WHITE PINE UNDER FOREST MANAGEMENT. 41 
every 12 years. The strips should run as nearly as possible at right 
angles to the prevailing winds. While, as with two cuttings, a width 
for the strips of 100 to 150 feet is best, the width of the intervening 
strips of standing timber must be sufficient to insure that the 3, 4, 
or 5 cuts will entirely remove the stand. If, for example, the average 
acre yield at 60 years of a 16-acre tract of pure white pine is 30,000 
board feet, and the installation of a portable mill is warranted by a 
cut of 100,000 board feet, or 3^- acres, 5 such cuttings at 12-year 
intervals would be possible with a rotation of 60 years. The side of 
the stand most nearly parallel to the prevailing wind should be 
divided into 5 parts, and each of these into approximately equal 
subdivisions from 50 to 100 feet wide. Each of the cuttings will 
then follow every fifth strip at right angles to the prevailing wind. 
Very few stands, however, are uniform throughout, and the width of 
the strips will have to depend somewhat upon local variation in the 
yield. 
Any system of sustained yield through regular cuttings presup- 
poses the existence of a reasonably steady market for the grades of 
lumber supplied. White pine lumber of medium and low grades 
promises to remain as steadily in demand as that of any other species 
in the Northeast. Even white pine lumber, however, will fluctuate 
in value, and the temptation will often be strong to overcut when 
the market is high, and lightly or not at all when the demand is poor. 
While modification in the original plan can be made only at a sacrifice 
in regularity in ensuing yields, it can not always be avoided, and 
constitutes a defect in the strip system. Absolute regularity, how- 
ever, is often undesirable, even from a silvicultural standpoint, since 
a year's delay or hastening of the cut to take advantage of a seed year 
may greatly facilitate reproduction. 
One great advantage of the strip method over clear-cutting the 
whole stand is the greater certainty of reproduction it offers. Should 
the young reproduction be destroyed by fire, the standing timber to 
windward can be depended upon to reseed the area. In fact, a light 
fire just before a heavy fall of seed, provided it is not allowed to 
spread into adjacent timber, may prove of great value by exposing 
the mineral soil and killing existing vegetation. As when only two 
cuttings are made, the last strips to windward may be reproduced by 
leaving seed trees or by planting or sowing. Disengagement cuttings 
will often be necessary to remove competition from fast-growing 
hardwood sprouts and underbrush. 
Clear cutting with scattered seed trees. — In this method natural repro- 
duction is secured by leaving three or four mature seed-bearing trees 
to the acre (see PL IV, fig. 2). These should be distributed as evenly 
as possible, but located with reference to the prevailing winds in a 
way to insure the most effective distribution of seed. Seed trees 
