Beyond tree planting: complementary roles of agroforestry and rainforestation in reducing tropical deforestation pressure

When we hear that the world needs to plant more trees to save the rainforests, the image that comes to mind is often a simple one: a person digging a hole, dropping in a sapling, and watching a forest grow. This impulse is well-meaning, but it hides a crucial truth. Not all trees are the same, and not all places where trees grow serve the same purpose. A forest that has stood for centuries, holding complex layers of life and storing vast amounts of carbon, is fundamentally different from a farm where trees are mixed with crops, or a patch of land where a few fast-growing species were planted to replace a degraded hillside. The challenge for the planet is not just to increase the number of trees, but to understand where they should grow, what kind they should be, and how they fit into the lives of the people who live among them. If we treat every tree-planting effort as the same solution, we risk missing the real goal: stopping the destruction of the wild forests that remain while helping people thrive on the land they already farm.

A recent review by Janny Acosta Sumilla, drawing heavily on experiences from the Philippines, cuts through this confusion by separating three distinct approaches to trees in the landscape. The first is protection, which means keeping existing, healthy forests exactly as they are. The second is natural regeneration, which involves stepping back and letting a damaged forest heal itself if the damage is not too severe. The third is active restoration, where humans plant trees to rebuild a forest on land that is too broken to recover on its own. The paper argues that we must stop treating these as interchangeable options. Instead, we need a clear hierarchy: protect what is still standing, let nature do the work where it can, and only step in with active planting when necessary. Furthermore, the review introduces a specific approach called "rainforestation," a method developed in the Philippines that uses a diverse mix of native trees to rebuild forest structure while also providing food and income for local families. This is distinct from "agroforestry," which is the practice of integrating trees into existing farms to diversify crops and improve soil.

The core finding of this work is that planting trees does not automatically stop deforestation. In fact, simply counting the number of trees planted can be misleading. A farm with a few rows of trees might look green from space, but if the farmer still needs to clear a nearby forest to survive, the pressure on the wild forest remains. The paper suggests that agroforestry and rainforestation are powerful tools, but only when used in the right places and with the right rules. Agroforestry works best on land that is already being farmed. By adding trees to these fields, farmers can grow more types of food, earn more money, and create a landscape that is more resilient to climate shocks. This can reduce the need for farmers to cut down new forest land to make a living. However, this only works if the trees actually provide a reliable income and if the farmers have secure rights to the land they are working on. Without these conditions, planting trees on farms might not change the pressure on the forest at all.

Rainforestation, on the other hand, is designed for land that has been so degraded—perhaps by mining, severe erosion, or repeated burning—that it cannot recover on its own. In these specific spots, simply waiting for nature to return is not enough. Here, the approach involves planting a wide variety of native tree species, chosen carefully to match the local environment. These trees are not just for timber; they are selected to rebuild the complex structure of a real forest, creating a canopy that shades the ground and allows new seedlings to grow. The goal is to create a forest-like ecosystem that can eventually support wildlife and store carbon, while also offering fruits and other products to the people who tend them. The review emphasizes that this is not a quick fix. It takes decades for these planted forests to develop the deep roots and rich soil of a natural forest, and it requires long-term care and management.

The paper also warns against a common trap: the idea that planting trees in one place will automatically save a forest somewhere else. This is known as "leakage." If a farmer plants trees on their own land but then decides to cut down a nearby forest because they feel they have "done their part," the net result is still a loss for the planet. Similarly, if a new tree crop becomes very profitable, it might encourage people to clear more forest to plant even more of that crop. To prevent this, the review proposes a strict set of rules. Before any tree-planting project begins, we must know exactly what was on the land before. We cannot count as a success any project that involves cutting down a natural forest or a recovering secondary forest to make room for new trees. Instead, we must focus on protecting the forests that are already there and using active planting only on the most damaged land where nature cannot recover alone.

Success also depends on the people involved. The review highlights that trees are long-term investments, and farmers will not plant them if they are not sure they will be able to harvest the wood or fruit in the future. Secure land rights are essential. If a family does not own the land or has no guarantee that they can keep the products, they are unlikely to invest the time and money needed to care for the trees. Additionally, the supply of native seeds and the knowledge of how to grow them must be available locally. The paper notes that in the Philippines, where this approach has been tested for years, the most successful projects are those where local communities have control over the process and where the trees are chosen to meet both ecological needs and family needs.

Ultimately, the paper concludes that there is no single magic bullet for saving tropical forests. The solution lies in a careful, layered strategy. We must first protect the intact forests that still exist, as they hold a unique value that cannot be recreated by planting. Where forests are damaged but still have a chance to heal, we should remove the barriers to recovery, such as grazing animals or repeated fires, and let nature take its course. Only on the most severely degraded land should we turn to active planting with native species, using methods like rainforestation to rebuild the forest structure. And on the farms that surround these forests, we should encourage agroforestry to make those farms more productive and less likely to expand into the wild. By treating these different approaches as complementary parts of a whole system, rather than as substitutes for one another, we can reduce the pressure on tropical forests while supporting the livelihoods of the people who live there. The goal is not just to have more trees, but to have the right trees in the right places, managed by people who have the security and support to care for them for generations.