Abstract: The study was conducted in the Benog Wildlife Sanctuary of Mussoorie forest division in Uttrakhand state of India. Studied forest is dominated by Quercus leucotrichophora (banj oak) species which is native and one of the most important Himalayan species that supports rich biodiversity. The research was focused to understand the impact of elevational gradient on morphological and chemical leaf traits of banj oak in the Western Himalayan forest. It was hypothesized that increasing elevation would change the leaf traits for better adaptation to changing climatic conditions. Objective of the study was to measure the changes in leaf morphological and chemical traits along the elevational gradient.
Study site was divided into three elevation ranges i.e. 1550 – 1750 m (E1), 1750 – 2050 m (E2) and > 2050 m (E3). At each elevation, seven sites were selected and at each site five trees were chosen for the leaf sampling. From each tree five leaves were collected to measure the leaf traits. Thus a total of 525 leaf samples were collected. Traits such as leaf area (LA), Specific leaf area (SLA), Leaf thickness (Lth), Leaf dry matter content (LDMC), carbon (C), nitrogen (N), calcium (Ca), sodium (Na) and C/N ratio were considered for the study.
During study, it was found that LA and SLA is decreasing with elevation (p < 0.001). Higher elevation is exposed to more sunlight therefore, plants reduce their leaf area to save construction cost whereas, SLA which represents the growth was also found decreasing due to harsh conditions. However, Lth and LDMC is increasing with elevation (p < 0.001). LDMC shows resistance of plant to harsh conditions and is important for defense mechanism of plant whereas, thicker leaf helps to tolerate severe winter. Therefore, both the traits increased with higher elevation. Leaf nitrogen content was found decreasing with elevation due to lower growth rate which is associated with SLA. C/N ratio was found to be increasing because concentration of C was not changing and nitrogen was decreasing with elevation.
The present study shows that morphological and chemical traits changes with varying elevation due to changing climatic conditions. This affirms the hypothesis that banj oak forests are well adapted in the climatic conditions of Western Himalaya. This adaptation to harsh conditions make them a successful and important species of the region. Therefore, future of banj oak will depend on their capability to adapt new strategies as per global climate change scenarios.
