Tending Trees in Fire-Prone Areas


The distances between trees significantly affects the extent of the damage incurred. Photo Credit: NASA

No matter how natural recurrent fires are, it is hard to appreciate Mother Nature’s majesty while watching your worldly belongings burn to a crisp.

Do not wait idly while politicians and professors debate policies for managing wildfires; instead, take proactive steps to help protect your home and family.

In addition to keeping potential fuels at least 30 feet away from your home, you can employ several strategies that will confer some protection on the trees in your yard. Although it is impossible to shield your home from catastrophic fires, a few techniques and strategies can greatly improve the chances that your trees – and therefore your home – emerge from low-intensity fires unscathed.

Crown Control

Crown raising is the process of removing the lowest limbs of a tree. Although often carried out for aesthetic or logistic reasons (such as to allow access under the tree or improve sight lines), crown raising can help reduce the tree’s risk to fire, as ground-traveling fires will have fewer opportunities to climb into the tree’s crown. For best results, the University of California, Division of Agriculture and Natural Resources, advises homeowners to raise all crowns a minimum of 15 to 20 feet above the ground. (Glenn Nader, 2007) While the removal of a tree’s bottom limbs may not save it from a high-intensity fire, the lack of bottom limbs may prevent a low-intensity, surface fire from climbing up to the tree’s canopy. It is important to have an ISA-certified arborist perform such tasks, as crown-raising procedures alter the way that trees respond to wind.

Clean the Crowns Regularly

To clean a tree’s crown, arborists remove all of the dead and troublesome branches from the crown. This not only helps to protect the tree from pests and infection, but it helps reduce the amount of fuel in the canopy, which reduces the tree’s risk to fire. Additionally, dead branches represent a safety hazard, and should always be removed when they occur over people or property. Additionally, always be sure to have branches near your home trimmed back at least 10 feet from the roofline and chimney, which will reduce the paths by which the fire can reach your home.

Plant Fire-Resistant Species

Given the right conditions, all plants will burn. However, some trees are more resistant to fire than others are. Whenever possible, use such species around homes and buildings to help reduce the overall risk of fire. In general, broadleaf, deciduous species are superior to evergreen conifers because their leaves (when present) contain more moisture, and they often lack oily and waxy substances, which are often highly flammable. Horse chestnuts (Aesculus hippocastanum), redbuds (Cercis canadensis), red alder (Alnus rubra), flowering dogwoods (Cornus floridana), river birches (Betula nigra) and many maples (Acer sp.); make excellent choices for fire-prone areas. (Pacific Northwest Extension, 2006) While many of these species are not native to the state, they have a relatively low potential for becoming invasive.

Space Trees Appropriately

Because fire uses branches and vegetation to travel from one tree or plant to the next, tightly clustered trees and shrubs are more susceptible to fire than isolated specimens are. Accordingly, it is important to space your trees well to provide them with the greatest chance of emerging from the fire intact. Pay attention to the spacing between not only the trunks of trees, but – more importantly –  consider the spacing of their canopies. In addition to spacing the trees in the horizontal plane, it is important to space trees and plants vertically as well. For example, a group of shrubs directly under the canopy of a tree may allow the branches of the tree to catch fire as embers rise from the flaming shrubs.

Be Careful with Mulch

While mulch is an important tool for tree care (particularly in drought-prone regions), it represents a fire hazard. Fortunately, many different types of mulch exist, so you can select a variety that is not as likely to burn as some others are. Rocks, gravel and other inorganic mulches will not ignite, yet they will still prevent the soil from drying near the plants roots, so they make excellent choices. By contrast, many organic mulches represent a serious fire hazard. According to a study conducted by the University of Nevada, Cooperative Extension, pine needles, shredded cedar bark and shredded rubber are the most dangerous types of mulch for fire-prone areas. (University of Nevada, Cooperative Extension, 2011)


Glenn Nader, G. N. (2007). Home Landscaping for Fire. University of California, Davis.

Pacific Northwest Extension. (2006). Fire-Resistant Plants for Home Landscapes. Pacifi c Northwest Extension.

University of Nevada, Cooperative Extension. (2011). The Combustibility of Landscape Mulches. University of Nevada Cooperative Extension.