Building a structure in such proximity to oak and pine forests greatly increases the home’s exposure to wildfire. Placing a home near the top of a hill places it in the most likely path of a wildfire and where it will burn with the greatest intensity. A hilltop location also makes the grade of the driveway the steepest and, oftentimes, where it is farthest from the road. All these factors place many homes at significant risk from wildfire.
The elements of a wildfire mitigation inspection are subjective and dependent on site-specific conditions. Many people think creating defensible space always means the removal of all fuels (trees and brush) near the home, sometimes within 30 feet. This is not usually the case.
Even though Douglas County requires flammable material to be removed from the immediate area ( 15 feet) around the home, usually the focus is on a reduction of the fuels instead of total removal. The factors that determine the amount of fuel modification are type and density of fuels, building materials used, access issues (length of the driveway, distance to fire department), proximity of water supplies, and topography. All these elements will affect the amount of thinning or fuel modification the Building Division requires.
Some of the things the Building Division most typically requires within the minimum defensible space of the house are:
Removal of all dead and dying trees.
Creating 10-foot crown spacing between remaining trees, small clumps or groups of trees.
Removal of limbs on remaining trees to 10 feet above the ground.
Removal of scrub oak and smaller trees from inside the trees’ drip-line (these are ladder fuels).
Thinning scrub oak to 3 to 5-foot stem spacing.
Removal of oak limbs to 2 to 3 feet above ground.
Another important point to be aware of is the end result of creating a defensible space: the risks to your home from wildfire are reducedbut not eliminated. The typical goal of wildfire mitigation on a specific property is to lessen the chances of a ground fire getting to the crowns; reduce fire intensity if it is in the crowns when it gets to the property; and to lower the chances of a fire starting in the home and moving to the surrounding vegetation and starting a wildfire. Good defensible space also provides suppression crews room in which to work should your home require protection.
In extreme fire danger conditions (high winds, low relative humidity, long-term drought), such as the conditions during the Hayman fire, a property that has normal defensible space still is in significant danger. Just like other ownership issues such as painting or fixing broken windows, the responsibility for maintaining the D-Space is the homeowners.
Occasionally some confusion arises about the terms used in describing our requirements to builders and homeowners. Here are the definitions of some of the commonly used terms.
Crown spacing: the distance between the branches of two or more trees. If a squirrel had to jump two feet to get from one tree to the next there are 2 feet of crown spacing.
Stem spacing: the distance between the stems, or the trunks, of two trees or bushes.
Dripline: a tree’s drip line is the same as the drip line on a house; it is where the rain drips off the limbs at the outer edge of the crown. If you are standing under a tree and can see limbs when you look straight up, you’re not to the drip line yet.
Ladder fuels: smaller plants, either brush or sapling-sized trees, that allow a ground fire to reach up and burn in the crowns of larger trees. A crown fire usually cannot be stopped regardless of the personnel or the equipment available. A tree whose crown has burned almost certainly will not survive.
Examples of ladder fuels are found almost everywhere in Douglas County. Flames snaking along the ground would feed on the shrubs. The resulting flames from the shrubs would easily ignite the crowns of the trees above them.
Douglas County is a beautiful area with great scenery and natural resources. The Building Division’s wildfire mitigation program is geared to protect life, property, infrastructure improvements, and natural resources.
Keep in mind that fires can burn from the outside to a home, but can also start in a home and burn to the outside endangering the surrounding forest and other residents’ homes. Good defensible space will help protect your home in either case.
Wildfire Hazard Regulation for Building and Development –Douglas County Wildfire Mitigation staff seeks to reduce Wildfire hazard through the development review process and implementation of our adopted regulations stated in the Douglas County Zoning Resolution Section 17. This process ensures that all new development in Douglas County is carefully assessed for wildfire hazards by our Wildfire Mitigation Specialists. If staff identifies a significant wildfire hazard a Wildfire Mitigation or Forest Management Plan is required to be submitted by a professional forester, reviewed and approved by Douglas County staff and executed prior to the issuance of building permits within the development.
Another method of addressing wildfire hazard is on an individual lot or parcel basis. Each construction project permitted through the Building Division within the Wildfire Hazard Overlay District (Wildfire Hazard District Overlay Map) is subject to the adopted regulations. Similar to the development scale process, if staff determines a wildfire hazard exists, treatment is required in the form of Defensible Space prior to the issuance of a Certificate of Occupancy. However, rather than the applicant consulting a professional forester, the Wildfire Mitigation staff provides the treatment prescription to be implemented.
Access and Wildfire Hazard Assessment – Prior to the issuance of a building permit, properties are evaluated for driveway access requirements (see Douglas County Driveway Regulations and Policies), building site location, building materials, and defensible space/wildfire mitigation requirements. When an application for a driveway permit is submitted, the address for the property must be posted; and the centerline of the driveway and the corners of the home site must be staked. This should be completed within 24 hours of submitting the application. Failure to post and stake the property will delay the processing of the permit application. In areas where driveway permits are not required but wildfire hazards do exist, structures are evaluated for location and defensible space requirements. If your project is determined to be in a wildfire hazard area as determined by an on-site assessment by the wildfire mitigation staff, a $120.00 fee will be assessed to the permit fee for the required inspections. Both preliminary and final inspections are completed prior to receiving a Certificate of Occupancy (CO).
Driveway Permits For Existing Structures –Driveway permits are required on existing residential structures for work in the County right-of-way such as paving an existing gravel drive.