Monitoring of large-scale forest restoration: Evidence of vegetation recovery and reversing chronic ecosystem degradation in the mountain region of Pakistan

Global ecosystem restoration efforts are aimed at climate change mitigation. In response to the challenge of global warming and supporting local adaptation, the Billion Tree Tsunami Afforestation Program (BTAP) was launched in 2014 to restore depleted forest ecosystems by extensive afforestation and/or reforestation in the Khyber Pakhtunkhwa Province of Pakistan. Under the BTAP, afforestation of all categories was carried out in an area of 300,000 ha, and 160 million plants were distributed under Farm Forestry and 4509 enclosures were established for Assisting Natural Regeneration (ANR) with the help of the local community. The present study evaluated historic deforestation trends using bi-temporal (1990-2010) change analysis and the performance of recent forest ecosystem restoration efforts based on time series analysis of stallite images. A total of 226 afforestation sites of the BTAP - Phase I were examined to determine the vegetation growth and evidence of ecosystem restoration efforts by regression and trend analysis of the annual normalized difference vegetation index (NDVI) composites from 2014 to 2021. The forest plantation and protected natural regeneration performance across the three key forest management regions of the Southern, Malakand and Northern zones remained variable, with growth values of 29%, 47% and 24%, respectively. The results suggest that the three forest regions lost 3.2% of the forest between 1990 and 2010. While accounting for most conservative figures validated from satellite data, the BTAP interventions during 2014-2018 improved the overall forest cover from 14.5% to 16.5% in these regions. The framework developed in this study and the derived results can help to formulate an evidence-based assessment of indicators for ecological restoration and nature-based solutions.