Blower Clears Established Firelines in Hardwood Forests Without Disturbing Soil
Shawnee National Forest Site Visit
On April 26, 2007, MTDC project leader Keith Windell visited the Shawnee National Forest to better understand the forest's needs and the working environment. Forest Service employees from the Shawnee National Forest who participated included Jon Teutrine (Hidden Springs Ranger District's fire management officer, figure 1) and Tom Neal (forester).
Figure 1—Fire Management Officer Jon Teutrine in
typical Illinois hardwood
forest.
During the visit, Windell intended to gain a better understanding of the forest's equipment needs, examine the mobile machinery the forest already owned, walk on the prescribed firelines the proposed attachment will be used to maintain, and discuss some equipment options MTDC had been thinking about.
The forest's basic need is to remove leaf litter that collects on previously established prescribed firelines (figure 2). Leaves need to be removed from a line at least 3 feet wide and preferably 4 to 5 feet wide.
In many areas, equipment wider than 5 feet would not be able to maneuver through the fireline corridor. Obstacles include small logs and branches (figure 3), waterbars, closely spaced trees, occasional small saplings, sharp turns in the fireline, and steep, narrow gullies. The line is sometimes boggy and machines occasionally get stuck and have to be winched out. Whatever equipment is developed to maintain the firelines should not destroy the existing waterbars.
Figure 2—Tree spacing can be tight in hardwood forests.
Figure 3—Typical debris found beneath leaf litter
on the hardwood forest
floor.
In the past, existing firelines have been cleared with a straight blade mounted on a dozer. John Depuy, the soil scientist on the Shawnee National Forest, notes that clearing the firelines with a blade removes the productive A-horizon soil layer, which is undesirable. Now, hand crews clear existing firelines on foot, using chain saws and portable backpack blowers. One sawyer and three crew members with backpack blowers can clear leaves from about 40 chains of fireline per hour (a chain equals 66 feet). One desirable feature of the blowers is that they do not form berms of leaves on the sides of the fireline.
The Shawnee National Forest staff hoped that MTDC's solution would use equipment that the Shawnee National Forest already owned. Equipment mounted on a trailer was probably not a good solution because the trailer would have to be pulled through steep, narrow gullies. Equipment attached directly to a prime mover could be raised when crossing steep, narrow gullies. Another option would be to mount the equipment in the back of a prime mover.
The Shawnee National Forest owns a John Deere JD450 crawler tractor, a New Holland skid steer with steel tracks over rubber tires, a Sweco trail dozer, a John Deere Gator (UTV), a Polaris Ranger (UTV), numerous ATVs, and an IHI IC-30 crawler carrier.
Shawnee National Forest staff members felt that the New Holland skid steer and Sweco trail dozer are heavily used for other purposes and would not be available for maintaining prescribed firelines. The skid steer might be unstable on sidehills. The Sweco trail dozer has not held up well in some rough areas of the forest. Trail construction implements had to be reattached after the implement's attachment bolts sheared off.
The Polaris Ranger UTV (figure 4), the John Deere XUV Gator UTV, and several ATVs all had light frames that did not seem suitable for mounting an attachment in the front that could be raised easily to clear a steep, narrow gully.
Figure 4—The Polaris Ranger UTV that Shawnee National Forest staff
members wanted to use for clearing prescribed firelines.
Quadivator Inc. (http://www.quadivator.com) makes a front-mounted ATV Power Broom. The Power Broom has a self-contained power unit at the back end of the ATV. A frame mounted under the ATV uses rubber belts to transmit power to the broom. The Power Broom did not seem suitable for the rough terrain on the Shawnee National Forest. The UTVs and some of the ATVs had small utility beds that could accommodate smaller slip-in units.
The JD450 (figure 5) crawler tractor was not considered available for clearing the existing firelines because it might be needed to suppress wildfires. It would be unwise to have to reconfigure the JD450 with initial attack implements after the unit receives a dispatch to a fire. Another drawback is that the JD450 requires a skilled operator, a large transport trailer, and a driver with a commercial driver's license. During some periods, weight limits are reduced and road surfaces become boggy, which could prevent the JD450 from being brought to areas where firelines needed to be maintained.
Figure 5—The JD450 crawler tractor that the Shawnee
National Forest uses
for fire suppression.
The IHI IC-30 (figure 6) crawler carrier was considered for the task because it has a robust machine frame and bed on back. The main drawback to using the IC-30 is that it does not have an auxiliary hydraulic circuit to power implements.
Figure 6—The IHI IC-30 crawler carrier owned by
the Shawnee National
Forest.
The IHI IC-30 has overheated, but this could be a correctable maintenance issue rather than an inherent design flaw. The IC-30's limited hydraulic system does not lend itself to diverting fluid to power a sweeper or blower. It might be possible to pull about 8 or 9 gallons per minute of flow without automatically locking up the IC-30's brakes, but the IC-30 would have to operate in low forward speed range. A slip-in, self-contained power attachment or an attachment that does not require power at all would be needed for the IHI IC-30.
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