Passive restoration considerably improved the community structure, soil health and carbon stock in the Pine forests of Kashmir Himalaya, India

Abstract

Forest restoration significantly enhances soil quality, carbon stock and improves community characteristics, but reports from temperate coniferous ecosystems are limited. The present research aimed to study the changes in vegetation characteristics, biomass, and soil health after eight years of restoration in coniferous forests of Kashmir Himalaya, India. The studied forest stands include the sites before restoration (IN), restored forests (RT) and non-restored (NR) control plots. The results exhibited similar soil texture (clay-loam) in both RT and NR, albeit soils under RT had lower acidity (6.03 ± 0.11) and bulk density (1.21 ± 0.07 Mg m−3) than NR. The average total nitrogen, soil organic carbon, and available phosphorus were 13.2, 32.7 and 19.6%, respectively, greater in RT than NR. For vegetation characteristics, the results exhibited little changes in plant species richness (S = 8 and 7 for RT and NR, respectively), while the stand density and basal area enhancement were recorded for RT. The increase in plant species population and improvement in their regeneration status in RT was observed in comparison to NR in the study area. The density-diameter distribution showed that post-restoration, number of individuals in RT increased substantially in lower (10–25 cm), medium (35–55 cm), and highest (>65 cm) diameter classes with the cumulative percentage increase of 12.2, 44.1 and 12.6, respectively in comparison to the diameter classes 25–35 cm and 55–65 cm which recorded the decrease of 9.8% and 18.3%, respectively. In the case of NR, the results exhibited an alarming trend with a substantial decrease of individuals in lower diameter classes, namely, 15–35 cm (−19.7%), and 55–65 cm (−7.6%), thereby, suggesting the higher vulnerability to degradation than RT. The results of biomass and carbon contents indicated the overall biomass (aboveground and belowground) increase of 97.67 Mg ha−1 in RT and a reduction of 17.46 Mg ha−1 in NR, indicating the restoration added enough biomass to cause measurable changes. The results are evidence of the successful passive restoration efforts via fencing on soil and community characteristics across temperate coniferous forests. Restoring the vulnerable coniferous forests in the Himalayas is recommended to regain their vitality and vigour along with safeguarding the local livelihood options.