Hi, I'm Scientific American Podcast Editor Steve Mursky.

And here's a short piece from the May 2018 issue of the magazine in the section we call

Advances, Dispatches from the Frontiers of science, technology, and medicine.

Sweaty trees by Yasmin Saplacolu.

Recent summer temperatures in parts of Australia were high enough to melt asphalt.

As global warming cranks up the heat and climatic events intensify,

many plants may be unable to cope, but at least one species of eucalyptus tree can withstand extreme heat by continuing to sweat when other essential processes taper off. As plants convert sunlight into food or photosynthesize,

they absorb carbon dioxide through pores on their leaves. These pores also release

water via transpiration, which circulates nutrients through the plant and helps cool it by evaporation.

But exceptionally high temperatures are known to greatly reduce photosynthesis,

and most existing plant models suggest this should also decrease

transpiration, leaving trees in danger of fatally overheating.

Because it's difficult for scientists to control and vary trees condition in their natural environment,

little is known about how individual species handle this situation.

Ecologist John Drake of the Sunni College of Environmental Science and

Forestry and his colleagues grew a dozen parameter red gum, that's eucalyptus

parametensis, in large climate-controlled plastic

pods that isolated the trees from the surrounding forest for a year in Richmond, Australia.

Six of the trees were grown at ambient air

temperatures and six at temperatures three degrees Celsius higher. The

researchers withheld water from the surface soil of all 12 trees for a month to simulate a mild dry spell,

then induced a four-day extreme heat wave.

...