Researcher: Wild California just a memory

SAN FRANCISCO, Feb. 29 (UPI) -- A California researcher said nearly all of California's 31 million acres of forest have been changed in some way by humans.

Pollution, roads, mining, logging and development have left obvious marks on the California wilderness but urbanization and fire suppression are the greatest threats to forest health, the San Francisco Chronicle said Friday.

Forest fires near homes have to be controlled, removing fire as a natural method of keeping the forest understory -- the area of a forest which grows in the shade of forest canopy -- from becoming overgrown. State fire officials said development in "wildland-urban interface zones" contributed to the devastation from last wildfires.

The U.S. Forest Service said the overly dense forests combined with drought have played a part in recent bark beetle infestations. Studies have shown that 25 percent of California's forestland, close to 4.9 million acres, are at risk of deadly insect infestations and disease during the next 15 years.