How many trees are in the world? 3 trillion, apparently

3 Sep 2015

In one of the most detailed surveys ever undertaken of the world’s forests, it appears that across the globe there are approximately 3 trillion trees, but a significant number of these are under threat.

The question of how many trees are in the world is not just an opportunity for a brain-teaser, but vital in terms of understanding the rate of deforestation globally, particularly when millions of trees are cut down daily.

But now, a team from Yale University has gone to great lengths to combine data from satellite imagery, forest inventories and supercomputer-powered calculations to estimate the amount of trees at a square-kilometre level.

Publishing its results in Nature, the three trillion trees figure that has been generated has shown that since the start of major human civilisation the planet’s tree population has plummeted by almost half (46pc).

Using the current number, this amount would equate to 422 trees to every person on Earth.

From the 400,000 plots included in the study, the world’s densest forests were found to be located in the boreal forests in the sub-arctic regions of Russia, Scandinavia, and North America.

However, in terms of what were deemed the largest forests, those located in the tropics were found to account for 43pc of the world’s total trees.

Puts environment into perspective

With this new information, the 15 country-led study will be able to significantly increase the capability of major environmental models relating to climate change and the distribution of life across the planet.

Speaking of the report’s findings, lead author of the story, Thomas Crowther, said: “[Trees] store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services.

“Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don’t know where to begin. I don’t know what I would have guessed, but I was certainly surprised to find that we were talking about trillions.”

Adding the importance of comparing today’s number with the estimate at the dawn of human civilisation, Crowther added: “We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result. This study highlights how much more effort is needed if we are to restore healthy forests worldwide.”

Rainforest in Seychelles image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic