Ten golden rules for reforestation

Tree planting is becoming an important part of climate change mitigation strategies, however the wrong trees in the wrong places can do more harm than good

Urgent solutions to global climate change are needed. Ambitious tree‐planting initiatives, many already underway, aim to sequester enormous quantities of carbon to partly compensate for CO₂ emissions, which are a major cause of rising global temperatures. However, tree planting that is poorly planned and executed could actually increase CO₂ emissions and have long‐term, deleterious impacts on biodiversity, landscapes and livelihoods.

Building on current evidence and their own experiences, a team of international scientists propose 10 golden rules to guide tree planting.

1. Protect existing forest first: Before planning reforestation, always look for ways to protect existing forests, including old‐ and second‐growth, degraded and planted forests.
2. Work together: Involve all stakeholders and make local people integral to the project.
3. Aim to maximize biodiversity recovery to meet multiple goals: Restoring biodiversity facilitates other objectives—carbon sequestration, ecosystem services and socio‐economic benefits.
4. Select appropriate areas for reforestation: Avoid previously non‐forested lands, connect or expand existing forest, and be aware of displacing activities that will cause deforestation elsewhere.
5. Use natural regeneration wherever possible: Natural regeneration can be cheaper and more effective than tree planting where site and landscape conditions are suitable.
6. Select species to maximize biodiversity: Plant a mix of species, prioritize natives, favour mutualistic interactions and exclude invasive species.
7. Use resilient plant material: Obtain seeds or seedlings with appropriate genetic variability and provenance to maximize population resilience.
8. Plan ahead for infrastructure, capacity and seed supply: From seed collection to tree planting, develop the required infrastructure, capacity and seed supply system well in advance, if not available externally. Always follow seed quality standards.
9. Learn by doing: Base restoration interventions on the best ecological evidence and indigenous knowledge. Perform trials prior to applying techniques on a large scale. Monitor appropriate success indicators and use results for adaptive management.
10. Make it pay: Develop diverse, sustainable income streams for a range of stakeholders, including carbon credits, NTFPs, ecotourism and marketable watershed services.

Reforestation is more complex than is often initially thought. There is no universal, easy solution to a successful initiative given the extraordinary diversity of species, forest types, sites, and cultural and economic environments. In many cases where livelihoods depend upon altered landscapes, restoration goals can only be achieved through creating a mosaic of land uses at the landscape level and by engaging with society at large.