Biomass Burning Alternatives - Mastication
This page last reviewed July 7, 2008
Mastication involves the use of mobile brush cutters, crushers, and choppers to masticate brush and sub-merchantable material from standing ladder fuels to ground fuels. This operation puts the vegetation (both green and dead) on the ground, where it will have less chance of contributing to a crown fire. After treatment, the material is not removed as a product, but remains in the woods.
Stand Conditions, Equipment and Estimated Costs for Mastication Operations
- Hot Saw Feller Bunchers: ($140
to $190 per hour)
- This equipment can be used in overstocked conifer stands where the objective is to thin smaller trees in preparation for a controlled burn. The hot saw will cut mostly sub-merchantable ladder fuels (less than 8" diameter at breast height) and move the cut material away from the base of the trees. The material can then be run over by the hot saw and compacted to allow for a more efficient burn. However, care must be taken to monitor the amount of slash put on the ground. Too much slash could cause the controlled burn to be too hot, which could kill the remaining trees. The benefit of this treatment is to compact and dry the fuels, which will promote a more efficient burn, while reducing smoldering.
- Crushers and Choppers: ($150
to $225 per hour)
- This equipment is used in areas with slash, brush, and small trees (less than 6" diameter at breast height). This equipment is generally used after a thinning operation, and usually on flat terrain. Choppers and crushers work best with dead material or during winter months when the material is frozen. Machine crushing or chopping is an effective treatment for reducing fire danger, while returning many nutrients back to the soil. This is also an effective pretreatment for controlled burning, because it reduces and evenly distributes the fuels.
- Timbcos and Excavators with Masticating Heads
($130 to $200 per hour)
- This equipment is used in areas with heavy brush and slash. It can also be used to thin trees less than 8" in diameter. Although there are several types of masticating heads, the slashbuster head is one of the most effective tools used for forest fuels treatment. The slashbusting head is typically mounted on a tracked timbco or excavator and can work effectively on slopes up to 45%. The slashbusting head is a circular saw with dull teeth that, due to high rpm's, breaks brush and small trees into chunks less than two feet in length. This equipment is very effective in masticating live green material. This equipment is the most efficient tool for use in brushy fields and on steeper slopes. It is also a very effective tool for thinning trees and brush on plantations. This equipment is an excellent tool for maintenance of fuelbreaks and is frequently used to thin natural stands as a pretreatment before controlled burning.
Advantages of Mastication:
- Effective pretreatment for controlled burning
- Minimal ground disturbance
- Reduces germination of brush species
Disadvantages of Mastication:
- Costly treatment
- May need follow-up herbicide treatment