Forestry mulching is a land clearing method that uses a single machine to cut, grind, and clear vegetation.
A forestry mulching machine, also referred to as a forestry mulcher, forest masticator, or brushcutter, uses a rotary drum equipped with steel chipper tools (“teeth”) or blades to shred vegetation. They are manufactured as application-specific tractors and as mulching attachments (“mulching heads”) for existing tracked and rubber-tired forestry tractors, skid steers, or excavators.
Heavy duty forestry mulchers can clear up to fifteen acres of vegetation a day depending on terrain, density, and type of material. Forestry mulchers are often used for land clearing, right-of-way, pipeline/power line, wildfire prevention and management, vegetation management, invasive species control, and wildlife restoration.
Forestry mulching is used in the right-of-way clearing and maintenance for roads, highways, pipelines, and other utility lines. This process often requires complete removal of standing trees, stumps, and vegetation.
Forestry mulchers can be used in commercial and residential land clearing projects such as site preparation and development, cutting and clearing brush, nature and recreational trail creation, and seismic exploration.
Forestry mulching has become popular among nonprofit riparian conservation organizations, government agencies, hunt clubs, and private land owners in attempts to maintain habitats for pheasants, doves, elk, deer and various other animals. Maintaining an animal habitat encompasses several different aspects: food, water, shelter, and space, and there are many products that can help reclaim and maintain wildlife habitats for these animals.
Some common invasive plants such as tamarisk (salt cedar), Pinyon-juniper (pj), Russian olive, Juniperus virginiana, buckthorn, and multiflora rose can invade a natural habitat, soak up a tremendous amount of ground water, and need to be removed to reestablish the native habitat or to preserve the water table. Invasive insects such as pine beetles can also devastate forests, leaving behind rotting trees with diminishing timber value and that may become falling hazards if they lose their ability to stand up against wind.
Proactive mulching can reduce stress on trees caused by crowding, making them less susceptible to attack from invasive species. Mulching invasive species in place can control the spread of invasive plants, insects, and fungus. The mulching action tends to discharge the material downward and within a reasonably confined area, versus other methods such as rotary cutters that may laterally disperse pine beetles or other invasive species into neighboring healthy trees.
By processing trees and other vegetation where they stand, mulching machines eliminate many of the steps involved in land clearing such as site prep, cutting/felling/hauling, and site cleanup. This also eliminates the need for multiple machines such as a bulldozer accompanied by some combination of excavators, tree shears, wood chippers or grinders, and hauling equipment. On simpler jobs only one mulching machine is required, reducing fuel requirements and emissions.
Some mulching machines also have the ability to operate on steep slopes and in small or tight areas, in poor ground conditions, and in wet or snowy weather.
Mulching machines are capable of clearing land of unwanted trees and brush with limited disturbance to soils or desirable vegetation.
Traditional land clearing methods often present an increased risk of erosion by pushing over trees, uprooting the stump and roots, and substantially disturbing soils. In contrast, mulching the vegetation leaves the soil structure intact. The mulched material can be left on the ground and will act as an erosion barrier while returning nutrients back into the soil through decomposition. Over time, grass will naturally grow through the mulch and can be maintained with mowing.
Depending on the size and orientation of the mulching head, forestry mulchers can only fell smaller trees. Mulchers with a mulching head that rotates about a vertical axis can typically handle trees up to 6-8 inches in diameter, while mulchers with a mulching head that rotates about a horizontal axis can handle trees up to 30 inches in diameter. Mulching trees at the upper end of this size range can be dangerous for both the equipment and the operator. Some excavator mulching attachments are equipped with a tilting bracket that significantly reduces the risk of felling trees larger than those desired. Mulching areas with a variety of vegetation and terrain may require multiple pieces of equipment, including tracked mulching machines, excavator mulchers, and skid steer tractors equipped with mulching attachments.
Rocks and stones cannot be processed or moved by the machines, and the teeth grinding against rocky ground can both wear them out and cause a fire hazard. Blades, hammers and teeth are replaceable and considered wear parts. Smaller rocks and other debris can be thrown through the air, and while these are usually deflected by a protective shroud, they can present a danger to the operator and surrounding people and structures.
Even for the largest machines, mulching is only effective when less than 25 tons of vegetation or 100 trees are present per acre.
Although mulching is significantly faster and less labor-intensive than land clearing by hand, it requires the site to have road access for fueling and maintenance.