Defensible Space

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CalFire-Defensible-Space-ZonesCreating and maintaining defensible space is essential for increasing your homes chance of surviving a wildfire. It is the buffer that homeowners are required to maintain on their property between a structure and the plants, brush and trees or other items surrounding the structure that could catch fire. This space is needed to slow the spread of wildfire and improves the safety of firefighters defending your home.

How the 100 feet of defensible space is maintained is dependent on the vegetation present, the topography, and the proximity of nearby buildings. There is no universal specific standard for maintaining defensible space that works for every property. Instead, the hazardous vegetation on a property should be maintained based on the conditions present and to achieve the ultimate goal of the VMP, to reduce the risk of building ignition during a wildfire.

Zone1_Zone2

 

Below are general guidelines for creating defensible space around a building and can also be found in our VMP Brochure and the VMP Defensible Space Guidelines.

The Glendale Fire Department separates the 100-foot defensible space area into two zones: Zone 1 begins at the outside wall of a building, a deck, or other structure and extends 30 feet; Zone 2 begins at 30 feet from the building and extends to 100 feet from the building.

These zones are useful for organizing vegetation maintenance activities on a property but the recommended practices are beneficial wherever they are used.

 

Zone 1 Activities - Extends 30 feet out from buildings, decks, and other structures

  • Remove all dead plants, grass and weeds.
  • Remove dead or dry leaves and pine needles from your yard, roof and rain gutters.
  • Trim trees regularly to keep branches a minimum of 10 feet from other trees.
  • Remove dead branches that hang over your roof, and keep branches 10 feet away from your chimney.
  • Remove or prune flammable plants and shrubs near windows.
  • Remove vegetation and items that could catch fire from around and under decks.

Zone 2 Activities - Extends 30 to 100 feet out from buildings, decks, and other structures

  • Cut or mow annual grass down to a maximum height of 4 inches.
  • Create a minimum horizontal spacing of 20 feet between shrubs and trees.
  • Create a minimum vertical spacing of 6 feet between grass, shrubs and the lowest branches on a tree.
  • Remove fallen leaves, needles, twigs, bark, cones, and small branches. However, they may be permitted to a depth of 4 inches if erosion control is an issue.
  • Protect water quality. Do not clear vegetation near waterways to bare soil. Excessive clearing can cause soil erosion.

General VMP Defensible Space Guidelines

Defensible Space around Buildings (0 to 100 feet from the building)

  1. Cut vegetation should be disposed of properly. Piled cut vegetation whether grass, shrub, or woody branches creates a special fire hazard regardless of its proximity to a building.
  2. Dead bushes, shrubs, and trees should be removed.
  3. Firewood should not be stored beneath a deck, within 30 feet of a building, or beneath large shrubs and trees Vegetation surrounding firewood piles should be well maintained and not likely to carry fire into the pile.
  4. Particular attention should be given to the maintenance of vegetation and the storage of combustible materials beneath wooden decks and wood piers.
  5. Steep slopes, large cut banks, fragile slopes, and loose soil are all common in Glendale’s High and Very High Fire Hazard Area. Some Vegetation, including scattered larger plants, should remain on all hillsides after maintenance work is complete.
  6. The roof should be free of accumulations of leaf litter, needle cast, and fallen branches. Roof surfaces do not need to be 100% clean of leaf litter.
  7. Gutters, balconies, alcoves, and other recesses where accumulations of leaf litter, needle cast, and fallen branches can build up, should be cleaned out.
  8. Bushes, shrubs, and trees immediately adjacent to a building should be trimmed to remove dead branches. Particular attention should be given to bushes and trees with large, continuous areas of dead branches.
  9. It is extremely common in Glendale for landscape bushes, shrubs, and trees to be planted within five feet of a building. This results in branches that are in contact with the sides and roof of the nearby building. These bushes, shrubs, and trees can be retained providing the following conditions are met:
    • The vegetation is healthy and well maintained. The vegetation should be green and free of accumulations of dead branches or leaves.
    • Leaf litter is not allowed to accumulate on or near the building.
    • Good vertical clearance is maintained between the vegetation on the ground and lowest branches on the bush, shrub, or tree. The surrounding vegetation on the ground should be maintained. Grass, shrubs, and other ground cover should be cut and green. Bushes and shrubs beneath large trees should be maintained to the same standards described above.
    • Trees and large shrubs should be trimmed so that no branches are resting on the roof surface. Particular attention should be given to vegetation with a large amount of branches in contact with the roof and with species known to produce a lot of litter.
  10. Remove dead vegetation. Particular attention should be given to bushes, shrubs, and trees that still retain a large complement of brown/dead leaves.
  11. Remove the dead fronds and flowers from palm trees. Particular attention should be given to palm trees that have not been trimmed for more than five years, palm trees immediately adjacent to a home, or palm trees immediately adjacent to high voltage electrical equipment.
  12. Annual grass, weeds, non-woody shrubs, and other ground cover should be cut to 4 inches or less.
  13. Retained bushes and shrubs should be healthy without leaf litter or deadwood accumulations within or beneath the plant.
  14. Large areas of dense brush and trees should be separated into well-spaced individual plants with open space between individual plants. Twenty feet of horizontal space between each plant is preferred.
    • Continuous rows of ornamental bushes, shrubs, and trees are common landscaping elements in Glendale. Rows of green, healthy, and well maintained vegetation should not be considered a fire hazard provided their current condition would not increase the severity of a nearby fire.
  15. The lower branches of trees should be trimmed so there is open vertical space between the ground and the lowest tree branches. Six feet of open space is preferred but the size of the tree, the slope of the terrain, and the size of the vegetation below should be considered.
    • Small trees should not have more than ½ of their live crowns removed.
    • On steeper slopes, larger trees should have more than six feet of open space between the lowest branch and ground
    • When there are bushes and shrubs beneath a tree, consider removing them rather than only trimming the lower branches off the tree.

