14-05-21 Many have assumed that warmer winters as a result of climate change would increase the growth of trees and shrubs（灌木） because the growing season would be longer. But shrubs achieve less yearly growth when cold winter temperatures are interrupted...

14-03-13 Perched high on the bluffs（绝壁） of the big river valleys in the Midwest are some of the last remnants of never-farmed prairie grasslands. These patches, edged by forest, are slowly being taken over by shrubs. A recent University of Illinois study...