Assessing the Priorities for Sustainable Forest Management in the Sikkim Himalaya, India: A Remote Sensing Based Approach

Abstract

Sikkim is a small, mountainous, Indian state (7,096 km 2 ) located in the eastern Himalayan region. Though a global biodiversity hotspot, it has been relatively less studied. A detailed forest type, density and change dynamics study was undertaken, using SATELLITE remote sensing data and intensive field verification. The landscape was found to be dominated by alpine and nival ecosystems, with a large portion above the tree line, considerable snow cover, and a sizeable area under forest cover (72%, 5,094 km 2 ). A total of 18 landscape components including 14 vegetation classes were delineated, with the major ones being oak forest, alpine meadow, alpine scrub, conifer forest and alder-cardamom agroforestry. Of the 3,154 km 2 of forests below the tree line, 40% were found to be dense (>40% tree canopy cover). A sizeable portion of the non dense forests below the tree line was contributed by the degradation of oak forests, which was confirmed by change detection analysis. However on a positive front over the past decade, ban on grazing and felling of trees in forests has been implemented. In order to expand the extent of dense forests, further efforts are needed for the restoration of oak forests such as fire protection, providing alternatives to firewood use, promotion of alder-cardamom agro-forestry in the private lands and protection of the small-sized, fragmented forest patches in the subtropical belt.

Assessing Forest Structure and Composition along the Altitudinal Gradient in the State of Sikkim, Eastern Himalayas, India

“…However, between forest types, the low-altitude forests completely lacked trees above 93 cm diameter, a scenario undesirable for a sustainable forest. The finding could be associated with forest degradation and deforestation reported by earlier studies [47,61]. One potential factor for the absence of large trees could be the practice of cardamom cultivation mainly in the low-altitude forest of Sikkim.…”

“…with Mount Kanchendzonga-the third highest peak in the world. The complex topography and enormous altitude are characterized by 12 major vegetation types, from a tropical warm broad-leaved forest at the lowest altitude to alpine meadow at the highest altitude [47]. It has a subtropical to temperate climate, with annual rainfall between 2700 mm to 3200 mm, and the mean annual temperature (MAT) varies from 8.4 • C to 23.2 • C [48].…”

“…to 3200 m a.s.l. The forests were selected because, forests within the range has undergone significant loss in forest cover [47]. Thus, quantitative assessment of these forests is imperative to plan conservation strategies.…”

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

“…The regeneration of the plant is the key ecological process in a forest ecosystem in which seeding and sprouting of woody species are involved (Pratt et al 2012). One of the most important problems that mountainous forests are experiencing is poor regeneration (Karauchi et al 2000), which is especially observed in subalpine forests in Eastern Himalaya (Tambe et al 2011;Pandey et al 2018) as well as in Western Himalaya (Rai et al 2012). Poor regeneration and naturally slow growing nature of Larix griffithiana are documented in subalpine forests in Sikkim Himalaya (Tambe et al 2011) and absence of seedlings and saplings of the species has been recorded in temperate forests in Lachung Range of the Sikkim Himalaya (Subba et al 2015).…”

“…Sustainability of populations with inadequate number or lack of regenerating individuals has been reported to be challenging for several species of subalpine trees. Examples include Larix potaninii in China (Taylor et al 1996;Cui et al 2017;Liang and Wei 2020), Larix griffithiana in Sikkim, India (Tambe et al 2011;Subba et al 2015), and Bhutan (Moktan 2010); and for many other species in the eastern Himalaya (Pandey et al 2018), Nepal Himalaya (Vetaas 2000;Shrestha et al 2007;Kunwar 2011;Sujakhu et al 2013;Maren et al 2015;Suwal et al 2016), and western Himalaya (Rai et al 2012). Therefore, for the effective conservation of the typical Himalayan vegetation of Larix forests, efforts need to be concentrated both locally and regionally.…”