document: Prolonged drought , bark beetles and a rare fungus are drying out and killing brush and trees that surround many Southern California neighborhoods , creating the potential for one of the worst wildfire seasons in decades , fire officials warned Monday . A map released Monday by the Los Angeles County Fire Department showed that some of the most vulnerable fire zones can be found this summer in chaparral-covered foothill and mountain-canyon slopes beside densely developed residential districts of Los Angeles and its suburbs . The map was released as the state Department of Forestry officially opened the region 's 1990 fire season , which means its firefighting crews have been placed on higher alert and various fire prevention regulations are now in effect . While the fire-season announcement came only two to three weeks earlier than usual in the vulnerable foothills , it was a full two months ahead of schedule in the heavily wooded mountain terrain of Southern California 's national forests . `` The last really good rainfall was back in ' 82-83 , so our brush really has n't recuperated in seven years , '' said Gordon Rowley , a fire management specialist with the U.S. Forest Service . `` Unless we get a hurricane or something -- and that 's not very likely -- we 're going to have a very bad year . '' Rowley said other Western states also are experiencing drought , `` which means they wo n't be able to send us the firefighting forces they normally can deploy out here ... . It does n't look good . '' Los Angeles , which has an annual average of 14.93 inches of rainfall , has received 6.18 inches so far this season , promising to make this the driest season in 30 years . The rainfall season , which runs from July 1 to June 30 , is almost over for 1989-90 , and Southern California seldom gets much measurable rain in late May and the month of June . In 1982-83 , 31.25 inches of rain fell on the city , more than twice the seasonal average . But since then , the annual rainfall here has averaged only 11.57 inches . Rowley said the long drought has weakened the vegetation in Southern California , making it more vulnerable to disease and infestation by pests . He said that with normal rainfall , pine trees are vigorous enough to fight off bark beetles , which bore into trunks and limbs to lay their eggs . He said healthy trees repel the insects with a flow of pitch that suffocates them and forces them out of the bark . But during the current dry spell , the trees have n't been able to produce enough sap to rid themselves of the beetles . Rowley said the insects have proliferated , killing vast stands of pines and leaving tinder-dry fuel for fires . The problem is acute in the Cleveland and San Bernardino national forests . In foothill districts closer to Los Angeles , a fungus that preys upon drought-weakened brush has killed as much as 60 % of the chaparral in some portions of the Santa Monica and San Gabriel mountains . The fungus , first observed about eight years ago , attacks broad-leafed plants such as mountain lilac , manzanita and sumac , some of the more fire-resistant species of brush . Officials said large patches of this dead and dying brush now mottle the hillsides , ready to burst into flame at the slightest spark . And because of the drought , even the live brush is more incendiary than usual , officials said . Capt. Scott Franklin , a vegetation management officer with the county Fire Department , said the dead trees and dry brush combine to form a fuel source so volatile that `` any ignition now could become a major fire . '' Fire officials generally have responded to the threat with increased training and requests for federal money to pay for extra firefighting personnel . Each densely thicketed acre of hillside chaparral contains about 60 tons of brush , he said , and that 60 tons has about the same fuel energy as 3,750 gallons of gasoline . `` Then , if you put 80 m.p.h. winds -- the kind of Santa Anas we get in September -- behind all that , a fire can consume 100 acres a minute and keep right on going , '' Franklin said . `` You 're talking an energy release equivalent to several nuclear events , the energy of a number of Hiroshimas . '' The county Fire Department map shows that the most threatened residential areas include a number of hillside and canyon communities within the city of Los Angeles , including parts of Baldwin Hills , Hollywood , the Los Feliz district , Tarzana , Encino , Sherman Oaks , Sunland and Sylmar . Especially threatened suburban communities include portions of Rolling Hills , Rancho Palos Verdes , Beverly Hills , Glendale , Pasadena , Altadena , Arcadia , Monrovia , Bradbury , Duarte , Azusa , Glendora , Claremont and Whittier . Doug Allen , a fire prevention officer with the state Division of Forestry , said residents should clear tall grass , brush , trash , firewood and other combustibles at least 30 feet from any building . FIRE STRESS AREAS Map shows largely undeveloped land where dead brush and a lack of leaf moisture in live brush create high fire hazards . Fire officials say these are areas where blazes can start and expand rapidly , spreading from open land to homes and other structures . What You Can Do Fire officials have a number of recommendations for residents of areas where the wildfire danger is high : Clear brush and grass a minimum of 30 feet away from any buildings . Do not not store firewood , trash or other combustibles within 30 feet of any building . Do not smoke , barbecue or build a campfire outdoors until the rainy season resumes in the fall . Do not drive motor vehicles in off-road areas where brush and grass grow . Exhaust sparks and hot mufflers start many wildfires . Do not use an indoor fireplace that is not equipped with a spark-arresting device . In case of fire , turn off all tap water unless instructed otherwise . Indiscriminate use of water can lower the pressure to those who need it to fight the blaze .
extractive_keyphrases: wildfire seasons southern california neighborhoods fire officials vulnerable fire zones fire prevention regulations wildfire danger high fire hazards fuel source vulnerable foothills prolonged drought rainfall season