Reduction of Hazard Fuels

Burnable plant materials in or adjacent to developed areas that could foster the ignition, spread, or increase in intensity of a fire are considered hazard fuels insofar as such a fire could threaten the safety of people, buildings, power lines, or other infrastructure. Hazard fuels may be reduced in order to create a defensible space around developed areas that increases the likelihood that natural ignitions can be allowed to burn outside developed areas, lessens the need for suppression activities, and enhances firefighter safety in protecting structures. Park staff use mechanical or manual thinning of trees and understory vegetation and/or prescribed fire to reduce hazard fuels. Hazardous fuels reduction seeks to balance the goals of protecting valued structures and preserving cultural resources, natural resources, and the aesthetics of the landscape. It is an effort that involves as much art as science. Better aesthetic results are achieved by conducting partial treatments every few years rather than by trying to meet all criteria in one treatment. The extent of vegetation removal is based on the proximity to the nearest structure.

These are typical objectives:

• 0–30 feet: remove all ground and ladder fuels (seedlings, saplings, downfall, standing dead, and trees).
• 30–120 feet: remove all standing dead and 70–80% of ground and ladder fuels.
• 30–400 feet: thin mature trees to achieve an average 20- foot crown spacing.
• 120–400 feet: remove 50% of ground and ladder fuels.

Removed wood may be used for firewood, trail stabilization, or buck and rail fence. When removed plant materials cannot be efficiently or economically used, they are disposed of in the park by burning, scattering, or chipping. Most hazard fuel reduction in Yellowstone is currently done using mechanical and manual methods. However, the National Park Service has proposed to reduce heavy fuel loads in the boundary area of the Northeast Entrance by treating about 900 acres in two phases within the next 10 years, provided sufficient funding is secured and compliance requirements are met.