THE SHELTERWOOD SYSTEM 157 



except that the seed-cutting is a much heavier thinning. 

 The aim is to cut such defective, malformed, and sup- 

 pressed trees as are left from the preparatory cuttings. 

 The larger trees with spreading crowns are taken, because 

 of their possible danger to the reproduction if left for 

 later cutting. Trees of undesirable species, likely to re- 

 produce themselves in competition with the good species, 

 are also cut. Just as in the preparatory cuttings, the 

 trees to be left are of moderate size, and chosen from the 

 dominant class. They should be thrifty and capable of 

 rapid growth during the remainder of the period of re- 

 production. They should also be capable of producing 

 seed, since they not only must produce the greater part of 

 the seed for the first reproduction, but are also counted 

 on to seed up any gaps that may occur. 



In general character, the thinning is uniform — that is, 

 it extends over the whole stand. Usually, however, it is 

 not necessary to be very precise in spacing the trees at a 

 uniform distance. It may happen that a given site is 

 subject to danger from frost, and that protection of the 

 small trees in the earliest period requires a uniform cover. 

 Even if the trees are not regularly spaced, a uniform 

 distribution of seed may usually be secured. If the seed 

 is distributed by the wind, small openings here and there 

 would be readily covered with seed, as well as the ground 

 under the trees. With trees having heavy seed, a good 

 distribution is obtained if the seed-cutting is made after 

 the ripening of the fruit in a seed-year. There is then a 

 production by all seed-trees left from the preparatory cut- 



