bringing the forest back: restoration priorities in Colombia

Aim: Colombia has committed to ambitious forest restoration targets which include a one million ha Bonn Challenge commitment and 6.47 - 8.31 million ha (rehabilitation and restoration, respectively) under the National Restoration Plan. Determining where and how to implement programs to achieve these targets remains a significant challenge.

Location: Colombia

Methods: We adopt a multi-objective optimisation framework for restoration planning and apply it to Colombia. We explore cost-effective solutions that leverage the potential for assisted natural regeneration benefits while accounting for opportunity and establishment costs of restoration and maximising biodiversity conservation and climate change mitigation benefits. We explore four politically relevant restoration areal targets (one, six, 6.47 and 8.31 million ha) and identify minimum cost, and suites of maximum benefit and cost-effective solutions.

Results: We identify solutions that simultaneously perform well across biodiversity and carbon objectives, despite trade-offs between these objectives. We find that cost-effective solutions can achieve on average 91.1%, 90.8%, 90.5%, and 90.1% of maximum carbon benefit and 100% of the maximum biodiversity benefit while significantly reducing costs. On average, the maximum benefit solutions reduce the cost by 16.9%, 30.2%, 31.1%, and 34.4% when considering the one, six, 6.47 and 8.31 million ha restoration targets respectively.

Main conclusions: Colombia has committed to bold restoration and conservation targets, such as those under the new 2030 Convention on Biological Diversity Global Biodiversity Framework. Strategic forest restoration planning will play an important role in achieving Colombia’s climate mitigation goals. We provide quantitative evidence to inform planning for environmentally and economically sensible restoration policy and practice in the country. Our framework and results can help guide Colombia towards meeting its ambitious forest restoration targets cost-effectively.

Methods
We used spatial prioritisation, the process of using computational tools for the informed spatial allocation of actions or placement land uses, to achieve an objective of restoring forest to maximise biodiversity and carbon sequestration benefits within selected priorities, while considering establishment and opportunity cost. Tree planting and extensive site preparation are popular restoration strategies and can be effective, but implementation can be prohibitively expensive for some sites or at large scales. Where ecological conditions are such that forests can grow back on their own or with low-cost assistance, natural regeneration methods can be less costly. To leverage these potential costs our establishment cost estimates account for the potential for natural regeneration by adjusting values relative to a spatially explicit random forest model.