Let’s talk the right trees

Some time ago, internet users criticized a payment app that made good on its promise to “plant trees.” Years ago, the same effort reforested the Ipo Dam watershed using seedlings of native trees that grew in the area. This round, the initiative apparently resulted in a coconut plantation.

Some internet users questioned the project, while others contended that any kind of tree is better than none for a desperate, deforested country.

However: Not all trees are created equal. Some are better adapted to our climate, soil, and growing conditions. They absorb and metabolize carbon dioxide and other gases efficiently without outcompeting other species in the area.

The best examples of such trees include native species, or those naturally found over a wide geographical range in our region (such as narra) as well as endemic species, or those naturally found in specific places (such as Philippine teak).

Other trees, despite providing good shade, are actually harmful in the long term. These include invasive species accidentally brought to our islands, or planted by well-meaning individuals who did no prior planning or research.

Yes, some invasive species have already adapted to our climate and changing weather patterns, taken to our soil and welcomed wildlife, provided shade. Sadly, most nonindigenous species don’t always play nice.

Mahogany is one such species. It is popular in local greening programs because it grows fast, anywhere. This is because mahogany changes the soil to suit its growth requirements. These changes, however, also prevent other organisms from living alongside mahogany, including soil bacteria that would benefit other plants and other trees that would allow insects and birds to thrive.

This dangerous outcompeting is most evident in Bilar, Bohol’s mahogany forest, which was planted in response to excessive slash-and-burn farming. The forest is shady and quiet, and with good reason: Many birds and insects don’t live there and have sought forests elsewhere for their habitat. Birds are no mean species: They carry the seeds that can help more trees and plants grow and thrive across the archipelago.

While mahogany spreads, narra, kamagong, and the almaciga tree of the Sierra Madres are now endangered.

Coconut plantations are no better. Research by Hillary Young and colleagues (Proceedings of the National Academy of Sciences, 2010) shows that bird species that are important to enriching the soil also don’t nest in coconut trees; as a result, the soils around coconut plantations are also low in nutrients and can’t sustain other plant species. Research on Mexico’s Yucatan, from a variety of researchers, also shows that coconut plantations threaten mangroves that serve as natural barriers to flooding.

A coconut plantation is a monoculture, or a plantation of only a single species. Monocultures require larger amounts of resources to start and maintain, leading to higher costs of irrigation, pesticide use, and fertilizers. Having only a single species densely packed into one area also makes the plantation a prime target for pests. When one species gets a disease, the entire plantation is in danger and can be much more easily wiped out than a plantation of diverse crops.

Yes, a plantation is profitable, but having one shouldn’t lead to ecosystem damage. And yes, a coconut plantation can help a community, but it shouldn’t be the only solution for reforestation. We aren’t killing two birds with one stone by calling a plantation a forest.

Resurrecting our biodiversity isn’t as simple as planting trees. It means targeting the many players in our multiple ecosystems: the soil that needs to stay rich for future generations of plants, the water that has to be free from contaminants, the air that has to be free from pollutants, the plants, trees, birds, and beasts that play on the delicate balance of death and life.

Planting trees is good, but it has to be planned carefully. We need to plant multiple native species in the right areas at the right time so that we have the right growing conditions for the trees to truly take root and thrive, and so that we cause the least disruption to our already fragile ecosystem.

Planting trees is only the beginning. Local communities and scientists have to work together to maintain these trees, all while engaging in sustainable, environment-supporting, and safe livelihoods.

Helping the environment doesn’t mean “just do anything now,” and it certainly doesn’t mean “let’s do as we please because science changes anyway.” Scientists debate about their findings, but we always need to make policy decisions based on the best research at that point in time. The systematic approach to solving problems has not changed.

Research shows that we need sustainable forest cover. Our strategies, therefore, have to be nuanced. There’s no such thing as “it’s better than nothing” when the planted somethings are actually lethal in the long term while appearing beneficial in the short term.

iponcedeleon@ateneo.edu