Climate change making forests shorter and younger: Report

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New Delhi (NVI): Climate change is speeding up the death of trees, slowing their growth and making forests across the world younger and shorter, according to a new report.

A team of more than 20 scientists analysed the state of the world’s forests, using data from 160 previous studies and satellite imagery captured over decades.

In the report published in Science magazine, researchers show that the world lost roughly one-third of its old grown forest between 1900 and 2015.

In addition to this, in North America and Europe, where more data was available, they found that tree mortality has doubled in the past 40 years.

Decades of logging activity and forest clearances, increasing temperatures from human-made climate change are seen as a significant factor, the researchers said.

Similarly, in Brazil, both human activity and wildfires have cleared large tracts of Amazon rainforest. Likewise, Russia and North America have lost vast areas of tree canopy.

The report also stated that, more than 55,000 square kilometers of Russia’s tree cover was cleared in 2018 – roughly equivalent to the size of Croatia.

The loss of mature trees is harming global biodiversity levels, as animal habitats disappear and ecosystems are disrupted, report added.

Meanwhile, what are left are younger trees, less able to reach for the skies due to warming temperatures, which limits photosynthesis and stunts tree growth.

“Unfortunately, mortality drivers like rising temperature and disturbances such as wildfire and insect outbreaks are on the rise and are expected to continue increasing in frequency and severity over the next century,” said the lead author of the study, Nate McDowell of the US Department of Energy’s Pacific Northwest National Laboratory.

“Hence, reductions in average forest age and height are already happening, and they’re likely to continue to happen,” McDowell added.

Furthermore, trees act as natural sponges to absorb carbon dioxide from the planet’s atmosphere. Besides, when mature forests which are generally bigger and can hold more carbon than younger areas of canopy die, the planet’s capacity to store CO2 is diminished, exacerbating climate change.

Another study, led by Martin Sullivan from the University of Leeds and Manchester Metropolitan University, suggests that tropical forests are resistant to small temperature changes until they reach a threshold of about 32 degree Celsius.

Beyond this temperature, trees stop growing and begin to die, releasing carbon back into the atmosphere.

“The 32-degree threshold highlights the critical importance of urgently cutting our emissions to avoid pushing too many forests beyond the safety zone,” Sullivan said.

In addition to this, the World Economic Forum (WEF) has launched a global initiative to grow, restore and conserve 1 trillion trees. It aims to connect, mobilize tree planting and reforestation efforts to restore biodiversity and fight climate change.

-RJV