How to Manage a Landscape After Fire

By JoAnne Skelly

Extension Educator, Carson City/Storey County

University of Nevada Cooperative Extension

The Caughlin Fire has raised many questions from homeowners on how to save their landscapes. People want to know how to tell if their trees are alive or whether they can be saved. They want to know what to do first and whether they should prune now.

Fire damages trees or shrubs in a number of ways:

• Trunk or branch damage
• Inner tissue injury
• Leaf or needle scorch
• Bud death
• Root damage

Since the Caughlin fire occurred when trees are entering dormancy, trees may be more likely to survive. It will depend on fire intensity and length of exposure to the tree. Thickness of bark also influences survival. Chemical content is another factor. Evergreen trees have a high oil and wax content and a greater burn potential. Leafless, deciduous trees that have an open loose branching pattern are more likely to survive. Trees stressed due to drought, injury, disease, insects are weak to begin with and unlikely to survive.

To determine if a tree will survive, look to see if the bark is completely burned off exposing the tender tissue underneath. When the bark is gone, the tree probably won’t survive. If there is bark, cut a quarter-sized piece off to see if there is a green or white layer immediately below the bark. If the layer beneath is green or white, the tree has a good chance of recuperating. If the trunk is severely burned for more than 50 percent around the circumference, the tree will probably die, although some thick-barked trees may survive. To check if burned branches are alive, peel back a bit of bark on twigs. If there is a thin layer underneath that is green or white and it is moist, the twigs may be alive. Wait to see if they have spring growth before pruning these branches. Where the fire burned deeply into the trunk, the tree will be unstable and survival is unlikely. These are hazard trees and should be removed. Evergreen trees may survive if more than 10 percent of their foliage is still green. Whether evergreen or deciduous, check the buds. They should be moist not brittle.

See if the roots are burned around the base of the tree. Gently brush away soil 6 to 8 inches deep in a few locations and see if roots appear supple rather than dry and brittle. If 50 percent of the roots have been burned, the tree is unstable, may be toppled by wind and is likely to die.

To care for fire damaged trees water them as soon as possible. Plants will need water because soils were dried out by the fire. Some soils may repel water. Fire-damaged and water-stressed trees are more susceptible to bark beetle attack. Prune off dead, broken or severely damaged limbs. Trees that must be cut down should be removed from the property to avoid beetle infestations.

After a fire, when evaluating what steps to take, think about safety first. Check for unstable trees or tree limbs that may fall. Then, take care of remaining trees and be patient. Many trees can survive a fire.

For more information on landscape care after fire see the University of Nevada Cooperative Extension publication Taking Care of Residential Trees after Wildfire or contact JoAnne Skelly at 775-887-2252 or skellyj@unce.unr.edu.