HEAVY RAINS MAY KILL TREE-DESTROYING BARK BEETLES IN AREA 'WIMPY' SPECIES ON WESTERN SIDE OF FOREST LIKELY TO BE AFFECTED MOST.

Byline: Patricia Farrell Aidem Staff Writer

ANGELES NATIONAL FOREST - Besides the obvious, this year's unusually heavy rain has put a damper on the volatile fire conditions of recent years by drenching drought-stricken stands of trees that were vulnerable to devastating bark beetles.

Fire experts will argue that rainy winters can increase fire danger as the months pass because they spawn grasses that dry in summer and carry flames to the brush.

But Laura Merrill, an entomologist for the U.S. Forest Service, said engraver bark beetles that have infested pines and the white fir trees in the Santa Clara-Mojave Rivers District of the Angeles National Forest - particularly in the Castaic area - likely won't survive a year so wet.

More than 20 inches of rain has fallen in some areas of the forest since Oct. 1, well more than the average for an entire year.

``Some of the bark beetles will be very much affected by rain, mostly the engraver beetles,'' Merrill said. ``They don't do well in plants that have any level of hydration. I would expect to see a lot less mortality next year. That's good news.''

Pests including various species of bark beetles have infested trees throughout the Angeles and other Southern California forests and were blamed in part for the devastating fires of 2003 that swept through San Bernardino and San Diego counties. Towering stands of pines, weakened by drought, had been attacked by various bark beetles that thrive on trees weakened by drought and disease. These dying trees were the fuel that drove flames across hundreds of thousands of acres of forest land.

Hearty, more aggressive bark beetle species are found in California's southeastern forests and could hold up through a stormy winter, Merrill said.

But it's a ``wimpy'' species of bark beetles - the engraver - that has been found on the western side of the Angeles National Forest, Merrill said.

Last year, beetles killed more than 50 trees at the Castaic Lake Recreation Area, which backs up to the Angeles National Forest. Within the forest, the disease spread and added to high fire-danger conditions. The bugs had proliferated during last year's mild winter and the lack of rain in recent years stressed trees, making them perfect hosts for pests, a Los Angeles County forestry official said.

Cid Morgan, district ranger for Santa Clara-Mojave district, saw 37,000 acres of the land in her jurisdiction burn in wildfires in July, firestorms that had experts worried conditions would be much worse by September and October, the normal height of the brush fire season. Now she's worried about rain-induced landslides in the burn areas, but glad nevertheless to see the current weather.

``It's great for the trees,'' she said. ``It had gotten so dry.''

Still from the scientist's point of view, the beetles are good for the forests because they naturally thin the trees, devouring the dying ones, which gives the healthy trees more water and sunshine, Merrill said.

``They're native and they're beneficial in a normal forest situation because they take out trees that are dying from something else.''

Patricia Farrell Aidem, [phone]

pat.aidem(at)dailynews.com