People work to reforest Allegheny National Forest in Pennsylvania circa 1934.
Photograph: Universal History Archive/Universal Images Group via Getty Images

Planting trees, we have noted, is smart policy.  Some campaigns may have stretched beyond scientific evidence, but science has given us plenty to go on:

Very cool: trees stalling effects of global heating in eastern US, study finds

Vast reforestation a major reason for ‘warming hole’ across parts of US where temperatures have flatlined or cooled

Civilian Conservation Corps workers plant 15,000,000 trees across the wastelands of southern Mississippi on 11 April 1940. They are part of the United Forest Service which will re-establish forests destroyed by logging and lumbering operations decades ago. Photograph: AP

Trees provide innumerable benefits to the world, from food to shelter to oxygen, but researchers have now found their dramatic rebound in the eastern US has delivered a further, stunning feat – the curtailing of the soaring temperatures caused by the climate crisis.

While the US, like the rest of the world, has heated up since industrial times due to the burning of fossil fuels, scientists have long been puzzled by a so-called “warming hole” over parts of the US south-east where temperatures have flatlined, or even cooled, despite the unmistakable broader warming trend.

A major reason for this anomaly, the new study finds, is the vast reforestation of much of the eastern US following the initial loss of large numbers of trees in the wake of European settlement in America. Such large expanses have been reforested in the past century – with enough trees sprouting back to cover an area larger than England – that it has helped stall the affect of global heating.

“The reforestation has been remarkable and we have shown this has translated into the surrounding air temperature,” said Mallory Barnes, an environmental scientist at Indiana University who led the research. “The ‘warming hole’ has been a real mystery and while this doesn’t explain all of it, this research shows there is a really important link to the trees coming back.”

There was a surge in deforestation from the start of the US’s early colonial history, as woodland was razed for agriculture and housing, but this began to reverse from around the 1920s as more people began to move into cities, leaving marginal land to become populated again with trees. The US government, meanwhile, embarked upon an aggressive tree-planting program, with these factors leading to about 15m hectares of reforested area in the past century in the eastern US…

Read the whole article here.