Heated growth

The “urban heat island” effect is causing trees around the world’s cities to grow faster than those in the country, a new study finds.

Concrete and other heatabsorbing materials that make up the urban landscape store more heat than the ground in the country. This keeps cities significantly warmer, especially at night.

Researchers at the Technical University of Munich compared core samples of 1,400 trees from several countries around the world in both urban and rural settings.

They found that city trees of the same age as country trees were larger because they grew faster in the excess heat. Earlier studies found that global warming is causing faster tree growth in both urban and rural trees.