A new study, led by the Forest Ecology and Conservation group, has produced the first large-scale, high-resolution map of how quickly tropical forests recover carbon and structure when left to regrow naturally on former pastureland.
The team used repeated airborne laser scans (lidar) across Brazil's Atlantic Forest to track precise changes in the forest structure over a 6-year period. The findings show that passive restoration – simply allowing nature to take its course – can be a highly effective and verifiable tool for climate mitigation.
Why it matters for carbon markets
The Atlantic Forest is one of the world’s most degraded biodiversity hotspots, having been extensively cleared for cropland, cattle ranching, and short-rotation eucalyptus plantations. In response to this widespread degradation, Brazilian law requires landowners to restore at least 20 percent of their land to native vegetation.
While carbon credit projects are helping to meet this requirement by financing restoration and expanding the area of young forest across the region, lead author Felipe Begliomini notes that traditional carbon-accounting methods have often proven insufficient for verifying restoration outcomes at scale.
Begliomini warns that insufficient data "can lead to inaccurate estimates that erode investor confidence in climate mitigation efforts". The team's framework, published in the ISPRS Journal of Photogrammetry and Remote Sensing, is designed to address this challenge by giving restoration projects and carbon-credit certifiers a repeatable, high-resolution tool for tracking real forest recovery over time.
Six years of lidar reveal rapid recovery
The study analysed two lidar surveys flown in 2012 and 2018 over 475 eucalyptus farms in Brazil's Paraíba Valley, covering 69 square kilometres of land undergoing passive restoration.
To ensure accuracy, the team developed a new correction method to remove sensor-related errors, such as terrain-model offsets and differences in laser pulse density. These errors can otherwise mask real forest growth in repeat lidar surveys.
“This work shows how multi-temporal airborne laser scanning can deliver rapid, large-scale, and reliable data on forest structure change, enabling accurate carbon accounting and restoration forecasts. Our findings can directly support the planning and scaling of tropical forest restoration projects,” Begliomini says.
A standout carbon accumulation rate
The study found that young secondary forests in the region accumulated carbon at 2.03 megagrams per hectare per year. This is among the highest rates reported in any multi-temporal lidar study and roughly double the rate typically reported for other temperate and old-growth tropical biomes.
Overall, restoration across the 69 square kilometre study area generated a net carbon gain of 45,000 megagrams of CO2 per year. This is equivalent to offsetting the annual carbon footprint of 20,000 people.
Restoring all legally required pasture in the region could sequester roughly 14.7 million megagrams of CO2 over 30 years across 770 square kilometres.
Broader implications for carbon markets
Professor David Coomes, Head of the Forest Ecology and Conservation group, and senior author on the paper, emphasises that the integrity of carbon markets for forest restoration depends on such precise structural change measurements over large scales.
"Robust, standardised monitoring methodologies are essential to ensure accurate assessments, restore credibility, and support greater investment in natural climate solutions," he explains.
The paper argues that simulated carbon uptake rates in the region, while below broader Neotropical and IPCC estimates, were 45 percent above the regional mean drawn from a global chronosequence dataset – underscoring the importance of locally calibrated models for accurate carbon accounting.
Reference: Felipe N. Begliomini et al. ‘Tracking forest carbon and growth in large-scale passive restoration using multi-temporal airborne lidar.’ ISPRS Journal of Photogrammetry and Remote Sensing, DOI: 10.1016/j.isprsjprs.2026.07.013.
Image: A view of the fragmented Atlantic Forest landscape, showing a mosaic of different land uses and forest patches at varying stages of succession. The landscape illustrates the diverse land-use patterns and opportunities for forest restoration across the region. Credit: Felipe Begliomini.