Page 24 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

1.24 THE WORK

wheel driven by a tractor or truck power takeoff. Cutting is usually carried 4 to 6 inches below
ground level.

Tree Killing. Under most conditions dead stumps are easier to remove than live ones, because
of the disappearance of the hair roots which bind them to the earth and the weakening of the larger
roots. Softwoods in well-drained soils may show perceptible weakening in a few months, while rot-
resistant stumps in saturated ground may remain firm for many years. In any case, dead stumps
contain lighter wood and hold less dirt than live ones.
It may therefore be advantageous to kill trees well in advance of removal in cases where plans
are made early enough. This may be done by cutting, girdling, poisoning, burning, or drowning.
The same methods are not equally effective in different localities with different species, so advice
should be obtained from local tree experts.
Burning peat soils in the dry season will kill trees and loosen the stumps, but because of smoke
and smell nuisance, and danger of spreading, it should be done only under carefully controlled
conditions.
If it is possible to dam a stream so as to flood a wooded area for several months during the
growing season, some of or all the trees may be killed. Unfortunately this usually is possible only
in swamps, and swamp trees are more resistant to drowning than those in dry locations.

PULLING STUMPS

Stumps may be pulled out of the ground by a cable to a power source. This method, although
widely used, is less popular than in the past. Bigger machinery and special attachments have made
it possible to push or dig out most stumps encountered on construction jobs, without taking the
extra time to rig lines.
However, such equipment is not always available, it may cause too much damage, and it can-
not work efficiently on soft ground. Pulling will probably continue to be an important method of
stump removal.
The pulling line may be a chain, cable, or rope, and the power may be direct pull by a machine
or animal, winding in of cable on a winch, either machine- or hand-powered, or a combination of
these methods with pulley blocks.
The stump line is generally a choker type which tightens its grip as the pull increases. In smaller
sizes, chain is preferred because it is easier to carry, safer to handle, and more resistant to abuse.
However, it is much heavier than cable for the same strength, and in large sizes it is too weighty
to be practical.
Line pulling is preferred when the ground is too rough or soft to allow machinery to get at
stumps directly, and when available force needs to be increased by multiple lines.

Chains. A more detailed description of chain and fittings will be found in Chap. 21. A standard
tow or logging chain is composed of short straight links, carries a round hook on one end and a
grabhook on the other. The round hook may be fastened to the chain by a ring, or a ring may be
used instead of this hook.
Either the round hook or the ring can be used in chokers. The hook is easier to attach and to
detach, but may fall away from the chain when it is slack. The ring may be used by passing the
grabhook through it and pulling from the grabhook end; or for stumping, the chain near the ring
may be pulled through it to form a loop that is dropped over the stump.
The grabhook fits over any individual chain link, and will not slide along the chain. It is used
to adjust the length of chain by increasing or decreasing the amount of double line, by moving it
toward or away from the choker end, or by passing the chain behind a tractor drawbar pin, and
preventing it from being pulled out again by attaching the grabhook to the slack side, making it
too large to be pulled through the space. In this case the surplus chain is slacked, and if it is long,
must be hung on some part of the tractor. See Fig. 1.18.