The Canopy Project
6 Surprising Facts About Trees That Will Change How You See Forests
July 26, 2025
July 26 is World Mangrove Day, a moment to celebrate not just mangroves, but all the trees that protect our coastlines, clean our air, and sustain our ecosystems. Mangroves are special in the way that they serve as carbon sinks, storm buffers, and biodiversity hotspots. But even beyond the mangrove forests, trees everywhere are doing more than meets the eye. Most people know trees produce oxygen and offer shade, but that barely scratches the bark. Beneath the surface lies a hidden world of intelligence and ecological communication.
Here are six surprising facts about trees that will leave you in awe of the next one you walk past, and remind you why forests are worth protecting.
1. Trees Communicate With Each Other Through a Hidden Underground Network
If you thought the idea of talking trees belonged only in fantasy novels, think again. Trees actually communicate and share resources with one another through an underground fungal network often referred to as the “Wood Wide Web.” This network is made up of mycorrhizal fungi that connect the roots of different trees and plants.
Through these fungal threads, trees can send sugars, nitrogen, phosphorus, and even chemical warnings about environmental threats like pests or drought. Some trees, especially older and larger ones often referred to as “mother trees,” are known to support younger or weaker trees by sending them nutrients through this network.
This form of communication has major implications for forest health, resilience, and reforestation strategies. Scientists now know that logging practices that remove these elder trees can disrupt entire forest communities in unseen ways. We must love and protect our ‘mother’ trees.
2. Trees Can “Remember” Stress and Learn From It
No brain? No problem. While trees don’t have a central nervous system, recent research suggests that they can “remember” previous environmental conditions and adjust their behavior accordingly. Scientists studying drought conditions have found that trees exposed to water stress can adapt by closing their stomata (leaf pores) more quickly in subsequent droughts, effectively conserving water more efficiently.
This type of memory is biochemical, not neurological — but it challenges long-held assumptions about the limitations of plant intelligence. These adaptive responses allow trees to survive in changing climates, exhibiting that they are far more dynamic and responsive than we used to believe. In other words, your neighborhood oak might not just be standing there passively. It’s strategizing!
3. Trees Release Chemicals That Calm You Down
Ever noticed how a walk in the woods seems to melt your stress away? There’s science behind that. Trees release organic compounds called phytoncides, which help them protect themselves from insects and pathogens. When we breathe these chemicals in, they can reduce blood pressure, lower stress hormones, and boost immune system activity.
This effect is so powerful that Japan developed an entire practice around it called “shinrin-yoku,” or “forest bathing.” No hiking boots are required — just slowly walking through a wooded area and breathing deeply is enough to trigger a relaxation response.
Studies have even found that hospital patients recover faster when they have a view of trees from their window. Clearly, nature is a medicinal tool for all of us to utilize.
4. Urban Trees Can Cool Cities by Up to 9°F (5°C)
Trees are literal climate control systems. In cities, where pavement and concrete absorb and radiate heat, trees act as natural air conditioners. Through a process called transpiration, trees release water vapor into the air, which cools the surrounding environment. Combine that with the physical shade they provide, and trees can reduce temperatures in urban areas by up to 53.6°F!
This cooling effect has direct impacts on human health. During extreme heat events, shaded neighborhoods experience lower rates of heat-related illness and death. That makes tree equity (ensuring every neighborhood has access to tree cover) a matter of environmental justice. So the next time you step under a leafy canopy on a hot day, remember that tree might be saving lives.
5. One Tree Can Absorb Up to 48 Pounds of Carbon Dioxide Per Year
Trees are carbon sinks, which are natural systems that absorb and store carbon dioxide (CO2), the most prevalent greenhouse gas driving climate change. A single mature tree can absorb over 48 pounds of CO2 per year. Over 40 years, that’s nearly a ton of CO₂ removed from the atmosphere, and it is all just from one tree.
This makes trees essential allies in the fight against climate change. Forests worldwide absorb roughly 2.6 billion tons of CO2 annually, offsetting about one-third of the carbon emissions from fossil fuel combustion.
But deforestation is rapidly threatening this carbon buffer. When trees are cut down or burned, that stored carbon is released back into the atmosphere. Protecting and expanding tree cover is one of the most cost-effective climate solutions available today.
6. Some Trees Can Live for Thousands of Years (and Don’t Die of Old Age)
Unlike humans and most animals, trees don’t have a fixed lifespan. That means they don’t die of old age in the typical biological sense. In the absence of disease, drought, and human interference, many trees can theoretically live forever.
Some of the world’s oldest living trees are over 4,000 years old. Take the bristlecone pine, for example. Found in the White Mountains of California, these ancient beings have weathered ice ages, lightning strikes, and windstorms. One particular tree named “Methuselah” is estimated to be 4,853 years old, making it the oldest known non-clonal organism on Earth.
Even when they appear dead above ground, parts of a tree’s root system continue living underground and they can also regenerate into a new tree. Trees are the ultimate survivors.
Why Trees Deserve More Than Just Our Admiration
From city sidewalks to coastal mangroves, trees are working silently behind the scenes to cool our planet, connect ecosystems, reduce stress, and capture carbon. They’re known as the pretty plants in the background, but ultimately, they are essential to life on Earth.
As we celebrate World Mangrove Day, let’s remember that every tree counts. And with deforestation and climate change threatening forests around the world, the time to act is now.
If you’re feeling inspired to help, check out EarthDay.org’s Canopy Project, which is a global reforestation initiative that plants trees in communities that need them most. Whether you’re planting a tree in your backyard or supporting global restoration efforts, you’re part of a solution that grows over time.
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