Over the last few years, it seems summers are getting hotter and fire season is extending for months longer. Living in an urban environment is not always protection against a wildfire as Santa Rosa CA and Talent OR residents learned too well and so painfully.
To design a landscape which is wildfire resistant – that is fire resistant is not fire proof because in the end everything burns — You must first, think like fire. So instead of beginning this article with a list of plants, you need to know more about how fire acts, the conditions that fuel it and strategies about how to manage it.
What is Firescaping? This is a relatively new term born from the ashes of the wildfires we have experienced over the last few years. My own definition is designing, planting and maintaining a landscape to resist a wildfire, keeping in mind that everything will ultimately burn.
Why talk about creating fire defensible landscapes in an urban environment? The famous Eagle Creek Fire in the Columbia Gorge in Sept. of 2017 was a wildfire in the wilderness. However, the Santa Rosa wildfire in California and the wildfire which burned the town of Talent Oregon to the ground were not fires in the wilderness. They were wildfires in areas called the Wildland-Urban Interface.
Residents of Santa Rosa, CA and Paradise CA and our own Overlook Neighborhood in Portland (Fire Aug. 2017) discovered even urban living environments can be at risk too. No matter if there’s a fire hydrant at the street.
In 2020 you may remember the Beechie Creek Fire which threatened Salem, Oregon, The Riverside Fire in Clackamas, Oregon, The Lionshead Fire in Jefferson County, Oregon and South Obenchain Fire which impacted Ashland, Talent and Phoenix, Oregon. Those wildfires leveled 2800 structures. There were nearly a dozen fires in all. State wide, 10 people died and 1,000,000 acres burned.
What is Wildland-Urban Interface? It is land at the edge of a wildland (neighborhoods like Oaks Bottom, Johnson Creek, Sullivan’s Gulch) or near a wild urban park (Forest Park, Mt. Tabor, Rocky Butte and Powell Butte) which could be impacted by fire as easily as in a rural area.
These areas are becoming known as the “Wildland-Urban Interface” by planners and fire professionals.
First, think like fire… basic facts:
Wildfires are dependent on 3 things --- fuel, terrain and weather.
Fuel equals combustible materials like, wood siding, cedar shakes and composition roofs, dry or dead plants and a thick understory.
Terrain like steep hillsides, ravines, any place which is difficult to reach and deeply forested or dry, wild, grassy lands.
And Weather which is a threat is low humidity and high temperatures combined with wind.
Topography has an impact on wildfires: If a property sits at the top of a hill or a bluff or a ravine, as view properties often do, it is at risk when a fire starts at the bottom of the slope because fire will race up the vertical surface.
Wind drives wildfires. Understand which direction of the prevailing winds come from in the summer and early fall, that is to say, during fire season. In the Portland area, summer winds blow out of the north-northwest and in the fall, they are typically out of from the east.
Therefore, if a property is at the edge of a Wildland-Urban Interface, downwind and at the top of a slope that property is seriously at risk.
Landscape Design Considerations:
What determines a fire resistant vs. fire risky plant?
A Low risk plant is one which has high moisture content in the leaves, thick broad leaves, and an open growth habit (not compact and dense). And low risk plants are plants which are well maintained with no dead plant material.
A High risk plant is one which has a high oil or high resin content in the leaf or bark, a dense structure, low leaf moisture content, a presence of dead material, a chemical content in the sap and peeling bark.
Generally speaking, deciduous trees and plants are less flammable than conifers.
Examples of some highly flammable and common plants include:
Some of the Cypresses
Bamboo because of its dry, papery leaves.
Tall grasses like Maiden Grass – if not cut back when dry.
Planting Strategies for wildfire resistance.
Space larger plants (Shrubs and Trees) apart so fire cannot jump from canopy to canopy. The spacing is dependent upon the mature size and growing habit of the plant. You can take clues from nature to understand the spacing of different varieties.
Maintenance: Think… what does fire “eat”? And give it NO fuel.
Limb up conifers (Doug Fir, Cedar, Hemlock, Pine, etc.) 10’- 15’ from grade and closer to 20’ above the ground with very tall trees. Low hanging branches, tall shrubs and dry grasses create fuel ladders. Trim up branches which overhang a roof or a deck (wood or composition materials).
Keep gutters and roofs free of debris and needles. And mow meadows in the dry months or irrigate.
Well-watered landscapes are more fire-resistant than dry plantings. If you have a lawn, keep it watered and mowed in the dry months.
Removing invasives is important – Himalayan Blackberry, Ivy, Scotch Broom. All of these plants create dense thickets and provide available fast-food for a fire. Think of a McDonalds or the Taco Bell Drive through.
Do basic, ongoing maintenance – remove dead or dying trees, fallen limbs after storms and blackberry thickets.
With large properties “fire Sprinklers” can be designed in to the landscape as part of the irrigation system at the perimeter of the property which allows owner to quickly drench the perimeter when needed. Some sprinkler systems can be operated remotely from your phone so a vacation home can be protected even if vacant.
Lastly – Be One with your neighbors
Remember a property is only as defensible as the Neighbor’s property next door. Encourage neighbors to follow the same protocol as you do so one neighbor does not put all at risk.
Share the load and help to maintain everyone’s properties. Perhaps organize spring and fall clean up parties and make the work fun!
Remember…No one is an island…especially in a wildfire.