenges and prospects

Numerous studies involving tree rings have been conducted in the Himalayas on a wide variety of species for paleoclimate reconstructions. Each species responds differently to precipitation and temperature variability in different ecological settings. Therefore, an improved understanding is required to reconcile the mechanisms behind the different responses of tree growth with changing climate regimes. The review is focused primarily on the studies undertaken in the field of dendrochronology in the western Indian Himalayan region (WIH) and explores the relationships between climate and forest response. The study embraces a dual strategy by surveying the literature of tree-ring studies conducted in WIH and using metadata to synthesize results and their global implications. Our review reveals that 553 years (A.D. 1452–2004) long tree-ring chronologies from high altitudes in WIH have indicated anomalous higher tree growth in the recent past strongly associated with warming trends over the region. Correlation and response function analysis between tree-ring widths and climatic parameters have shown a significant negative correlation with pre-monsoon March–April–May (MAM) temperature and a positive correlation with precipitation during the same period in the region influenced mainly by Indian summer monsoon (ISM). However, a positive correlation with winter months’ temperature has also been observed owing to the availability of water from snowmelt due to increased warming trends. Of all the potential datable tree rings, Cedrus deodara was the most studied tree species followed by Pinus spp. while Betula utilis was the least studied.