Assessing Ecosystem Service Potentials of Trees Outside Forests (TOF) Along Altitudinal Gradients in the Eastern Himalayas

Abstract

Teak forestry plantations are a critical TOF system that provides numerous ecosystem services. In this study, 30 teak forestry plantations in the foothills of the Indian Eastern Himalayas were examined to understand the ecosystem services provided by trees through direct observation, farmer interviews, and secondary validation using published literature
and ethnobotanical databases. A total of 26 tree species were identified
from the plantations. Species richness was higher at low altitudes, followed by mid and high altitudes. The study documented 81 provisioning services, 22 regulating services, 64 cultural services, and 56 supporting
services. Species such as Albizzia lebbeck, A. procera, Melia azedarach, Acacia auriculiformis, Neolamarckia cadamba, and Alstonia scholaris contributed the highest number of services. The extent of ecosystem services provided by teak plantations varies with altitude. The highest
number of provisioning services was observed in teak plantations at low altitudes, followed by those at mid and high altitudes. Conversely, the highest number of cultural services was reported from high-altitude plantations, with fewer at low and mid altitudes. These findings highlight the varied roles of trees across different altitudinal zones and the importance of multifunctional tree-based land management systems in delivering ecosystem services. Further research is needed to accurately quantify the economic value of these ecosystem services.