The last 10 years has brought unprecedented attention to reducing fire risk of homes in the wildland interface. Stimulated by an infusion of federal funding, many communities in Idaho have organized concerted efforts to reduce these fire risks. Many people have heeded forest fire warnings and removed fuel ladders between their home and landscape and between trees in the surrounding landscape. However, it is a mistake to relax in subsequent years . . .

Nature abhors a vacuum. Creating more spaces between trees means more light will reach the forest floor. There will also be more moisture and nutrients available for plant growth. All of this means remaining understory plants and trees will grow larger and faster (especially younger trees) and new plants have a more favorable environment to germinate and grow. To maintain a fire-resistive landscape, plants and plant litter must be continually monitored and modified or removed as needed.

Plant litter around structures. Fuels for a fire and other factors closest to the home usually have the greatest influence on whether a home burns down in a forest fire. Pay extra attention to flammable materials that contact the house. Continue keeping the roof, gutters, and foundation of the house cleaned of needles and other debris.

Trees. If trees have just a few branches within 10 feet of each other, prune them back. If adjacent trees have many branches crowding together, it may be time to thin out a few more trees. This will also improve the health of the remaining trees. Cut seedlings periodically as they emerge in the understory.

Grass. A green turf is very fire resistive, so if possible, keep your lawn well-watered through the summer. Longer watering cycles – 1-1.5" of water per week in 1-2 waterings will maintain a healthy sod for most soils. If you cannot keep the grass watered, keep it trimmed low, especially close to the house. At the edge of your landscape, establishing a low-maintenance, low-growing grass, such as sheep fescue or hard fescue (both of which are very competitive) will help reduce new tree or shrub establishment.

Brush.

Mechanical control. Fuel hazard from shrubs can be reduced by cutting plants off at the base. However, such shrubs frequently re-sprout vigorously from latent buds in the root crown (an adaptation to top removal by fire), especially on stems smaller than 2 inches thick. Repeated trimming is usually necessary to maintain reduced fire risk. Mid-summer is the best time to do this.

Depending on the job, a variety of tools can be used for mechanical control, ranging from loppers and pruning shears on smaller jobs, to chainsaws or clearing saws for multiple stems or stems larger than 1 inch. For smaller diameter stems, brush mowers, brush hogs, or similar devices may be used.

Mulch. Mulch can help suppress understory plants but remember; bark, wood chips, and other organic materials will burn -- keep them away from the base of structures (use rock or other non-flammable material instead). Do not make the mulch deeper than one inch, to avoid interference with root activity and tree health.

Livestock. Sheep or goats may also help suppress brush. Time grazing to late spring or early summer (not early spring) to minimize soil impacts. Later grazing also reduces plants’ ability to regenerate because of drier soils.

Herbicides. Herbicides control brush species efficiently, and if label directions are followed, the effects on other forest values (beyond removing the brush) are negligible. There are many methods of killing brush with herbicides, but the most common for landscape maintenance are stump treatments, basal bark treatments, and foliage treatments.

Stump treatments. You can effectively reduce sprouting by immediately (within an hour) applying a very small amount of undiluted herbicide to the perimeter of freshly cut stump surfaces. Immediate application is important; otherwise the plant quickly develops a protective wax layer over the wound.

Basal bark treatments. Some herbicides can be applied directly to the stems at the base of the plant. These applications usually require a specific additive (described on the herbicide label). They may be applied either during either the growing season or dormant season. For example, both "Banvel" and "Forestry Garlon 4" labels have dormant stem treatments for small diameter brush. Brush would still have to be cut and removed after killing it to maintain fire resistance.

Foliar treatments. Foliar sprays involve treating the whole plant after it is fully leafed out. Timing varies according to the herbicide used, and is important to make sure the herbicide is moved by the plant into the roots to minimize re-sprouting. Avoid applying the herbicide until the spray drips off the plant, since this indicates you are applying more herbicide than necessary. Again, brush would still have to be cut and removed after killing it to maintain fire resistance.

Herbicide Products. Several herbicide brands are sold to kill brush. Brush control herbicides available in local home & garden stores frequently include triclopyr (e.g., "Blackberry and Brush killer", "Brush-B-Gon") or glyphosate (e.g., "Round-up").

Brush control herbicides targeted to larger forest owners or commercial contractors for forest use are often packaged differently (e.g, in larger containers) and may have to be specially ordered. These herbicides include: imazpyr (e.g., "Arsenal"), glyphosate (e.g., "Accord"), 2,4-D, triclopyr (e.g., "Garlon"), picloram (e.g., "Tordon"), dicamba ("Banvel" or "Clarity"), or combinations of these (e.g., 2,4-D and triclopyr in "Crossbow"). Some of these herbicides have specific state regulations such as requiring an applicator’s license and restrictions on how close they can be applied to a home. The herbicide labels will list plants controlled by the herbicide.

Regardless of the herbicide, always read and precisely follow the label recommendations before purchasing and using it. For current recommendations for specific brush species, consult the Pacific Northwest ("PNW") Weed Management Handbook, which is updated annually by Pacific Northwest Land Grant Universities and available online at: http://weeds.ippc.orst.edu/pnw/weeds.

Maintenance not later; now. You never know whether this year will be the big fire season for your neighborhood. By maintaining a fire resistive home and landscape, you are always prepared for that fire.

Thanks to Tim Link, UI Extension Specialist in Weed Ecology, for his contributions to this article.

 

 

For additional information and informative figures and photos, email the UI Extension Forestry office and request a copy of Protecting and Landscaping Homes on the Wildland Urban Interface. by Yvonne C. Barkley, Chris Schnepf, and Jack Cohen. Station Bulletin No. 67, January, 2005. Idaho Forest, Wildlife and Range Experiment Station, Moscow, ID.