But what of the trees that live in chronic windy conditions? How have they evolved to counteract wind?
Let’s look first at a single leaf. Constant wind draws water out of a leaf, producing the same effect as a tree in drought. So tree leaves in windy areas are tough, leathery and are covered with waxy compounds that reduce water loss.
Stomata are the tiny leaf pores that control the exchange of gases and water. Most trees have their stomata on the upper surface of their leaves, which are exposed to sun and wind. But the stomata of tree species growing in windy habitats occur on the self-shaded undersides of foliage, to better retain water.
On wind-buffeted mountaintops, trees invest in wood strength instead of height. Trees that grow on the windward side have wood densities that are significantly higher than those of the same species that grow on the leeward side, even though they are just a few hundred feet apart.
Wind can also sculpt forest canopies. On the windy coast of Washington State, you’ll see asymmetrical crowns of Sitka spruce. The salt-laded winds of the coast shape their crowns into sideways teardrops.
These structural modifications demonstrate that although trees can’t control their environment, they can adapt and thrive – especially where winds blow strong and steadily.
