Changes in soil chemistry and foliar metabolism of Himalayan cedar (Cedrus deodara) and Himalayan spruce (Picea smithiana) along an elevational gradient at Kufri, HP, India: The potential roles of regional pollution and localized grazing
We investigated changes in soil chemistry and foliar metabolism of Himalayan cedar [ Cedrus deodara (Roxb. Ex Lamb.) G.Don] and Himalayan spruce [ Picea smithiana (Wall.) Boiss] trees along a steep elevational gradient in the lower Himalayan Mountains at Kufri, Himachal Pradesh (HP), India. The foliar and soil samples were collected from four locations along a 300 m elevational gradient at ridge, high-, mid-, and low-elevation sites within the forested Shimla Water Catchment Wildlife Sanctuary that provides water for the city of Shimla, HP,. Observations at the time of sampling revealed that the high-elevation site was being heavily grazed. Soils collected at the four sites showed differences in soil chemistry along the gradient. Surface soils (top 10 cm) at the high-elevation site had the highest concentrations of carbon, nitrogen, calcium, magnesium, phosphorus, organic matter, and effective cation exchange capacity, possibly caused by grazing. Mineral soils were slightly acidic at all sites except the mid-elevation site, which was extremely acidic in the upper mineral soil. Similar to surface soil chemistry, foliar metabolism was also comparatively unique for high elevation. In Himalayan cedar foliage, higher concentrations of soluble proteins, polyamines, amino acids, and potassium were observed at the high-elevation site as compared to the ridge, mid and low elevations. No major differences were observed in the metabolic profiles of cedar between the ridge and low elevation ranges. Spruce foliage was sampled only from the ridge and low elevations and its metabolic profiles suggested healthier conditions at the low elevation. The results of the study demonstrate the impact of the interplay between local and regional drivers of forest health on cedar and spruce trees in a forested catchment that acts as a water source for downstream communities.