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They give us paper and fuel as well as vital ecological services, like cleaning the air, storing carbon, and providing

habitat.

We're talking about trees, of course.

But changes in the environment, largely caused by humans, appear to be causing profound

transformations in trees around the world.

In a new study, scientists reviewed global research on trends in tree birth, growth, and death.

They combined those data with an analysis of deforestation.

And they found that worldwide, older trees are dying at higher rates than in the past,

due to factors like rising air temperature, wildfires, drought, and pathogens.

Most of the drivers of that decrease of large old trees are increasing themselves, such as temperatures

going up, droughts are more severe Wildfires, windstorms, and deforestation

are all, although variable across the globe,

they're generally increasing.

And so both the loss has already occurred, but we expect more continued loss of big old trees.

Nate McDowell, an Earth scientist at Pacific Northwest National Lab who is one of the study's authors.

So if we have an increasing rate of death,

particularly of the larger older trees,

what's left are the younger trees.

So that's why on average through the loss of bigger older trees

...