Beyond tree planting

The case for natural regeneration of forests
Juan Carlos Huayllapuma Cruz/CIFOR.

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When most people think of forest restoration, they think of planting trees.

But at the scales needed to meet ambitious global land restoration targets, the costs involved are prohibitive – from buying millions of seedlings to paying people to plant and maintain them. But there is a powerful, cost-effective alternative: nature itself.

In a new paper, Manuel Guariguata from the Center for International Forestry Research (CIFOR) and Robin Chazdon from the University of Connecticut argue that harnessing forests’ natural ability to repair and regrow is essential if countries hope to meet achieve restoration goals like the Bonn Challenge and the 20×20 Initiative.

“Especially for those countries that have pledged several million hectares, like Mexico, it would be unrealistic – or at least very costly – to do this with tree planting alone,” says Guariguata.

So what can be done instead? Chazdon points to the example of the Guanacaste region of Costa Rica. By the late 1970s, much of the area’s dry forests had been cut down, as farmers cleared pastures and rode the ‘cattle boom’ of high beef prices. When the international market suddenly slumped around 1980, smallholders on the more marginal lands could no longer make ends meet.

Huge numbers simply walked off their farms – and the forest crept back to claim them.

Fast-growing woody vegetation established itself first, tree seedlings and shrubs colonising the disturbed soil. Soon they shaded out the grass, and attracted birds and bats to roost, eat berries and disperse seeds. As each year passed, new plants and animals arrived – and bit-by-bit, the forest returned.

In Costa Rica’s case, though economic changes were the main impetus for the regeneration, political changes – including restrictions on forest clearing and a significant payments for environmental services (PES) program – helped ensure the new forests’ survival.

“The area now has close to 50 percent forest cover and is regaining a lot of wildlife in these forest patches,” says Chazdon.


Despite such successes, natural regeneration has so far been largely overlooked in reforestation planning. Chazdon calls regenerating areas ‘orphaned lands’ because they have fallen through the cracks.

“Conservation organisations have orphaned them because they haven’t seen some of this young regrowth as something worthy of conservation; agriculture has orphaned them because they’re obviously regrowing on land that isn’t deemed very useful for agriculture, and forestry has orphaned them because they’d much rather see neat little rows of trees than this unpredictable regeneration with many non-commercial species,” she says. “They haven’t had a place – so we are trying to give them a much more central place.”

Part of the problem is a very widespread perception of regenerating forest as wasteland.

In Costa Rica, Chazdon says, farmers sometimes remove what they see as scraggly vegetation “because they want to do reforestation, and they have no idea that they’re clearing some really valuable tree species that have just gotten established there – that no one had to plant.”

There are also strong social pressures working against natural regeneration.

“In many tropical countries, fallow land can make a farmer look bad, conveying a message that is not being worked,” Guariguata says.

“We’re not saying that all unused land should be left for nature to take over, no – we need to create incentives for these regenerating forests to remain so, and to compensate landowners for not using that land for agricultural activities.”

That doesn’t necessarily mean outright payments – although these can work in the short term, Chazdon and Guariguata don’t see them as economically sustainable over long periods. Value from secondary forests could be created in a number of ways, they say – enhancing and selectively harvesting commercial species from the secondary forest, or securing premium pricing for non-timber forest products.

Incentives can also be social, Chazdon says.

“Farmers could become stewards of natural regeneration – there has to be some status associated with it. There could be prizes, clubs – social benefits and acceptance into certain programs if they do this.”

“It won’t happen overnight. Cultural changes are always slow, but I’ve seen attitudes change in Costa Rica in the 30 years I’ve been working there,” she says.

“People are very proud of their secondary forests. So they just need the right kind of social environment, encouragement and education to see how they can play an active role in this whole process.”

At the national level, reforestation programs are usually run by forestry departments, where people are experts in growing a few species of plantation trees – so that tends to be their go-to solution. Tree planting can seem like a ‘quick fix’, making politicians look like they’re doing something – and there are economic benefits to planting predictable, commercial tree species.

But Chazdon and Guariguata argue that officials can learn to identify areas that lend themselves to natural regeneration, and therefore focus tree-planting funding on other places where it is really needed.

New research by Chazdon and her collaborators in Brazil has found it is possible to map the probability of natural regeneration using landscape and other climate information – rainfall, slope, elevation, proximity to forest fragments and rivers.

Guariguata says more effort needs to be invested in training and decision-making tools to help foresters, ecologists and natural resource managers identify “the best sites to let nature take its course.”

“There are sophisticated tools but they’re not yet widely available or widely known in most developing countries where the need is the most acute. Maps that show only the extent of site degradation are quite common as decision-making frameworks, but this kind of information is just part of the picture – these tools need to also incorporate both biophysical and socioeconomic data.”

The benefits of this approach are massive, the scientists say – and not just because countries will save money. They’ll also provide a much bigger boost to biodiversity than the kinds of monoculture tree crops often relied upon in reforestation programs. And that will enhance resilience, Chazdon says.

“Natural regeneration is not a panacea, it is a complement. But it is one that has been largely overlooked and underutilised. The potential is enormous.”

Manuel Guariguata, CIFOR scientist

“When climate change and other kinds of impacts start kicking in, having the heterogeneity and more local varieties of plants is going to be very important – I see it as much less risky than large-scale monoculture plantations.”

“We have to think long term, and so far we haven’t been doing that – that’s one reason degraded land is so prevalent around the world.”

“Natural regeneration is not a panacea, it is a complement,” Guariguata adds. “But it is one that has been largely overlooked and underutilised. The potential is enormous.”

For more information on this topic, please contact Manuel Guariguata at
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