Haw. Code R. § tit. 13, subtit. 1, ch. 5, exh. 5
August 12, 2011
Design standards for creation and maintenance of fire buffer zones along the urban/conservation interface. Fire buffer zones shall be approved via site plan approval.
PURPOSE The goal of a fire buffer zone is to reduce the risk of fire spreading to an area, and to reduce the speed at which fire spreads, should one occur. This is accomplished by (1) reducing the amount of available fuels, (2) reducing the continuity of available fuels, both horizontally through the proper spacing of trees and shrubs, and vertically by removing the ladder of fuels that can carry fire from the surface to the tree crowns, (3) developing a high-canopy forest, (4) replacing highly-flammable flora with drought and fire resistant indigenous, endemic, or Polynesian-introduced species, and (5) encouraging community stewardship of lands in the Conservation District.
APPLICATION REQUIREMENTS
* Parcel is considered a high-risk fire prone area by an authority recognized by the department (e.g., Division of Forestry and Wildlife, or the County Fire Department).
* If landscaping is to occur on neighboring parcels, the applicant should have permission of the neighboring landowner. The chairperson may sign as landowner for parcels owned by the State.
* A Site Plan should include three elements:
* Maps for the area should identify: topography, drainage patterns, land ownership, dominant flora and fauna, trees greater than ten inches in diameter measured at 4.5 feet above the ground, endangered and threatened trees, and other indigenous, endemic, or Polynesian-introduced trees or shrubs, infrastructure, and known historical or archaeological sites.
* The implementation plan should show the final design of the fire protection zone, how impacts to endangered or threatened trees or shrubs, or historical or archaeological sites will be mitigated.
* The management plan should discuss how and when the fire protection zone will be maintained.
* The size of the fire buffer zone will be based upon the slope of the area, as shown in Table 2. Distances are measured from the outside of the main structure, as measured from the outside eaves and/or any attached structures.
TABLE 2: AREA OF DEFENSIBLE SPACE | ||
ZONE | SLOPE | DEFENSIBLE SPACE |
1 Area of maximum reduction | all | 0-15 feet |
2 Area of fuel reduction | 0-20% | 15-30 feet |
21-40% | 15-50 feet | |
[GREATER THAN]40% | 15-70 feet | |
3 Transition Zone | 0-20% | 30-75 feet |
21-40% | 50-100 feet | |
[GREATER THAN]40% | 70-125 feet | |
DESIGN ELEMENTS
The following are acceptable design elements for each zone:
Zone 1:
* Removal of all flammable vegetation.
* Pruning of existing trees to a height of ten feet above the ground or to one-half the height of the tree, whichever is the lowest.
* Planting of drought and fire resistant indigenous, endemic, or Polynesian-introduced trees and shrubs, along with associated soil improvements and mulching.
* Removal of all ladder fuels beneath existing trees.
Zone 2:
* Thinning of trees and shrubs so that they stand solo, or in clumps of two or three. Recommended space between crowns is based upon slope, as summarized in Table 3.
TABLE 3: MINIMUM TREE AND SHRUB SPACING FOR ZONE 2 | ||
SLOPE | TREE CROWN SPACING | SHRUB CLUMP SPACING |
0-10% | 10 feet | 21/2 x shrub height |
11-20% | 15 feet | 3x shrub height |
21-40% | 20 feet | 4x shrub height |
[GREATER THAN]40% | 30 feet | 6x shrub height |
* Removal of ladder fuels.
* Mowing or cutting grasses as needed to keep them at a maximum height of 6-8 inches.
* Pruning of tree branches to a height of at least ten feet.
* Replanting of drought and fire resistant indigenous, endemic or Polynesian-introduced trees and shrubs, along with associated soil improvements and mulching.
* Removal of dead trees.
* Annual maintenance thinning of trees as they grow in size.
* Annual removal of dead stems and branches.
Zone 3:
* Thinning of trees, with spacing based upon the tree diameter measured at 4.5 foot above the ground, as outlined in Table 4.
TABLE 4: MINIMUM TREE SPACING FOR ZONE 3
Tree Diameter (inches) | Average Stem Spacing (feet) |
3 | 10 |
4 | 11 |
5 | 12 |
6 | 13 |
7 | 14 |
8 | 15 |
9 | 16 |
10 | 17 |
11 | 19 |
12 | 21 |
13 | 23 |
14 | 24 |
15 | 26 |
16 | 28 |
17 | 29 |
18 | 31 |
19 | 33 |
20 | 35 |
21 | 36 |
22 | 38 |
23 | 40 |
24 | 42 |
* Pruning of tree branches to a height of at least ten feet along fire or access roads.
* Annual maintenance thinning as trees grow in size.
MAINTENANCE GUIDELINES
Zones 2 and 3 are subject to the following maintenance guidelines:
* Any replanting should only be done with indigenous, endemic, or Polynesian-introduced trees and shrubs.
* No grubbing or grading is allowed for this land use.
* Slash (limbs, branches, and other woody debris) should be disposed of by removing it from site, chipping and distributing over the ground, or lopping and scattering.
* Tree stumps should remain in the ground.
* Surface (drip) irrigation lines are allowed to support new plantings.
* Applicant should provide the Office of Conservation and Coastal Lands with photographs of completed work.
Haw. Code R. tit. 13, subtit. 1, ch. 5, exh. 5