More than half of all tropical forests are degraded by human impacts, leaving them threatened with conversion to agricultural plantations and risking substantial biodiversity and carbon losses. Restoration could accelerate recovery of aboveground carbon density (ACD), but adoption of restoration is constrained by cost and uncertainties over effectiveness. We report a long-term comparison of ACD recovery rates between naturally regenerating and actively restored logged tropical forests. Restoration enhanced decadal ACD recovery by more than 50%, from 2.9 to 4.4 megagrams per hectare per year. This magnitude of response, coupled with modal values of restoration costs globally, would require higher carbon prices to justify investment in restoration. However, carbon prices required to fulfill the 2016 Paris climate agreement [$40 to $80 (USD) per tonne carbon dioxide equivalent] would provide an economic justification for tropical forest restoration.
Bibliographical noteAcknowledgements: We thank the Sabah Biodiversity Council and the Danum Valley Management Committee for permission to conduct this work. INFAPRO field data were obtained by research assistants at Yayasan Sabah’s and Face the Future’s joint large-scale forest rehabilitation project INFAPRO. We acknowledge the assistance and support from the South East Asia Rainforest Research Partnership (SEARRP) and Sabah Forestry. We also acknowledge John Tay for assistance and advice for the original set-up of the project. We are grateful to Jake Alexander, Natalia Ocampo-Peñuela, Elaine Watts and Jules Bailey from mosaic media for help with graphics and cartography. Comments from four anonymous reviewers and editors greatly improved previous versions of the manuscript. Funding: Field data were acquired for the EU funded INDFORSUS project (ER-BIC18T960102) to GMF and from projects funded by the Carnegie Trust for the Universities of Scotland (Ref. 50076) to MEJC and DFRPB and the DfID / NERC Programme ‘Understanding the impact of the current El Nino event’ (NE/P004806/1) to MEJC, DFRPB, DSB, GMF, GMFvdH. Airborne carbon mapping, processing and analysis were funded by the UN Development Programme GEF, Avatar Alliance Foundation, Roundtable on Sustainable Palm Oil, Worldwide Fund for Nature, Morgan Family Foundation, and the Rainforest Trust to GA, GR.
- ABOVEGROUND BIOMASS
- ALLOMETRIC MODELS
- TREE DIVERSITY