48 BULLETIN -544, U. S. DEPARTMENT OF AGRICULTURE. 
is important particularly in the swamp type and on the more exposed 
slope situations where there is great danger from windfall. In such 
situations the cuttings should be very light, so that the main crown 
cover will continue relatively undisturbed, or everything merchant- 
able on a given area should be cut. This will virtually amount to 
clean cutting, for the nonmerchantable material left will almost inev- 
itably be blown down. 
If the individual cutting area is small, of only one or two acres 
in extent, and flanked by spruce growth either on its windward side 
or above it, reseeding from trees standing on the adjacent area will 
take place following clean cutting. Thus on a level, low-lying area 
groups or patches of timber may be selected for removal and the sur- 
rounding uncut areas depended upon to furnish the necessary seed 
for reproduction. In such a case subsequent cuttings would extend 
these areas gradually until the whole was cut over. 
The exact shape and size of the area to be clean cut, as well as the 
selection of the initial points of attack in starting a groupwise cut- 
ting, depend on circumstances and the object it is desired to attain. 
Areas of advanced young growth may occur under the old woods, 
which it is desirable to free from shading and allow to develop ; advan- 
tage may be taken of groups of overmature or insect -infested trees 
which are stagnating or declining in growth and value and which 
require cutting to prevent loss; or it might be desired to replace 
groups of mixed spruce and hardwoods by pure spruce, or to make an 
opening to encourage pine, ash, or other more valuable species. 
The chief objection to this method in practice is that to insure 
effective reproduction the cleared areas should not exceed from 100 
to 150 feet across. These should be separated by a sufficient amount 
of uncut timber to protect the cleared area from too severe exposure 
to sun and wind and insure the remaining stand against being blown 
down. For economical lumbering, however, a larger area would 
often be desirable. 
CLEAN CUTTING IN STRIPS. 
A better method for extensive cuttings in areas susceptible to 
winclthrow is to distribute the clean cutting in strips in such a man- 
ner that the long way of the strip is at right angles, or nearly so, to 
the direction of the prevailing storm winds. Reproduction of the 
cleared areas would be secured by seeds disseminated from the trees 
in the intervening mi cut timber belts which should be left intact at 
the time of the first cutting, or only very lightly thinned by removing 
small, or overtopped and dying trees without disturbing the main 
crown cover. Whether it is advisable to thin or not depends upon 
the degree of liability to windthrow, and upon the depth of the strips 
in the direction of the prevailing high winds. Instead of the sides 
of the strips in the cutting area being straight, they may be undu- 
