The Canopy Project

5 Reasons We Need Trees for a Healthy Planet

Since the start of human civilization, we’ve cleared 46% of trees globally. And today, with our sprawling urban areas and wide open fields, it’s tough to envision what a truly wooded world looked like. 

In 2022 alone, we lost 22.8 million hectares of tree cover to deforestation, logging and fires — equivalent to a soccer field of trees every six seconds. Climate change doesn’t help matters: New findings suggest that deforestation, alongside rising temperatures, is transforming what’s left of our forests, keeping trees smaller and younger.

To ensure a safe, healthy future, we must restore these forest habitats. Here are five reasons we need trees. 

1. Trees purify our air and combat climate change 

Forests are carbon sinks that help slow climate change by removing carbon from the atmosphere and storing it in trunks and soil. And old-growth trees — trees that have reached old age without major human disturbances like logging — hold much larger amounts of carbon and harmful pollutants than their younger counterparts.

Today, trees absorb 30% of global emissions every year. And when we burn them or cut them down, all of that pollution gets released into the air. A recent study estimated that from 2010 and 2050, global forest loss will result in 3.5 to 4.2 billion metric tons of greenhouse gasses entering the atmosphere each year. Even small amounts of air pollution contribute to a plethora of health issues that affect society unevenly.

2. Trees provide housing to millions of species that protect us from disease

50 percent of all plants and animals on Earth live in rainforests. We now know that almost two million species worldwide are at risk of extinction -– nearly double the number we had estimated just five years ago.  

A quarter of our medicine comes from plants found in the rainforest, and if you add the species in coral reefs, species make up 40–50 percent of our pharmaceuticals. As we continue to encroach on and destroy forest habitats, however, we lose these valuable species and create bigger threats. 

Already, three out of every four new infectious diseases in people come from animals, and this number has only increased as we’ve moved into wildlife habitats and increased contact. But studies show that high levels of biodiversity actually have a “dilution effect” on disease within hosts, making diseases less likely to jump to humans. 

In other words, protecting forest habitats and the species that live within them could prevent the next pandemic.  

3. Trees cool our streets and cities

2023 was the hottest year on record. 2024 looks set to be even hotter

Trees, though, cool the Earth by blocking sunlight and providing shade — air temperature under trees can be 25°F cooler than surrounding air. They can also reduce energy use for cooling and heating. The Department of Energy states that planting trees around your house can reduce solar heat gain from windows and roofs, thus reducing costs for air conditioning. 

Trees also help control climate through evapotranspiration — a process where water is drawn up through the soil by the roots and evaporates from the leaves. The surrounding air cools as the water transforms to vapor. One tree can transpire 11,000 gallons of water into the atmosphere per year.To combat the heating effects of concrete in cities, studies suggest we need at least 40 percent canopy coverage. With over half of the world’s population living in cities — notoriously hotter because of concrete, poorer air quality, limited shade and green space, buildings — we must try all we can to beat the heat.

4. Trees protect against floods and water pollution

Mature trees protect communities against flash floods and landslides by stabilizing soil and absorbing water — between 1,500 and 2,000 liters of water per year. On the other root (hah), a lack of trees can lead to increased runoff and floods

Tree roots also filter harmful chemicals and pollutants from storm runoff that ends up in lakes, streams and rivers. Forests provide drinking water to more than 150 million people in the United States, according to the U.S. Forest Service. 

Or, put simply: more trees = cleaner water.

5. Trees ease the mind during stressful times 

If we continue to destroy the environment, we’ll be living in very stressful conditions: droughts, massive storms, pandemics, floods. But trees have a double effect on society: fighting climate change while relieving stress.

Trees in rural and especially urban areas benefit our mental and physical wellbeing. Studies show that urban trees result in better health outcomes for local communities, including improved cardiovascular function, more thermal comfort, and reduced anxiety.  

Spending just a few minutes outdoors can reduce blood pressure, relieve stress and build a stronger immune system. But there are even benefits from viewing nature from a window, like increased job satisfaction

It’s going to take more than reforestation 

Investing in reforestation (like through EARTHDAY.ORG’s The Canopy Project) can certainly help slow climate change, and provide many benefits to both humans and the environment in the short and long term. Planting forests is a critically important way to help restore our Earth

But while planting trees is important, we must also address the underlying issues of air and water pollution, the burning of fossil fuels, and the impact of mass consumption which are all part of the climate change problem. In addition to championing trees, please sign our Plastic Petition to force the governments of the world to fight plastic production and pollution. Think about buying less and rejecting Fast Fashion. Work your Green Muscle Memory so that you make Earth-friendly decisions every single day.