The Caughlin Fire has raised many questions from homeowners on saving 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:
- Leaf or needle scorch
- Root damage
- Trunk or branch damage
- Inner tissue injury or
- Bud death
Since the Caughlin fire occurred when trees are entering dormancy, trees and shrubs may be more likely to survive. It will depend on fire intensity and length of exposure. 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. Deciduous trees that have an open loose branching pattern are more likely to survive. Trees stressed due to drought, injury, disease or 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. 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 bark survived and the layer beneath is green or white, the tree has a good chance of recuperating. If the trunk is severely burned 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 exhibit growth in spring 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. Check the buds. They should be moist not brittle.
Check to 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 to check 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 will likely die.
To care for fire-damaged trees, water them as soon as possible. Plants will need water because soils dry out or repel water[k1] . Fire-damaged and water-stressed trees and shrubs 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[k2] 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 “Taking Care of Residential Trees after Wildfire” at University of Nevada Cooperative Extension’s website: http://www.unce.unr.edu/publications/files/nr/2004/FS0457.pdf.