18E.40.070 – Appendix F Wildfire – Defensible Space Guidelines
Brush Thinning GuidelinesRecommended brush thinning varies upon the slope of the ground and the height of the existing vegetation.
|
Slope of Ground |
Recommended Spacing |
Example |
|---|---|---|
|
0 – 20% |
2 X the height of the brush |
Shrubs that are 3 feet high on average should be thinned to be 6 feet apart. |
|
21 – 40% |
4 X the height of the brush |
|
|
41% + |
6 X the height of the brush |
Ladder Fuel Separation GuidelinesThe recommended vertical separation distance between shrubs and adjacent trees is 3X the height of the shrub. As an example, if shrubs 6 feet in height are located below a tree, it is recommended that the tree limbs be removed to a height of 18 feet.
|
Fire Resistant Plants |
|||
|---|---|---|---|
|
Tree |
Shrub |
Shrub |
Ferns |
|
Acer macrophylum |
Acer circinatum |
Ribes spp. |
Adiantum pedatum |
|
Alnus rubra |
Arctostaphylos uva-ursi |
Rosa spp. |
Athyrium felix-femina |
|
Betula ssp. |
Amelanchier alnifolia |
Sambucus racemosa |
Blechnum spicant |
|
Cornus spp. |
Cladothamnus pyrolif |
Sheperdia Canadensis |
Cystopteris fragilis |
|
Fraxinus latifolia |
Ceanothus velutinous |
Sorbus sitchensis |
Dryopteris expansa |
|
Malus spp. |
Ceanothus sanguineus |
Vaccinium spp. |
Gymnocarpium dryopteris |
|
Populus spp. |
Cornus stolonifera |
Viburnum edule |
Polypodium glycyrrhiza |
|
Prunus spp. |
Corylus cornuta |
Rhamnus purshiana |
Polystichum munitum |
|
Quercus spp. |
Crataegus douglasii |
Rhododendron spp. |
Thelypteris phegopteris |
|
Salix spp. |
Gaultheria shallon |
Menziesia ferruginea |
|
|
Gaultheria ovatifolia |
Myrica gale |
||
|
Holodiscus discolor |
Oemleria cerasiformis |
||
|
Linnaea borealis |
Oplopanax horridus |
||
|
Lonicera ciliosa |
Pachistima myrsinites |
||
|
Lonicera involucrata |
Philadelphus spp. |
||
|
Mahonia spp. |
|||
(Ord. 2013-45s4 § 4 (part), 2015; Ord. 2009-18s3 § 4 (part), 2009)