Environmental News for a Healthier Planet and Life

11 Surprising Facts About Trees


By Natalie Muller

Trees soak up carbon from the atmosphere, provide a home to wildlife and even improve our mental well-being. But did you know they can also "talk" to each other, and send out distress signals when under attack?

1. ​60,000 Different Species

There are around 3 trillion trees on Earth, according to a global study led by researchers from Yale University. That includes over 60,000 known tree species, more than half of which are endemic — meaning they're found in only one country. Brazil, Colombia and Indonesia are home to the most tree species. The bad news: there are 46% fewer trees today than at the start of human civilization.

2. Trees 'Migrate' to Escape Climate Change

Trees clearly can't uproot themselves and move, but their population centers can shift over time in response to climate pressures. A study looking at 86 trees species between 1980 and 2015 in the eastern United States found that 73% moved west, where rainfall is increasing. Others headed to the poles, apparently to escape heat. On average, they moved about 16 kilometers (10 miles) per decade.

3. Keeping Cities Cool

Trees not only give us shade, they can also mitigate extreme temperatures by transpiring — absorbing the sun's radiation and releasing water into the air through their leaves. Urban areas can become sweltering "heat islands" in summer. But a 2019 study from the US found that tree canopy cover of 40% or more could lower summer temperatures in cities by as much as 5 degrees Celsius.

4. Sucking Up Pollutants

Trees draw CO2 from the atmosphere and are therefore crucial in the fight against climate change. They can also use their leaves to filter particulate matter and toxic gases like nitrogen dioxide and sulphur dioxide from the air. A recent UK study found that silver birch, yew and elder trees could reduce particles at rates of 79%, 71% and 70% respectively.

5. Healing Power

Trees can reduce our stress levels and help us feel happier and healthier. Several studies have shown that spending time in nature, or even just looking at trees or flowers through a window, can lower blood pressure, boost the immune system, improve sleep, reduce depression and anxiety, and even speed up recovery after surgery.

6. Trees 'Talk' to Each Other

Forests have their own communication systems — almost like an underground internet —that allows trees to swap nutrients and send warnings about drought or disease. They interact via networks of soil fungi, known as mycorrhizal networks. Research by ecologist Suzanne Simard has shown that paper birch (pictured) and fir trees use this system to send water, carbon and nutrients back and forth.

7. Sending Signals in the Air

Trees can't flee if their leaves are being devoured by a hungry herbivore. But what they can do is release chemicals — volatile organic compounds — into the air to warn nearby members of the same species there's a threat in the area. Studies show that other trees respond by boosting their own production of anti-herbivore toxins, which, in the case of acacias (pictured), makes their leaves bitter.

8. Call for Backup

When besieged by bugs or parasites, some species, including apple trees, and tomato, cucumber and lima bean plants, release compounds into the air to alert the attackers' predator. Most often, these predators are insects. But a European study showed that trees infested with caterpillars also put out chemical signals to attract caterpillar-eating birds, such as the great tit (pictured).

9. Methuselah Has Lived Through a Lot

Trees are the oldest living organisms on Earth. One individual can survive hundreds, even thousands of years. According to the OldList, an officially dated record of ancient trees, the oldest known living individual is a bristlecone pine in California's White Mountains. Named Methuselah, it's around 4,850 years old. Its exact location is kept a secret to protect it from vandals.

10. Hyperion, the Giant

A photograph can't really do justice to the world's tallest trees: redwoods. The tallest known living specimen is a coast redwood called Hyperion measuring 115.85 meters (380 feet) — more than Big Ben or the Statue of Liberty. The giant, discovered in 2006 in California, is believed to be several hundred years old.

11. Other Record Breakers

California is also home to a giant sequoia named General Sherman, thought to be the biggest living tree in terms of volume. It stretches to a height of 83.8 meters and is 7.7 meters in diameter. The title of the world's widest tree goes to the Arbol del Tule (pictured), a Montezuma cypress in the Mexican state of Oaxaca. It has a diameter of 11.6 meters and a circumference of 42 meters.​

Reposted with permission from Deutsche Welle.

EcoWatch Daily Newsletter
Air France airplanes parked at the Charles de Gaulle/Roissy airport on March 24, 2020. SAMSON / AFP via Getty Images

France moved one step closer this weekend to banning short-haul flights in an attempt to fight the climate crisis.

Read More Show Less
A woman looks at a dead gray whale on the beach in the SF Bay area on May 23, 2019; a new spate of gray whales have been turning up dead near San Francisco. Justin Sullivan / Getty Images

Four gray whales have washed up dead near San Francisco within nine days, and at least one cause of death has been attributed to a ship strike.

Read More Show Less
A small tourist town has borne the brunt of a cyclone which swept across the West Australian coast. ABC News (Australia) / YouTube

Tropical Cyclone Seroja slammed into the Western Australian town of Kalbarri Sunday as a Category 3 storm before grinding a more-than 600-mile path across the country's Southwest.

Read More Show Less
A general view shows the remains of a dam along a river in Tapovan, India, on February 10, 2021, following a flash flood caused by a glacier break on February 7. Sajjad Hussain / AFP / Getty Images

By Rishika Pardikar

Search operations are still underway to find those declared missing following the Uttarakhand disaster on 7 February 2021.

Read More Show Less
Indigenous youth, organizers with the Dakota Access and Line 3 pipeline fights and climate activists march to the White House to protest against pipeline projects on April 1, 2021. Bill Clark / CQ-Roll Call, Inc via Getty Images

By Jessica Corbett

Indigenous leaders and climate campaigners on Friday blasted President Joe Biden's refusal to shut down the Dakota Access Pipeline during a court-ordered environmental review, which critics framed as a betrayal of his campaign promises to improve tribal relations and transition the country to clean energy.

Read More Show Less