Climate Variability and Associated Response of <i>Larix griffithii</i> in Kanchenjunga Conservation Area of Nepal

Abstract

Mountains are most sensitive to climate change and the impacts are already evident in different sphere and sector of mountain regions, especially in the vulnerable countries like Nepal. This research was designed to integrate hydro-climatic data analysis and climate sensitivity through dendrochronology to generate an understanding on how Larix griffithii, one of the least studied conifers in Nepal, is responding to climate variability and change. A significant warming trend of 0.021°C year -1 was observed in the region. Precipitation was more erratic without any significant increasing, decreasing or cyclic trend. Between 1962 and 2012, the warmest year on record was 2010 while 1997 was the coolest year on record. After 1997 a clear shift in temperature regime was observed with the recent decade experiencing a sharp increase in temperature. A site chronology extending 1745-2015 AD was prepared. Very strong significant correlation was observed between the standard chronology and monthly temperature especially in summer months indicating a potential for summer months' temperature reconstruction. The reconstructed summer month's temperature data for the period 1770-2015 captured 34% variability. The short cold episodes were observed around the 1810s, 1910s, and 1970s while warm periods were observed around 1890s, 1920s and 2000s. Radial growth of Larix griffithii in the site shows a highly significant negative relationship with the monthly temperature of the previous year and current year summer months especially for June, July, August, September of previous year and July, August and September of the current year. Significant positive correlation was observed for both previous year and current year July precipitation. The summer temperature coupled with precipitation is seen to limit the tree growth through moisture limitations. With the temperature in increasing trend, it is likely that the growth of Larix will face more heat stress in future, making them more dynamic to the changing climate.

The relationships among structure variables of larch forests in China

“…Zhang et al (2013) found that average DBH and stem density of the L. gmelinii in northeastern China were largely determined by precipitation of the driest quarter. Bhatta et al (2018) found that radial growth of the L. griffithii was significantly positively correlated with the precipitation of the wettest quarter and negatively correlated with the mean temperature of the warmest month in Nepal near the Tibetan Plateau. Meanwhile, the growth response of larch to climatic conditions depends on altitude (Sun et al 2010b).…”

Population structure and regeneration of Himalayan endemic Larix species in three high-altitude valleys in Nepal Himalaya

“…Climate change is expected to directly alter the composition of communities and the functioning of ecosystems across the globe (Mokany et al 2015). Recent studies (Bhatta et al 2018;Aryal et al 2020) have already shown the influence of climate on growth of Larix species in Nepal Himalaya. Phenophase adjustments such as flower initiation of Larix himalaica was noted in LNP (Kunwar 2011).…”