Tree services have an important role to play in fire prevention, particularly in the American West. Climate change is making forest areas warmer and drier and drought more frequent, increasing the hazard of wildfire. The US Forest Service is promoting an integrated approach to community preparedness, involving forward planning, hazardous fuels reduction inside and near communities on public and private lands, and the adoption of fire-resilient building codes that will better protect structures from ignition by embers, the primary cause of structure loss.
While state and federal agencies have the responsibility for public lands, private tree services will be most helpful to communities and private homeowners in doing the hazardous fuels reduction work near and within communities. Owners of tree service companies might even consider positioning themselves as experts in “fire hardening,” the process of making a property less susceptible to ignition by embers.
Over the last few decades many people moved into rural areas outside of towns, particularly where the surrounding land is scenic, either forested or mountainous (often both). These areas often lack fire hydrants and are some distance from fire stations, creating a dangerous situation. According to the Forest Service, over the last 10 years, more than 35,000 structures were destroyed by wildfires, an average of 3500 per year. It is therefore very important for homeowners to prepare their properties through fire prevention tactics. There has been mixed success with this as it can be expensive. However, insurance companies sometimes require proof of defensible space clearing in order to insure a building. A tree service owner might educate themselves on cost-sharing programs and pass this information along to homeowners.
Creating Defensible Space Close to a Structure
A wildfire burns when heat, fuel, and a source of ignition are all available. Defensible space creation means reducing the amount of fuels near structures. The area surrounding a structure can be divided into three zones. The immediate zone, from 0 to 5’ from a house, receives the most intense treatment. Remove all dead vegetation including leaves and pine needles as well as any branches from trees that overhang a structure, and remove any trees whose canopy will be within 10 feet of a structure’s roof at maturity. Trim trees to keep branches from neighboring trees from touching. Remove vegetation from under large stationary propane tanks.
Creating Defensible Space Further From a Structure
In the intermediate zone between 5’ and 30’ from a structure, remove all dead trees and branches, and create horizontal and vertical spacing between living lawns, bushes and trees. Remove the branches of trees up to a height of at least 6 feet (for trees shorter than 6 feet remove branches up to one-third of the tree’s total height). An important problem in fire spread is the “fire ladder.” Fires can spread across the ground via fallen leaves, dead grass, etc. Once the fire reaches a taller plant, it can ignite the plant and climb, and if that plant is located near a tree with dead lower branches, the fire can spread into the tree. Breaking these fire ladders is an important part of fire prevention. How far apart you should space plants and trees depends on the slope of the land and the size of vegetation as fire spreads more quickly as it burns up a steep slope.
In the extended zone beyond 30’ and up to 100’ from a structure, the goal is not to eliminate fire, but to keep it low. To do this, dispose of heavy accumulations of ground litter/debris and remove any dead plant and tree material. Remove small conifers growing between mature trees, and remove any vegetation that is close to outbuildings.
As a tree professional you can recommend fire-resistant landscaping. This type of landscaping has low, fire-resistant plants that are placed to resist the spread of fire to a house, stone walls, patios, non-combustible mulches and gravel areas. Some good plant choices include hardwood trees, including fruit trees, rather than pine, cedar, or other conifers. Low plants with high moisture content such as iceplant and aloe are also good choices, particularly if they are also drought-resistant.
Certain plants are known to be quite flammable (“pyrophilic/pyrophytic”), such as the introduced species Scotch broom and resinous species like pines and junipers. Advise homeowners that these should be removed or kept at a distance from a house.
Tree professionals should trim trees along driveways so firefighting equipment can easily enter and exit. A driveway or road should be at least 20 feet wide through its entire length. A good objective is to make it possible for fire truck drivers to see the house beyond so they can be sure they will not become trapped.
A property that is located on a steep slope, in a drainage, in a windy area or an area surrounded by tall, dense, and/or combustible vegetation should be thinned in the area beyond the 100’ zone. Areas with an active fire history (a good example is Malibu) or that are naturally a chaparral (a fire-prone brushy area generally on south- or west-facing slopes) need greater spacing between trees/plants. Often homeowners seek to capitalize on views by building homes at the top of such a slope; this magnifies the fire hazard because fire and heat rise, leading to pre-heating of the upslope fuels. In such cases fuels downslope of the home should be aggressively removed and vegetation very well spaced. In these areas tree canopies should be separated by at least 18 feet; more is better.
The good news is that these efforts do pay off for homeowners. Case studies document defensible space making the difference in saving structures from deadly wildfires such as the Camp Fire of 2018, which destroyed the town of Paradise, CA. A home with good defensible space is seen by firefighters as worth fighting for. With wildfire an inevitable fact of life in the West, tree professionals have their work cut out for them.
Providing your clients with fire prevention services, still carries its share of risk for your tree service business. Learn how TreePro can help safeguard your investment.