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VEGETATION MANAGEMENT |
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As the population of Los Angeles County increases, further expansion of residential areas into the Wildland-Urban interface is inevitable. Panoramic views, wildlife, fresh air, and solitude are just a few of the reasons that tempt people to locate in the brush areas of Los Angeles County. The rewards may be numerous, but the increased risk of wildland fires, flooding, and erosion poses a serious threat to life and property.
The County of Los Angeles Fire Department created the Vegetation Management Program in 1979 to develop strategies for responding to the growing fire hazard problem. These include:
Los Angeles County encompasses a land area of 4,000 square miles. 47% of this area is mountainous, while the remainder consists of alluvial valleys, coastal plains, and high desert. The mountains ranges within the County run from east to west. The main canyon drainages flow north and south. This natural topography has created airflow patterns linking the desert area with the Pacific Ocean. During periods of high meteorological pressure zones over the deserts, hot, dry, northerly winds known as Santa Anas follow these paths. The high frequency of fires in these areas has earned them the name fire corridors. Prominent fire corridors in Los Angeles County include Malibu, Arroyo Seco, and San Gabriel Canyons.
The vegetative ecosystem present on most of the watersheds in Los Angeles County is chaparral. The term applies to the shrubby vegetation seen on both coastal and inland hillsides. Chaparral can be separated into two types; soft chaparral (usually called coastal sage scrub) and the taller hard chaparral. Chaparral is dominated by evergreen and drought deciduous shrubs 1 to 15 feet tall. Most of these plants are recognized by their tough, leathery leaves that reduce water loss in the dry climate. Many chaparral plant species contain volatile oils which produce a strong odor and increase their flammability. Common examples include various species of Ceanothus, Manzanita, Sage, Sumac, Toyon, and Chamise. Chaparral ecosystems are very efficient at controlling erosion and protecting watersheds. The deep root systems of these plants help to stabilize slopes and allow them to thrive in the dry Mediterranean climate of Southern California. Chaparral plant communities depend upon fire as an integral part of their life cycle, and periodic burning is essential in order for these communities to rejuvenate. As unburned plants grow older, the amount of dead material increases dramatically. By age 50 as much as 50% of an individual plant may be dead. Where chaparral plants are uniformly old, and cover a broad area, fires tend to be large and devastating.
There are 5 methods currently being used by the County of Los Angeles Fire Department to manage over-aged chaparral stands:
The confined application of fire to a preselected area of land in order to minimize the amount of fuel in the area. Prescribed fires are carried out only under specific weather and fuel conditions, and is used to mimic nature's own process of regeneration.
The use of mechanical equipment to reduce vegetation in an area. Equipment consists mainly of a bulldozer, in combination with a "brush crusher", a brushrake, disk or anchor chain, which crushes or removes the vegetation.
The application of growth inhibitors, defoliators or killers to reduce highly flammable herbaceous or poisonous plants such as annual grasses or poison oak.
The reduction of plant volume using grazing or browsing animals, such as goats, to hold growth back and maintain low fuel volume.
The use of manual labor to remove brush with an assortment of tools including the Pulaski, hand axe, Grubbing hoe, chain saw, handsaw and others to modify vegetation arrangement. This is the most common method used by property owners to meet Fire Code requirements.
There are many data gathering techniques that provide vegetation managers with information necessary to carry out their programs. The data can help identify project areas and predict the condition of the chaparral as well as anticipate fire behavior. Live fuel moisture plant samples are taken at regular intervals and weighed to determine the moisture content in Chaparral. It is a major determinant in how the brush will burn. These measurements, when used in conjunction with other data, can be used to appraise fire hazards and predict fire behavior for use in fire control, fire prevention, and prescribed fire activities.
Proper weather conditions are critical for prescribed burns. Temperature, humidity, and wind must constantly be monitored in order to maintain a safe operation.
The County of Los Angeles Fire Plan Unit is responsible for implementing the California Fire Plan, a statewide framework for minimizing costs and losses from wildland fires. The Fire Plan Unit utilizes a Geographic Information System (GIS) platform to identify high hazard\high value areas and communities at risk in the wildland-urban interface. The identification of these fire hazard\risk areas is achieved by assessing and validating the fire environment components (Fuels, Weather, Topography, and Assets at Risk) in Los Angeles County. Areas identified through the Fire Plan process as Communities at Risk (CAR) and\or “Very High Fire Hazard Severity Zones” (VHFHSZ), are targeted for focused Pre-Fire Management projects by the Department’s Vegetation Management Program. Pilot Weather Balloons and Smoke Management The release and tracking of weather balloons to measure wind speed and direction allows managers to predict where smoke from a prescribed fire or chemicals will drift. Methods of treatment can then be carried out under conditions which keep these elements away from structures, roads and developed areas. Differences in wind patterns at ground level and aloft may predict possible changes in fire behavior.
Natural Occurrences Affecting Chaparral The health of the chaparral communities can vary. Drought, frost and abnormally high rainfall can cause vegetation die back. Other possible causes for dieback range from fungus infections to air pollution side effects. Research and Post Burn Evaluations Comparison of pre- and post-treatment evaluations are conducted to determine the effects of vegetation management treatments. Vegetation condition, erosion, effects on wildlife and adverse environmental factors are a few of the subjects being studied. Close monitoring and record keeping of effects allows Fire Department managers to continually improve vegetation management techniques.
State of California Senate Bill No. 1704 sets forth the guidelines for prescribed burning in California. This Bill grants the Los Angeles County Fire Department the authority to burn brush covered lands in order to reduce hazardous wildfire conditions. A private landowner may have up to 90% of the costs incurred for prescribed burning covered by the Vegetation Management Program if their primary objectives include the following: conversion of brush-covered areas into grazing land, fire prevention an protection, watershed protection and conservation, or range and forage improvement. If all of the terms of the burning permit are followed and the fire escapes, fire suppression costs will be covered under a third party liability policy of insurance.
This agreement allows the Fire Department to act as the lead in cooperation with other governmental agencies in projects concerning natural resources. On prescribed burns where several agencies share an interest, it plays an especially important role.
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