Shrub Growth Decreases as Winter Temperatures Fluctuate as a Result of Climate Change, Triggering Premature Spring Growth

Many have assumed that warmer winters as a result of climate change would increase the growth of trees and shrubs because the growing season would be longer.  But shrubs achieve less yearly growth when cold winter temperatures are interrupted by temperatures warm enough to trigger growth.

Many have assumed that warmer winters as a result of climate change would increase the growth of trees and shrubs because the growing season would be longer.  But shrubs achieve less yearly growth when cold winter temperatures are interrupted by temperatures warm enough to trigger growth.

"When winter temperatures fluctuate between being cold and warm enough for growth, plants deplete their resources trying to photosynthesize and end the winter with fewer reserves than they initially had.  In the summer they have to play catch up," said Melanie Harsch, a University of Washington postdoctoral researcher in biology and applied mathematics.  She is lead author of a paper on the subject recently published in PLOS ONE.

The roots are especially sensitive to temperature fluctuations, Harsch said.  Warming winters result in higher root respiration, which uses up carbon reserves as plants make and release oxygen, leading to less carbon available during the regular growing season.

Shrub Growth Decreases as Winter Temperatures Fluctuate as a Result of Climate Change, Triggering Premature Spring Growth