An international research team has identified a combined area larger than Mexico with the potential for natural forest regeneration.
Led by Dr Brooke Williams, a conservation ecologist in the University of Queensland School of Biology and Environmental Science, and Dr Hawthorne Beyer, Head of Geospatial Science at carbon removal start-up Mombak, the study found that the current biophysical conditions of more than 215 million hectares could support the natural regeneration of tropical forest.
Forest restoration is a key strategy needed to meet nature-based sustainable development goals.
The identified area could sequester 23.4 gigatonnes of carbon over 30 years.
Williams said, “We need broad scale forest restoration to mitigate the biodiversity and climate crises.”
“Tree planting in degraded landscapes can be costly but by leveraging natural regeneration techniques, nations can meet their restoration goals cost effectively.”
Of the model’s total estimated potential, 98 million hectares were identified in the Neotropics, 90 million in the Indomalayan tropics, and 25.5 million in the Afrotropics.
The study highlights that five countries – Brazil, Indonesia, China, Mexico and Colombia – account for 52 per cent of the regeneration potential, underscoring the need for targeted restoration efforts.
University of Queensland Professor Jonathan Rhodes, a co-author of the study, explained these countries with high potential for national regeneration also represent important social and economic opportunities.
He said, “It is important that the implications for local people are considered to ensure that they also benefit from restoration activities.”
Dr Renato Crouzeilles, Director of Science at Mombak, said that atural regeneration techniques often result in more biodiverse forests when compared to tree planting. He said, “Where ecological conditions are such that forests can grow back on their own or with low-cost assistance, natural regeneration can be more effective than full tree-planting in terms of biodiversity outcomes.”
Tropical forested regions are particularly important due to their unparalleled biodiversity, rapid growth rates and because large areas have already been cleared and degraded.
Forest consultant, Andrew Heald, who was not part of the research, said, “We need to be a little cautious with these high level studies and maps. Every project and location will have a unique set of factors & circumstances, 10 miles away or in 10 years time those circumstances and factors will be different.
“Fundamentally forestry & forest restoration isn’t really about trees, it is about people.
“In my opinion for a successful project, whether the trees have regrown from local seed or from planted seedlings, is less important than involvement of local communities, accountable local governance and ensuring that the main drivers of deforestation are being addressed.”
The research is based on a dataset created by a team of international experts, including Associate Professor Matthew Fagan from the University of Maryland, Baltimore County, who analysed historical natural regrowth patches and categorised forest regrowth across tropical regions.
Fagan said, “In a previous study, we used satellite images to identify millions of small areas where tree cover increased over time.
“We then used machine learning to exclude the areas planted by humans, focusing on natural regrowth. Those natural patches were the input data for this novel study, the first to predict where future forest regrowth will occur, given observed past regrowth.”
Dr Starry Sprenkle-Hyppolite, Restoration Science Senior Director at Conservation International, highlighted the model’s value for implementing targeted, scalable and cost-effective restoration strategies.
She said, “We are already using this dataset to explore and ground truth ‘hotspots’ for natural climate solutions based on assisted natural regeneration, working with local communities and land managers who may be interested in allowing some of the forest to recover on their land. This strategy can help encourage more investments in nature so that forests stay healthy and continue to provide the food, water and economic opportunity that humanity needs to survive.”
To support and advance tropical forest restoration, the authors have made the dataset publicly available and free to use. Williams said, “As we are increasingly faced with the impacts of climate change, the team urges governments to recognise the importance of leveraging natural regeneration potential as a powerful nature-based solution.
“We must restore vast areas of these important ecosystems that deliver multiple benefits to nature and people.”
Read the full paper, The global potential for natural regeneration in deforested tropical regions