Scientists at Oregon State University have learned that Douglas fir and hemlock trees struggle to transport water from their roots to their crowns in the winter.
Conifers transport water from the soil to branches 300 feet off the ground using a network of pipe-like cells, each about the size of an eyelash. If the cells freeze and thaw, researchers found that air bubbles get trapped inside them.
Kate McCulloh is one of the study’s authors.
“When those tubes become full of air bubbles instead of full of water, it is harder for the plant to move the water that it needs every day.”
McCulloh says that those bubbles can shut down half the water transport system in the top of a Douglas fir in the winter.
But by the time summer rolls around and the trees get thirsty, they have found some way to flush the air back out of their pipes.
How they do that is still a mystery.