Healthy Forest Initiatives
A Thinner Forest Is a Healthy Forest ...
... and a Healthy Forest Is a Fire-Resistant Forest
Healthy Forest — A Historical Perspective
Prior to the 20th century, many mountain forests in the central and southern regions of California had fewer trees than they do today. This is because a hundred years of fire suppression and timber management allowed more trees to live longer than they ever had before.
These two photos of Yosemite Valley illustrate this concept. (Photos courtesy Gruell, George, “Fire in Sierra Nevada Forests: A Photographic Interpretation of Ecological Change Since 1849,” Mountain Press Publishing Company, Missoula, MT, 2001.)
This photo shows the upper Yosemite Valley in 1899 with meadows occupying much of the valley floor. (Courtesy Robert Gibbens, H.G. Peabody photo) (Click on the image to enlarge it.)
This photo shows the same location in 1994 crowded with dense conifers and woody plants. (Larry Davis photo) (Click on the image to enlarge it.)
"Today's forests stand in sharp contrast to historic forests that were more open because of lightning strikes and native American-ignited fires," says Thomas M. Bonnicksen, Ph.D., author of "Protecting Communities and Saving Forests" (The Forest Foundation, 2007).
A similar situation occurred in the San Bernardino Mountains, resulting in an overstocked forest that became unable to sustain itself when it was hit with repeated years of drought and the subsequent bark beetle infestation. An overstocked forest is also more susceptible to catastrophic wildfire.
Because the moisture content of the trees and brush is so low, it makes them more vulnerable to fire and parasites, such as the bark beetle. Thinning green vegetation not only reduces the fire danger, it helps restore the vigor of the drought-afflicted forest by freeing up more resources — water, minerals and sunlight — for the remaining trees and vegetation.
That's why a thinner forest is a healty forest.
Thinning Live Trees
The problem fire protection officials face is that not only does green vegetation burn, the forest is overstocked — 100 to 200 trees per acre, where a healthy forest has 40 to 60 trees per acre. Thinning green vegetation not only reduces the fire danger, it also frees up resources for the remaining plants and trees, making them more healthy, restoring their vigor and making them more resistant to fire as well as infestation by bark beetles and other parasites.
That’s why the focus of the Mountain Area Safety Task force has shifted from the removal of dead and diseased trees to thinning green vegetation. This includes shrubs, brush and live trees up to 10 inches in diameter.
Although MAST will continue removing dead trees through the end of 2008, property owners also need to thin the live trees and vegetation on their property to gain an upper hand on the bark beetle infestation and reduce the risk of catastrophic wildfires like the Grand Prix and Old fires in 2003.
Thinning green vegetation also helps property owners create a defensible space around their homes. It is recommended that trees be spaced 20 to 30 feet apart (trunk to trunk), depending on the ground slope and other factors. In addition, this will create a park-like environment.
A crown fire flares skyward in an overstocked forest, while a fire in a healthy forest is more likely to remain low to the ground and easier for firefighters to contain.
Forest Care partners, the National Forest Association and CAL FIRE, working under a grant from the USDA Forest Service, will reimburse property owners up to 75 percent of the cost of implementing a qualified tree thinning plan.
Read a Case Study on this program.
For more information:
Property owners may also obtain tree thinning advice from a licensed forester, at no charge, by contacting:
California Department of Forestry and Fire Protection:
San Bernardino Unit:
ReLeaf, an organization devoted to developing healthy forests in California, is working to educate the community about appropriate seedling selection and planting. Unlike some non-native trees that require additional watering to survive, native trees do not need special care.
For more information about ReLeaf and for contacts and seedling suppliers:
(866) 923-3473 (toll-free)
Children’s Forest Association
Children can also play an important role in the restoration process. The Children’s Forest Association has created a hands-on curriculum called Great Seeds Native Plant Restoration Program.
Through this program, children can germinate native seeds, monitor the success of restoration projects, and share their knowledge with the community by leading greenhouse tours and educational presentations. For more information and to learn how to get involved:
Working together, we can prevent catastrophic wildfires.