Page 6 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

1.6 THE WORK

FIGURE 1.1 Brush chipper.

At the opposite end of the scale are monsters which can gulp down entire trees, with trunks up
to 20 inches in diameter, without need to even trim the branches.
The chips that are produced may be a definite asset, may be a problem, or may have no
importance.
A few modern paper mills are able to digest wood chips that include bark and twigs, and will
pay good prices for them. If such a mill is within economical hauling range of a clearing job, chip-
ping pays off both in money and in utilization of the wood. In other areas, chips might be sold for
processing into pressed wood, or charcoal and distillation products.
There is also a possibility that chips can be used on the job, either because they are really useful
or because it is the best way to get rid of them. They can hold soil on slopes while vegetation becomes
established and can add organic material to poor soils. Some applications are discussed in Chap. 7,
together with possible problems.
Chips from light to medium thickness of vegetation may be left scattered on the ground, to be
incorporated with the topsoil when it is pushed off or cultivated. If the growth is heavy, the chips
are likely to make the soil critically short of nitrogen, and difficult to work, and to accumulate in
spots as pockets of almost undiluted wood.
Chipping is usually not practical for uprooted stumps, unless they are very small in proportion to
machine capacity. Their bulk and shape make it difficult or impossible for the guards to pass them or the
drums to grip them, and the dirt and rocks stuck to them damage cutters and make the chips unsalable.
Chips made from stumps in the ground are always contaminated with dirt.
Piling chips, either by keeping a discharge chute in one direction or by dumping them from
trucks off the work area, should be permitted only when they are to be reclaimed later. Such piles
are likely to remain for many years before decaying enough to permit growth of vegetation.
Chipping machines are expensive, consume large amounts of fuel, are extremely noisy, and
may be dangerous to personnel. Their use in mass clearing is justified when there is good use for
the chips, in areas of high fire danger, or where smoke cannot be tolerated.
In addition, chippers are valuable in low-volume or selective clearing and trimming, where the
cutting would otherwise have to be hauled away.
Removal from Area. Removal of cleared vegetation from the work area may be anything from
a sound and profitable operation to a financial and ecological disaster.
Where lumber or paper mills are within economical hauling distance, it may be possible to sell
cut trees profitably. In some cases, the user of the wood may be glad to cut and remove the usable
part of the vegetation and pay for the privilege.