Roads (0 to 10 feet from the paved surfaced)

  1. Vegetation alongside a road should be maintained to allow access for emergency response vehicles and to minimize fire intensity near the road. Vegetation should be maintained from the edge of the curb, pavement, or sidewalk to 10 feet onto the property.
    • Vegetation alongside a road should be maintained regardless of how close the nearest building is.
    • Particular attention should be given to the vegetation along public streets and shared driveways.
  2. Cut tall grass, weeds, and non-woody shrubs within 10 feet of the road to 4 inches in height or less. Particular attention should be given to vegetation growing along the edge of and overhanging the curb or the edge of the pavement
  3. There should be 14 feet of vertical space above the roadway and eight feet of vertical space above a sidewalk or parking area. Branches from trees, bushes, and shrubs that extend over the roadway and into the required clearance area above, should trimmed back to the edge of the pavement, curb, or sidewalk.
  4. Dead vegetation within 10 feet of road should be removed.

Extended Distances (100 to 200 feet from the nearest building)

In areas where a specific extreme fire hazard exists, the Fire Department can require additional hazardous vegetation maintenance, up to 200 feet from the nearest building. The decision to require extended clearance distances should be based on mitigating a specific hazard and done with the approval of the Fire Marshal.

  1. Particular attention should be given when declaring properties require extended clearance distances.
    • The extended distance should not be applied to a location where a wildfire could easily bypass or burn around the treated area (e.g. one side of drainage or a portion of a slope).
    • Preferably properties where extended distances are required should connect two existing barriers to fire spread (e.g. a road or rocky outcropping) or should connect to existing treated areas.
  2. Annual grass, weeds, non-woody shrubs, and other ground cover should be cut to 4 inches or less.
  3. Large areas of dense brush and trees should be separated into well-spaced individual bushes, shrubs, and trees with open space between each individual plant. Twenty feet of horizontal space between each island is preferred.
  4. The lower branches of trees should be trimmed so there is open vertical space between the ground and the lowest tree branches. Six feet of open space is preferred but the size of the tree, the slope of the terrain, and the size of the vegetation below should be considered.
  5. Dead bushes and trees should be removed. Piles of dead vegetation should be removed or scattered.
  6. When removing cut vegetation from a property is not feasible (e.g. no road access), cut vegetation may be scattered on the ground on the property. Since the cut vegetation will readily burn during a wildfire; scattered vegetation should be spread out so that when it burns it does not magnify the severity of a fire, allow the fire to cross a natural or man-made barrier, or spread into the crowns of nearby bushes and trees.