Black walnut, one of the most valuable hardwood timber species in the United States, is being killed by "thousand cankers disease" which is caused by a tiny bark beetle (the walnut twig beetle) and an associated fungus. The disease organisms can spread to new areas through the movement of infested walnut logs, firewood, or other unprocessed wood products that are transported for commercial trade. Heat is a common treatment applied to wood products to kill pests in the wood or bark and make them safe for transport. By steam-heating infested walnut logs to various temperatures in a kiln, and then sampling/monitoring those logs after treatment, Forest Service scientsits and their research partners determined that a temperature of at least 56°C in the outer sapwood for 40 minutes is sufficient to kill all live walnut twig beetles and their associated fungus. This heat treatment schedule represents an effective management tool that can be used to reduce the risk of spreading thousand cankers disease through the walnut wood products industry.