Invasive pests can burrow into trees that then become firewood. When the firewood moves, the pests move with it—without the transporter knowing—to uninfested areas. Untreated firewood can also harbor other types of insects and diseases that can greatly harm trees and shrubs.
Invasive, tree-killing beetles tunnel into trees and eat their insides. Leaf-munching caterpillars can strip trees of their leaves, leaving those trees vulnerable to other pests and diseases that could kill them.
Your backyard and neighborhood trees and shrubs, America's forests, and jobs supported by the forestry industry—not to mention your ash baseball bat and breakfast maple syrup. Wildlife that depends on forest ecosystems could also suffer.
Deny these hitchhikers a free ride in your firewood. Buy firewood where you burn it. If you must move firewood (even just a short distance), make sure it has been heat treated to kill any pests that might have been in or on it.