More than 3 trillion trees now grow on earth, finds study
More than 3 trillion trees now grow on earth, finds study
By AP, The Economic Times, September 3, 2015
The number is seven times more than scientists previously thought. But it's also trillions fewer than there used to be, a new study concludes.
WASHINGTON: More than 3 trillion trees now grow on Earth, seven times more than scientists previously thought. But it's also trillions fewer than there used to be, a new study concludes.
A United Nations-affiliated youth group had a goal of planting one billion trees and Yale forestry researcher Thomas Crowther was asked if planting that many trees would do anything to help combat human-made climate change. Trees capture and store heat-trapping carbon dioxide.
Crowther said first he had to figure out how many trees are on Earth and that number was far more than anyone expected: 3.04 trillion trees, according to a study published Wednesday in the journal Nature.
The previous estimate was 400 billion trees and that rough count was based on satellite images peering down from space. Crowther and colleagues used 429,775 ground-based measurements along with satellite measurements and computer models to get a more accurate figure.
"These things really dominate our planet," Crowther said. "They are the most prominent organisms on our planet and there are 3 trillion of them."
But Earth used to be covered with far more trees. Using computer models, Crowther and colleagues estimated that before human civilization Earth had about 5.6 trillion trees. So the number of trees on Earth has been chopped nearly in half.
Crowther mostly blames people. His study found that 15 billion trees are cut down each year by people, with another 5 billion trees replanted. That's a net loss of 10 billion trees a year. At that rate, all of Earth's trees will be gone in about 300 years.
"Humans are diminishing that huge population on such a global scale," Crowther said.
Nearly 1.4 trillion of Earth's trees are in tropical and subtropical forests, but that's also where the rate of forest loss is the highest, the study found.
So if there are so many trees on the planet, the planting of a billion trees wouldn't do too much to fight climate change on its own, Crowther conceded. But he said that didn't stop the tree planters group; they just upped their goal. On its website, Plant for the Planet says the objective is now 18 billion
Now that's over many decades, and it might be hard to find space, but it can be done, Crowther said.
Outside scientists such as Norm Christensen of Duke University said the way the study was conducted made sense and is well executed. But he wonders how useful it is to know the number of trees. Former U.S. Forest Service chief Mike Dombeck said the same thing, adding the issue is more than a number but the big picture of what trees do to help Earth and local ecosystems.
Crowther said he and his colleagues all wondered the same thing, but the detailed maps of forest density can help conservation efforts. For example, if a jaguar needs a certain number of trees to survive, this can help in rebuilding the right habitat for the large cat, Crowther said.
Also, it spurs people to realize how important it is to take care of and replant forests, Crowther said.
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Trees are the oldest living things on the Earth (at least as well as we know).
How do you feel about them being used on the doors of cars?
I'm surprised there are not more than three trillion. So the US government has five dollars of debt for every tree on earth.
I doubt that, only because without them humans die, and so there is no one left then to cut down trees...
One way to deal with desertification is to plant trees at the line where the desert starts . Then they need support like water and extra CO2 to thrive . This would work especially well in North Africa .
Pennsylvania has an area called the Delaware State Forest . This area is thick with growth and you'd never guess that the old growth forest was clear cut, ca. the mid to late 19th century. It took over a hundred years, but the new growth is so thick cell phones have "no bars". Conservation and forestry programs are imperative to regrowth. Tourists from as far away as New York and Philadelphia come to see it.
Yeah, I was only kidding, Woodie (because of your name and avatar). However, although furniture used to be made of solid wood boards previously, veneer over particleboard seems to be more usual these days - probably because solid wood is becoming too expensive.
And it is automatically assumed that humans killed more than that number. Without any proof at all.
I wish for once in my lifetime we can get a scientific announcement without the political slant.
Your comment is correct, NWM, because forest fires can be started by lightning, and without human firefighting they can be devastating (and sometimes notwithstanding).