Mountain forests are disappearing at an accelerating rate
The old-growth forest in southeastern British Columbia near Revelstoke is prized by the logging industry.
Logging, fires and agriculture are causing mountain forests to disappear at an increasingly rapid rate, according to a new study released Friday.
Mountains are home to 85% of the world's birds, mammals and amphibians, especially in forests, which makes the loss of these alarming for biodiversity.
Mountain forests covered 1.1 billion hectares of the planet in 2000, according to the authors of this study published in the journal One Earth >.
But at least 78.1 million hectares, or 7.1% of the total, disappeared between 2000 and 2018, they determined using data from satellites. This represents an area larger than the size of Texas.
And the pace of their disappearance is accelerating: recent losses were 2.7 times greater than at the turn of the century.
The authors of this work warn in particular that the most affected areas (42% of the total), and which also see the most significant acceleration, are the tropical mountain forests, which are home to a treasure of diversity and are the refuge of many endangered species.
“Loss in the mountain forest of the tropics is increasing very rapidly, more than in other regions. And the biodiversity is very rich in these places, so the impact is immense.
— Zhenzhong Zeng, study co-author
Altitude and steep slopes have historically limited human exploitation of these forests, the researchers note. But since the turn of the century, they have increasingly been targeted for their timber and agriculture.
Logging is responsible for 42% of the loss of mountain forests, followed by forest fires (29%), shifting cultivation (15%), and permanent or semi-permanent agriculture (10%), according to the study.
Shifting agriculture involves clearing land and using it for a few years before abandoning it until it become fertile again.
“The factors are different for different regions. For the boreal zones, it is caused by climate change, as there is a particularly marked increase in temperatures in the Arctic, favoring the fires.
— Zhenzhong Zeng, study co-author
We must reduce the use of fossil fuels to slow climate change, he stressed.
The expansion of agriculture is the factor largest for losses in Southeast Asia.
People plant more rubber trees or oil palms to get more product, says Zhenzhong Zeng. And they need more land to grow corn and feed their chickens.
Shifting cultivation takes place mostly in Africa and South America.
According to the study, the loss of mountain forests is most pronounced in Asia: 39.8 million hectares, slightly more than the half of the total lost.
South America, Africa, Australia and Europe also recorded significant losses.
“For the tropics, people need to live with the forest, not cut down the forest. ”
— Zhenzhong Zeng, co-author of the study
In some areas, scientists have observed regrowth, but not always of local species, and especially without compensating for losses, stressed Xinyue He, also a co-author of the study.
Forest preservation efforts must be intensified, she said, with more controls and regulations. According to her, establishing protected areas can help reduce losses.
