Current Science

Nandan Singh ¹, Jeet Ram ¹, Ashish Tewari ¹, R. P. Yadav ²

Affiliations
1 Department of Forestry and Environmental Science, Kumaun University, Nainital 263 002, IN
2 Vivekananda Institute of Hill Agriculture, ICAR, Almora 263 601, IN

Abstract

Phenological events of rhododendron (Rhododendron arboreum Sm.) were monitored along elevation gradients in distinct ecological settings. The observations were carried out between 1500 and 2500 m elevation in Central Himalaya. The phenological events, i.e. bud formation, bud bursting, leafing, flowering, fruit formation and seed formation were recorded. Phenological duration and synchrony of all these phenophases were determined within site and along the elevation gradient in each study site. Our observations showed high synchrony throughout the elevation gradient, especially for peak flowering. Temperature, rainfall, age of the observed trees and site characteristics were related to initial and peak flowering dates. The circumference varied from 35.0 ± 2.73 to 140.0 ± 2.88 cm; similarly, height varied from 5.0 ± 1.02 to 16.5 v 1.41 m. All the phenological events began early at low elevation and were delayed at higher elevation. R. arboreum had a sharp flowering peak from January to March. Wet season flowering was rare, and seed formation occurred in summer. The climatic conditions affected the phenological characters of R. arboreum.

Keywords

Climate Change, Elevation Gradient, Phenology, Rhododendron arboreum.

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S. P. Singh ¹, A. Bhattacharyya ², Amit Mittal ³, Aseesh Pandey ⁴, Ashish Tewari ³, Avantika Latwal ⁵, Bency David ², Bhupendra S. Adhikari ⁶, Devendra Kumar ⁴, G. C. S. Negi ¹, Ishfaq Ahmad Mir ⁷, Krishna Kumar Tamta ³, Kumar Sambhav ⁵, Mayank Shekhar ², Mohit Phulara ⁵, Munisa Manzoor ⁷, Nandan Singh ³, Pankaj Tewari ¹, Parminder S. Ranhotra ², Pradeep Singh ⁵, Pratap Dhaila ¹, Priyanka Sah ⁵, Rahul Kumar ⁶, Rajesh Joshi ⁵, Ranbeer S. Rawal ⁵, Renu Rawal ⁵, Ripu Daman Singh ¹, Shruti Shah ³, Subrat Sharma ⁵, Subzar Ahmad Nanda ⁷, Surabhi Gumber ¹, Utsa Singh ¹, Zafar Reshi ⁷

Affiliations
1 Central Himalayan Environment Association, 6 Waldorf Compound, Mallital, Nainital 263 001, IN
2 Birbal Sahni Institute of Palaeosciences, 53, University Road, Lucknow 226 007, IN
3 Department of Forestry and Environmental Science, D.S.B. Campus, Kumaun University, Nainital 263 001, IN
4 G.B. Pant National Institute of Himalayan Environment and Sustainable Development, Sikkim Regional Centre, Pangthang, Gangtok 737 101, IN
5 G. B. Pant National Institute of Himalayan Environment and Sustainable Development (GBPNIHESD), Kosi-Katramal, Almora 263 643, IN
6 Department of Habitat Ecology, Wildlife Institute of India, P.O. Box 18, Chandrabani, Dehradun 248 001, IN
7 Department of Botany, University of Kashmir, Srinagar 190 006, IN

Abstract

This article enumerates the findings of a team research on the Indian Himalayan timberline ecotone, with focus on three sites (located in Kashmir, Uttarakhand and Sikkim). Timberline elevation increased from west to east, was higher in the warmer south aspect than the cooler north aspect, and was generally depressed. Betula, Abies, Rhododendron and Juniperus were important treeline genera. The Himalaya has not only the highest treelines (Juniperus tibetica, at 4900 m), but also the widest elevational range (>1700 m). Remotely sensed data revealed that the timberline is a long, twisting and turning ecotone, traversing a length of 8–10 km per km horizontal distance. Surface temperature lapse rate in the monsoonal regions was lower (–0.53°C/100 m elevation) than generally perceived and varied considerably with season, being the lowest in December. The Himalayan treeline species are not water-stressed at least in monsoonal regions, predawn tree water potential seldom getting below –1 MPa. The upward advance of Rhododendron campanulatum (a krummholz species) may deplete alpine meadows with climatic warming. Tree-ring chronology indicated that winter warming may be favouring Abies spectabilis. Early snowmelt increased growth period and species richness. Treelines generally are stable in spite of decades of warming. Dependence of people on timberline was still high; so economic interventions are required to reduce the same.

Keywords

Climate Change, Temperature Lapse Rate, Timberline Ecotone And Elevation, Tree Water Relation, Treeline Genera.

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