Where in the World is There Potential for Tropical-Forest Regeneration?
The identification of regions where forests can recover naturally and effectively with minimal intervention is crucial for large-scale restoration efforts. While tree planting and intensive site preparation are common strategies, they often come with high costs that are prohibitive for many low- and middle-income countries. Moreover, these methods do not always facilitate the effective recovery of native biodiversity. In areas where ecological conditions allow, forests may regenerate naturally at a lower cost and with greater long-term success and biodiversity benefits compared to artificial plantations. However, the restoration community currently lacks an effective tool for predicting the regions where natural regeneration is most viable and beneficial.
A recent study employed modeling techniques to identify potential sites for tropical-forest regeneration by analyzing a variety of biophysical and socio-economic factors. Using data from 2000 to 2016 with a 30-meter resolution time series on tree cover from Global Forest Watch, the study utilized a machine-learning algorithm—known as random forests—to predict where natural regeneration might likely occur by 2030.
The findings revealed that approximately 215 million hectares of tropical forest worldwide, comprising areas in the neotropics, Indomalayan tropics, and Afrotropics, possess the biophysical conditions necessary for natural regeneration by 2030. Notably, Brazil, Indonesia, China, Mexico, and Colombia account for around 52% of the global potential for natural regeneration. Additionally, 29 other countries each have regions exceeding 1 million hectares that could naturally rejuvenate.
While some identified areas are capable of regenerating without direct human intervention, assisted natural-regeneration methods could enhance regrowth rates. This involves implementing management actions such as excluding grazing animals, controlling invasive species, and preventing agricultural expansion in these areas.
It is pertinent to mention that the analysis does not prescribe specific policy or management strategies to promote natural regeneration. Such decisions should be based on regional conditions and restoration goals set by local stakeholders.
Extensive forest restoration is imperative for combating climate change. Global policy platforms have set ambitious targets to significantly expand natural ecosystems by 2050. For example, the Bonn Challenge aims to restore 350 million hectares by 2030, while the Global Biodiversity Framework’s second target stipulates that 30% of all degraded ecosystems should be restored by 2030. The model developed in this study aims to support these initiatives in a cost-effective manner.
Importantly, the study does not specify exact sites for restoration or take into account factors such as feasibility, socio-economic constraints, or benefits beyond carbon sequestration, including biodiversity conservation objectives. Instead, its high-resolution maps of natural regeneration potential are designed to be used as a component of broader decision-making processes for conservation and land-use planning. The biophysical potential for natural regeneration is but one of many factors to consider when making restoration-related decisions.
Natural forest regeneration offers an opportunity for cost-effective restoration on a large scale, significantly contributing to climate-change mitigation efforts by enhancing carbon sequestration and working towards net-zero carbon emissions by mid-century. Moreover, it brings substantial additional benefits such as conserving biodiversity, regulating water resources, reducing erosion, and increasing ecological resilience. These maps could therefore serve the diverse, interconnected environmental agendas at both national and international levels.
The focus of this study is on the potential for tropical forest regeneration as a response to the need for cost-effective restoration solutions, particularly for under-resourced nations compared to those in temperate zones, where natural regeneration has demonstrated positive outcomes. Tropical forests are vital due to their unmatched biodiversity, significant economic, cultural, and recreational services, as well as their rapid growth rates compared to other forest types, compounded by the extensive degradation and clearing they have experienced.
This research is a collaborative effort among experts in ecological restoration and conservation, aiming to offer insights and tools necessary for addressing the pressing challenges of tropical forest restoration.
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