Controlled Burn Planned for Palomar Observatory Area

After more than a year of planning, state and national firefighters recently began preparing the extremely fire-prone area around Palomar Mountain Observatory for an extensive controlled-burn project that may take three to four years.

Working jointly, officials from the California Department of Forestry and the U.S. Forest Service have been meeting with Palomar residents to explain the project and decide when to begin burning, now set for late May.

One of the major concerns is protecting the observatory’s valuable 200-inch Hale telescope, which could be damaged by airborne ash.

The project is an effort to control aging chaparral, the flammable brush that blankets most of the county’s canyons and rural hills. Ironically, fire is beneficial for chaparral, providing a natural form of weeding and thus helping in its rejuvenation.

Without fire, stands of chaparral become thick with dead and dry debris over the years, turning many areas into huge tinder boxes.

The area around the observatory--from Palomar Mountain to Riverside and from Warner Springs to River Valley--is such a place.

A major fire swept through that area, for example, in 1928, burning 67,000 acres. The threat of a similar fire convinced the California Institute of Technology, which owns the observatory, to agree to the controlled burn because any fire of that magnitude would endanger the observatory itself and the hundreds of trees around it that were planted after the 1928 blaze.

The goal of the project is to accomplish through controlled burning the same results as a wildfire--but without damage to property, homes and buildings.

The firefighters plan to burn about 1,750 acres of a 2,500-acre area during the next three to four years. Ownserhip of the land is part private, part federal.

Around the observatory, firefighters are creating perimeter controls and cutting up the brush for easier burning around the hundreds of trees. A privately owned machine, the Shar 20, touted as the only one of its kind in Southern California, can crush about one acre of brush each hour.

“We wanted to target this hazardous area, start breaking up the chaparral . . . because the area hasn’t burned for such a long time,” said Greg Greenhoe, vegetation management program director for the Department of Forestry. “Many of the species out there that burn, such as the chamise and scrub oak, are types of plants that need fire to recycle themselves.

“They build up over a period of years and, because Southern California is a relatively dry climate, there is not enough moisture for organic matter to break down. It just keeps building up and the environmental factor that causes that nutrient recycling is fire. Once every 40, 50 or 60 years, fire will sweep through an area and recycle those nutrients back into the soil and the whole process starts over again.”

If a major wildfire swept the area, however, it would create much more extensive damage, burning not only the older chaparral, but the newly sprouting shrubs as well. John Gray, the department’s chief of resource management, said fighting a major wildfire would be far more expensive than the cost of controlled burning, which is $15 to $50 an acre.

But even with a controlled-burn situation, there is a threat to the observatory’s 200-inch Hale telescope.

“Anytime there is any kind of forest fire or anything putting out a lot of ash into the air, there is concern we wouldn’t be able to open the observatory domes because the ash would be caustic to the aluminum surface” of the telescope’s mirror, said Merle Sweet, assistant superintendent at the observatory. “The amount of the ash depends on a variety of factors, but as a generalized rule the timing” of when the fire is is started is the most important.

“I would say it is possible we would have to shut down, but for (what) amount of time I wouldn’t even want to estimate. It could have a harmful effect, but for the overall good of the observatory, the area has to be burned. The whole area is very potentially dangerous; it is a threat to everyone.”

Gray said officials mapping the controlled-burn program, which tries to burn about 8,000 acres a year statewide, took into account many factors before approaching Caltech with their proposal.

“A lot of things have to be considered--you can’t just say, ‘I am going to go out and burn today,’ ” Gray said. “We have to physically study the project to determine such things as will we have to install fire lines or perimeter control, then usually (we) talk to the neighbors. We also have to determine how much we are going to pay an archeologist to determine . . . environmental impact.”

Gray said sometimes a controlled burn does get out of control but firefighters take many precautions to prevent this. A “prescription window”--the favorable environmental conditions that allow for safe burning--includes the humidity, the temperature and the age and moisture content of the brush. How close the time is to fire season is also considered because fire trucks and crews must be available, not off fighting other fires.

“There have been escapes,” Gray said. “It’s risky. Sometimes we are burning right behind people’s houses. . . . Of course, we want to do it as safely as possible, but sometimes brush is difficult to burn so you have to burn during natural fire conditions.

“There are problems sometimes. The fire can jump your lines. There are very (few) complaints about the program from neighbors, unless they are allergic to smoke, and then we tell them ahead of time. One important thing to realize is that the brush is going to burn regardless if we do it or it burns under a hot August fire, which would be worse.”

Planners also consider how the burning may affect the natural habitat, said Roy Woychak, assistant resource officer for the San Diego branch of the U.S. Forest Service.

“We try to create a natural situation because the brush has evolved over thousands of years,” Woychak said. “For example, if it is a deer habitat, we don’t want to burn in the fawning season. Or in the middle of winter, you might have bald eagles’ roost sites up there. You want to burn it when it is ready, simulate a natural condition.”

The California Department of Forestry first became involved with prescribed burning in the 1940s when it issued burning permits to large-scale ranchers who wanted to burn parts of their land to provide forage for cattle. In 1981, a partially state-funded program was created, in part to take the risk out of burning done by ranchers, Gray said. Since 1981, more than 30,000 acres have been scorched by the program.

Other controlled burn projects in the county include the burning of 600 acres at a Girl Scout camp near Julian; 1,400 acres on the north side of Ramona, and a three-year plan to burn 850 acres at the San Diego Wild Animal Park.

The program’s “goal may be 8,000 acres a year, but we rarely reach that,” Greenhoe said. “We usually do about 4,000. We try to do that much, but we just can’t possibly do it. If you know the area and you study the pattern of fires, you would see how much really needs to be burned to prevent a major wildfire. But we do the best we can. We know there are going to be wildfires and even 8,000 acres is just not enough.”