Malcolm North is the lead author of a new study on forest resiliency. He's a research scientist with the U-S Forest Service and a professor at U-C Davis. "You'd have to take out about 80% of the trees to get back to the level of density that we used to have back in 1900 and 1910," said North.
North added that forests in the early 1900s had about 30-trees per acre. Today, it's around 200. "It could be that that very low density was one of the key factors as to why those historical forests were so able to persist through stresses in the past," said North.
North says in today's forests, too many trees are competing for less water amid drier and hotter conditions. His study is published in the journal "Forest Ecology and Management."