Small tree and bush growth at much higher density

Photo credit: Pixabay

Del Puerto Canyon, California

Drought, fire management and land use changes have led to denser forests in California

by Bob Yirka

EXCERPT

In analyzing the data, the researchers found that large tree density is lower in the more recent years than early last century, for all parts of the state, with some declines as high as 50 percent. In their place are small tree and brush growth, which they found has a much higher density than a hundred years ago. They also noted that over the same period, California has grown drier, as many studies have confirmed. It is the increased water stress, the team suggests, that is at least partly responsible for the change in tree densities. Another factor is fire management. In the past, before people arrived, fires, generally due to lightening strikes would start, and burn thousands of acres before dying natural deaths. That would allow for new growth, which would eventually lead to tall tree growth. Now, whenever a fire starts, it is put out as quickly as possible to protect homes and businesses in the area. The result is highly dense forests with dry small trees—the perfect conditions for fires to start and spread very quickly. The researchers also found that oak trees have grown more numerous while pine populations have declined—another result of the drier climate.

The study suggests that California forest managers are likely to be facing some tough decisions in the years ahead as the planet heats up and the state becomes drier.

Read the full article: Phys Org