Page 38 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

1.38 THE WORK

FIGURE 1.30 Flame gun.

A standard tool for stump burning is a large kerosene blowtorch, called a flame gun. See Fig.
1.30. It may be blocked to flame against a stump. One person can operate several, or do other jobs
while taking care of one. When the wood starts to burn, the torch may be moved to another stump
and brought back if the fire dies down. Green wood will require continuous heat for many hours.
The torch will operate most effectively if directed into a cavity with an opening in the far end
so that a draft can move through it. If the flame is aimed into a dead-end hollow, very high tem-
peratures will be attained, but because of lack of oxygen the wood will distill rather than burn and
will be destroyed slowly. If the flame is used against the outside of the stump, it should be directed
upward to draw a current of fresh air between the flame and the wood.
Dry stumps may also be burned by starting a wood fire alongside them, and keeping it supplied
with logs and snags placed to almost touch the stump. The draft and reflection of heat will keep
both surfaces burning, but the loose wood must be moved in rather frequently. This method may
remove only the top and outside of the stump, leaving a conical core.
Care should be taken to avoid spreading stump fires. Roots may burn underground to start sur-
face fires at a distance. Soils rich in humus, such as swamp peat or forest loam, may burn unless
saturated with water, and are very difficult to extinguish.

In a Pile. Because of difficulties in burial, and scenic and environmental damage in piling, the
best way to get rid of a pile of stumps is to burn them. However, it is becoming increasingly dif-
ficult to get a permit for the work.
The practical side is also difficult. A stump may cling to more than its own weight of dirt and
rock, most of which should be knocked off to make it burnable. This may be done by allowing the
dirt to dry, then kicking it around with a dozer or other machine, or by picking up with a grapple
and clamshell and dropping.
Even if clean, green stumps are difficult to ignite. If they must be piled before burning, the
base of the pile should include a substantial quantity of old tires, preferably topped by a layer of
logs.
But the surest way is to burn them at the same time they are piled. Build a hot fire by the methods
described in the next section, supply it with enough heavy wood to keep it hot for several hours;
then roll, push, or lower stumps onto it, in sufficient quantity to make a thick mass that can sus-
tain fire by itself.