Potrero Brush Clearance and Wildfire Mitigation
Vegetation Management and Wildfire Mitigation are required by property owners.
The State of California and Potrero have seen an increase in frequency and size of wild fires, including historic brushfires. Additionally, smaller brushfires have been accidentally started by well-intentioned residents performing brush clearance. Therefore, Potrero Council has approved an ordinances to increase requirements for brush clearance and wildfire mitigation in the Very High Fire Hazard Severity Zones. This ordinance establishes appropriate safety measures necessary to mitigate the occurrence of such fires.
Highlights of the new Potrero ordinance regarding Wildfire Mitigation include:
Use of metal cutting blades for grass or brush clearance shall be limited to those which are non-ferrous/non-sparking.
Brush clearance cannot be done on red flag days, when fire weather conditions are at their peak.
Individuals engaged in brush clearance operations shall not engage in any other activities during their actual clearance of grass or brush.
An approved fire extinguisher, or a pressurized garden hose with attached nozzle shall be within 10 feet of any grass or brush clearance operation, to quickly extinguish a small fire before it burns out of control.
A cell phone capable of dialing 9-1-1 for Potrero Fire Department shall be charged and readily accessible to the grass or brush clearance operation.
GENERAL CLEARANCE REQUIREMENTS
Owners of property located in the Potrero Very High Fire Hazard Severity Zone shall maintain their property in accordance with the Fire Code. Year-round compliance for wildfire mitigation shall be maintained as described below on all native brush, weeds, grass, trees and hazardous vegetation within 200 feet of any structures/buildings, whether those structures are on the owner’s property or adjoining properties, and within 10 feet of any combustible fence or roadway/driveway used for vehicular travel in Potrero.
1. Grass shall be cut to three inches in height. For brush clearance, native brush shall be reduced in quantity to three inches in height. This does not apply to individual native shrubs spaced a minimum of 18 feet apart, provided such shrubs are trimmed up from the ground to 1/3 of their height with all dead material being removed.
2. For trees taller than 18 feet, trim lower branches so no foliage is within six feet of the ground, and remove all dead material. For trees and shrubs less than 18 feet, remove lower branches to 1/3 of their height, and remove all dead material (see diagram below).
3. Trees shall be trimmed up so the foliage is no closer than 10 feet from the outlet of a chimney (see diagram below).
4. All roof surfaces shall be maintained free of substantial accumulation of leaves, needles, twigs and any other combustible matter. Maintain five feet of vertical clearance between roof surfaces and portions of overhanging trees (see diagram below).
5. All cut vegetation and debris shall be removed in a legal manner. Cut vegetation may be machine processed (i.e., chipped) and spread back onto the property at a depth not to exceed three inches within 30 feet of structures and six inches beyond 30 feet of structures. In addition, spread material shall not be placed within 10 feet of any usable roadside (in accordance with Fire Prevention Bureau Procedure No. 25)
The above general requirements also apply to landscape vegetation.
VEGETATION MANAGEMENT IS A YEAR-ROUND RESPONSIBILITY
Clear Early, Clear Often.
While all of California is subject to some degree of fire hazard, there are specific features that make some areas more hazardous; thus require wildfire mitigation. The California Department of Forestry and Fire Protection (CAL FIRE) is required by law to map areas of significant fire hazards based on fuels, terrain, weather, and other relevant factors. These zones, referred to as Fire Hazard Severity Zones (FHSZ), influence how people construct buildings and protect property to reduce risk associated with wildland fires. The maps were last updated in the mid-1980s and early 1990s.
Vegetation Management Program
As the population of Potrero 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 Potrero. The rewards may be numerous, but the increased risk of wildland fires, flooding, and erosion poses a serious threat to life and property.
An ongoing effort to analyze the history and effects of wildland fires in Potrero regarding wildfire mitigation:
Experimentation with different methods of reducing or removing fuels in fire prone areas as well as the evaluation of the environmental impacts and effects of these practices. Thousands of homes in the Potrero area have been lost in wildland fires. Many of these were lost due to the vegetation around them. Wildland fire behavior is strongly influenced by vegetation (fuel) type, fuel moisture, the arrangement and continuity of fuels, slope, aspect, and weather. This helps to provide a guideline on wildfire mitigation.
Vegetation management, as it relates to wildfire mitigation, refers to the total or partial removal of high fire hazard grasses, shrubs, or trees. In addition to fire hazard reduction, vegetation management has other benefits. These include increased water yields, improved habitat for wildlife, reduction of invasive exotic plant species, and open access for recreational purposes in Potrero.
METHODS OF FUEL MANAGEMENT
There are 5 wildfire mitigation methods currently being used by the Potrero 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 reduction of plant volume using grazing or browsing animals, such as goats, to hold growth back and maintain low fuel volume.
Mechanical Brush Removal
The use of mechanical equipment to reduce vegetation in an area. Equipment consists mainly of a bulldozer, in combination with a “brush crusher”, a brush rake, disk or anchor chain, which crushes or removes the vegetation.
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 for brush clearance.
The application of growth inhibitors, defoliators or killers to reduce highly flammable herbaceous or poisonous plants such as annual grasses or poison oak.
One of the ways the Potrero Fire Department helps the community with wildfire mitigation is to ensure that overgrown brush does not accumulate throughout the city, and that “defensible space” is established and maintained between urban development and the “wildland” interface.
COMPLYING WITH BRUSH CLEARING:
Clear hazards and properly remove and dispose of cuttings prior to May 1, the beginning of the Brush Clearance Inspection Sweep in Potrero. If your property fails the first inspection, a notice of non-compliance will be issued to the owner of record.
Please contact us with how to comply with Potrero Brush Clearance Requirements.