Page 11 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

LAND CLEARING AND CONTROLS 1.11

FIGURE 1.3 Clearing thick brush.

one side, without getting branches in her or his face, and to observe the nature of the ground. In
addition, it avoids tangling the dozer in branches and vines.
Any dozer used for clearing work should be thoroughly protected with crankcase and radiator
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guards; the latter include screen with holes not over ⁄ 4 inch, and accessible for removal of leaves
and trash. The engine needs side guards. The operator should carry hand tools to cut herself or
himself out of tangles.
Minimum operator protection is a strong overhead structure. See Fig. 1.2. Most new clearing
units have complete, extra-strong cabs, often heated and air conditioned.
Accidents have been caused by branches moving throttle and clutch controls.
Other Machines. There are a number of types of equipment that are used for chopping or
shredding brush, which may bury it or leave it on the surface to rot or to be removed by other
equipment or laborers. Refer to Chap. 21 for the special equipment.
A big rotary mower mounted on the rear of a wheel tractor is highly effective up to its thick-
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ness-of-stem limit, which may be 1 ⁄ 2 to 3 inches. Vertical rotary shredders may handle double that
size. Brush is mostly chopped or shattered into small pieces, but root systems are seldom disturbed.
There is no suppression of regrowth.
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The sickle bar or hay cutter, in heavy-duty models, will cut brush up to ⁄ 4 -inch, but with con-
siderable wear and breakage. It does not chop the stems and is little used in clearing.
Either a rotary or a sickle bar can be used to suppress regrowth by repeated mowings.
A big moldboard plow, preferably a brush-breaker model, can put brush and saplings under-
ground, cover them neatly with dirt, and leave them to rot. The area is usually harrowed lightly
and planted to grass or a cover crop immediately.
A big heavy disc harrow, with discs 24 inches in diameter or larger, chops brush and buries a large
part of it. See Fig. 1.4. Big pieces may be loosened, chewed, and pushed around without burying.