Colorado has 4 major seasons: football, skiing, road construction and fire (fall, winter, spring and summer, respectively). And since we’ve long been plagued with below average precipitation levels, diminishing snow fall leading to minimal runoff and nonexistent rain storms, plus temperature anomalies bringing warm weather earlier and earlier with each passing year, it would appear there is no respite in site. Ladies and gentlemen, it’s wildfire season.
For those of us who live in the mountains or foothills of not only Colorado but throughout the western U.S., we must vigilant in our attempts to stop a wildfire in its tracks and the best way to do that is through firescaping. A relatively new term in the field of landscaping, firescaping means creating non-burn zones around your property. If a wildfire is coming through, it’ll take what’s in its path—including houses—unless there is no path for the fire to follow. The basic idea is: the closer to your home, the less vegetation you want but the practice includes planting for fire safety, vegetation modification techniques, use of fire safety zones, and defensible space principles.
Vegetative clearance around the house (defensible space) is a primary determinant of a home’s ability to survive wildfire. Defensible space is, simply, room for firefighters to do their job. If grasses, brush, trees and other common forest fuels are removed, reduced, or modified to lessen a fire’s intensity and keep it away from the home, chances increase that the structure will survive. It is a little-known fact that in the absence of a defensible space, firefighters will often bypass a house, choosing to make their stand at a home where their safety is more assured and the chance to successfully protect the structure is greater.
TWO TYPES OF WILDFIRES
Two types of wildfires – surface and crown fires – can affect homes. Surface fires burn materials lying on or immediately above the ground including pine needles, leaves, grass, downed logs, stumps, tree limbs and low shrubs. This type of wildfire can surround a home and slowly find vulnerable spots to attack. Crown fires move through the canopy of a forest stand, burning from one treetop to the next. They can have extremely high flame lengths, which often start spot fires far ahead of the fire front.
Crown fires are the most destructive of all wildfires, able to burn mature trees and shrubs, and can move over large areas in short periods of time. Surface fires can become crown fires in stands where there are “ladder fuels” (ex: branches that extend to the ground and allow a fire to climb up a tree from branch to branch, to its crown).
THE 3 IDEAL ZONES FOR FIRESCAPING:
Zone One involves clearing a 30-foot area surrounding a house. Concrete or brick patios in this area are ideal, as well as low growing perennials and annuals. If you are mulching within this zone, it’s preferable to use inorganic materials such as crushed stones or gravel rather than more combustible options like shredded rubber, pine straw or red cedar. Composted wood chips show the slowest fire spread rate of organic mulches. Take care to arrange landscape plants so they are well spaced to prevent fire from moving from one plant to the next.
Should trees need to be planted in this first zone to provide shade, they must be deciduous, as deciduous trees have a higher moisture content in their leaves and don’t contain flammable oils. DO NOT plant evergreen trees and shrubs such as pines, junipers and cedars as they can and will burst into flame with extreme heat. Be sure to remove any branches within 15 feet of chimneys and stovepipes; also, try to maintain at least 6 feet between the branches of adjacent trees and shrubs. Avoid planting directly beneath the trees.
Zone Two or the mid-zone is the next 30 – 90 feet. This area is for orchards and gardens. Lower limbs of trees should be pruned to 15 feet off the ground.
On steep slopes, groundcover plantings, especially succulents, whose leaves are filled with water, will retard the spread of a wildfire up a hill. Mowed lawns, when green and actively growing, will also slow the spread of flames across the ground and up hillsides. We’re shooting for “lean, clean, and green”.
However, extensive areas of turf grass may not be right for everyone so consider incorporating a fuel break. Water features, pools, ponds, or streams can be fuel breaks, in addition to boulders, rocks, dry creek beds, patios, or masonry planters. While bare ground is an effective fuel break, it is not recommended as a firescape element due to soil erosion and other concerns. A bonus to opening up your landscape is that you’ll find you’ve simplified things. The breaks in vegetation can add interesting elements to the landscape and overall, it can become more peaceful and relaxing to look at and maintain.
Zone Three is no closer than 100 feet from the house. Trees need to be thinned so that crowns are separated by at least 10 feet. Prune branches up from the ground to a height of 10 feet. The goal is to keep a fire from “laddering” up from the ground. When this happens, things get out of control quickly.
Whether a site can be irrigated will greatly influence location of hardscape (concrete, asphalt, wood decks, etc.), plant selection, and placement. Prevailing winds, seasonal weather, local fire history, and characteristics of native vegetation surrounding the site are additional important considerations. A home located on a brushy site above a south- or west-facing slope will require more extensive landscape planning for defensible space than a house situated on a flat lot with little vegetation around it.
PLANT CHOICE IS KEY
When temperatures hit the 80s, 90s, and even triple digits, it’s wise to have some drought- and heat-resistant plants in your garden. Sedum, stonecrop, verbena, coneflowers, lantana, phormiums salvia and yucca all fit the bill. Easy-care, drought-tolerant shrubs include potentilla, barberry, buddleia, cotoneaster, and witch hazel. Easy-to-grow annuals that survive in drought conditions include geraniums, ageratum, calendula, snapdragons and dusty miller.
Avoid plants like large growing herbaceous ornamental grasses and other big perennials that die back to the ground in winter and leave behind combustible dried leaves and stems. (If you do plant them, you must always cut them back to just above the ground in the fall.)
WATERING AND MAINTENANCE
As summer heats up, frequent watering is the ultimate firescaping strategy. While we want to conserve this valuable resource, it can be helpful to use drip irrigation systems that are inexpensive to set up and can get water where it matters most – right at the base of plant. This curbs fungal disease by keeping water off foliage. Also, since you’re only watering the roots, you aren’t encouraging weeds.
Always keep a watchful eye towards reducing the fuel volumes available to fire. Be aware of the growth habits of the plants within your landscape and of the changes that occur throughout the seasons. Remove annuals and perennials after they have gone to seed or when the stems become overly dry. Rake up leaves and other litter as it builds up through the season. Mow or trim grasses to a low height within your defensible space. This is particularly important as grasses cure. Remove plant parts damaged by snow, wind, frost or other agents. Timely pruning is critical. It not only reduces fuel volumes but also maintains healthier plants by producing more vigorous, succulent growth.
A landscape is a dynamic system that is constantly growing and evolving. And while most often designed to be aesthetically pleasing and sensorially relaxing, it is also the most critical part of your home’s fire defense system. Making the right choices now could mean saving yourself and your family a lot of heartache, later on… Remember, an ounce of prevention is worth a pound of cure.
For more information, please reference this extremely helpful guide created by the Colorado State Forest Service • USDA – Forest Service • Bureau of Land Management • National Park Service • Bureau of Indian Affairs • US Fish and Wildlife Service : https://static.colostate.edu/client-files/csfs/pdfs/LWF51303.pdf
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