Deforestation 101: What It Is, Why It Happens & Why It's So Harmful

When you hear about the massive tree-planting efforts happening around the world, it's easy to forget just how harmful deforestation can be. Who cares if we lose a tree if we go on to plant one, or even two, in its place, right? Wrong! This mentality doesn't account for the major threat that deforestation plays to human, animal, and ecosystem health.

Here's an overview of why deforestation is so harmful, what can be done about it, and why it happens in the first place.

The drivers of deforestation will differ depending on where in the world you look. Terrana explains that while many forests in the Congo Basin are being cut for roads and railways, for example, forests in Southeast Asia are largely cleared to make way for palm oil production.

It's difficult to keep people from cutting down forests since they typically make money doing so. Take the Amazon rainforest as an example: Liana Anderson, Ph.D., a biologist who studies climate extremes in the region, explains that the deforestation rates in the Amazon rose dramatically at the turn of the century as more farmers cleared forest land to grow and feed cattle that they then went on to sell.

By 2005, a suite of policies was in place to protect the forest, successfully reducing deforestation by rates of up to 37% per year. However, Anderson notes, "We failed to enforce these laws. We failed dramatically." These environmental policies had steadily been weakened in the years leading up to the massive 2019 fires in the region—most of which were intentionally set by farmers and loggers to clear land for growing crops and other commodities. Anderson says that deforestation continues to be a huge concern in the Amazon, exacerbated by practices like land grabbing (private companies claiming ownership of public land for development).

Forestlands tend to be very fertile, making them prime spots for growing. Clearing them can cause economic gain in the short term, but it comes at a dangerous long-term cost.

Clearly, there are no easy solutions here. To solve this problem, we'll need to fundamentally reimagine the way we value land. "On the whole," Terrana says of the issue, "the way we produce and consume globally isn't sustainable at a large scale." Here's a look at some of the ways that deforestation negatively affects people and communities around the world:

Around 1.6 billion people around the world depend on forests for their livelihoods. As WWF explores in its new report, The Vitality of Forests, deforestation can harm these people by reducing their access to food, shelter, shade, and plant medicine.

Indigenous populations, who have lived in a reciprocal relationship with the forest for hundreds of years, are often hit hardest. "Indigenous peoples are quite literally on the front lines of some of this deforestation, and they're not the ones who are perpetuating it," Terrana adds.

Forests—particularly primary forests—are an essential tool for mitigating climate change. As trees grow older, they absorb more and more carbon from the atmosphere and store it in their trunks and root systems. Once they're cut down, that carbon gets released back into the atmosphere, where it contributes to global warming1. For this reason, the UN has declared that "Stopping deforestation and restoring damaged forests, together with other land-based actions, could provide up to 30% of the climate solution."

And carbon isn't the only thing that trees can gobble up as they grow: Forests help remove other pollutants2 from our air and water too.

Deforestation also displaces some of our planet's most spectacular wildlife. Deforestation hot spot Sumatra, for example, is "the last place in the world where you have orangutans, tigers, and elephants all living together," says Terrana. Destroying primary forest habitats like those in Sumatra threatens the survival of these species and many others. And since everything in nature is dependent on one another, disrupting one species will ultimately disrupt everything around it.

Anderson calls the Amazon one of the most "precious resources that we have in Brazil"—not just because of its beauty but because of its ability to regulate temperature and humidity. The rainforest promotes rainfall throughout South America. Research shows that deforestation (paired with climate change) now seems to be contributing to historic droughts in regions like São Paulo. "My view is that the amount of deforestation that we have so far is already affecting the hydrological cycle," Anderson says.

If trees provide shade and water, it makes sense that chopping them down would lead to hot, dry conditions—the type that are ideal for wildfires. Uncontrolled wildfires are obviously harmful to forest communities, but their danger spreads even further than that. "It has been suggested that the fires associated with deforestation in the Amazon are responsible for over 2,000 deaths in South America per year," Anderson explains, due to increased exposure to air pollution.

Think back to the last time you visited an established, undisturbed forest. The smell of the bark and damp earth, the feel of the cool air on your skin, the sounds of the canopy rustling overhead likely left you feeling calm and invigorated, right? Spending time in the woods is a treat for the senses (and potentially our immune strength) that I, for one, can't imagine losing.

And while you can plant new trees to take on some of the qualities of ancient ones, it will take decades (if not centuries) for these saplings to get established. That's because when we destroy a tree, we also destroy the intricate underground fungal networks that the tree uses to send resources back and forth to its neighbors. We're learning more about these networks (nicknamed, the "woodwide web") all the time, and ongoing research reveals just how fascinating and fragile they are.

A team out of the University of British Columbia, spearheaded by Suzanne Simard, Ph.D., is even suggesting that the network's oldest trees take on maternal qualities over time: They transfer nutrients to young trees in need and protect their kin from threats. These are the mother of all trees, and they're well worth protecting.

As the Amazon example proves, reducing deforestation will require governments, corporations, and local communities to come together and agree on binding policy changes. However, Terrana notes, there are ways that individuals like you and me can use our purchasing and political power to help move the process along. Here are a few:

We're losing far too much valuable forest land to deforestation every day. This is one environmental problem with no easy solution, but we can all play a part in slowing it by making smart purchasing decisions, supporting groups doing good work, and continuing learning and talking about the issue all the time—not just when it's in the news.