280 GEOLOGICAL SURVEY OF NEW JERSEY. 



have reached maturity regeneration is effected by a series of 

 uniform successive thinnings. The number of thinnings depends 

 upon the circumstances of the case. Success in the method 

 depends primarily upon two conditions : First, the trees must be 

 in condition to produce a good crop of seeds ; and, second, the 

 forest floor must be a favorable bed for germination. From that 

 time on the forest must be gradually thinned and finally removed 

 as rapidly as the condition of the young growth will permit, 

 which varies with the species, climate, soil, etc. 



This system is only applicable to pure, even-aged forests. 

 This is a disadvantage, however, because for several reasons the 

 tendency at present is decidedly in favor of mixed growths, 

 Pure growths, especially of conifers, are much more seriously 

 injured by the destructive forces of nature, such as winds and 

 insects, than mixed forests. An excellent form of forest from a 

 silvicultural standpoint consists of a growth of conifers with an 

 underwood of some kind of shade-enduring deciduous trees- 

 The overwood is healthier and the soil is protected and 

 enriched by the underwood. To produce this kind of wood it 

 is necessary usually to resort to the clean-cutting system with 

 regeneration by planting or sowing. 



The fourth system, coppice, is so simple that little explanation 

 is necessary. The crop is simply cut clean year after year, and 

 the new crop is formed either from stump-shoots or root-suckers. 

 Care should always be exercised in cutting the stump close to 

 the ground, with a clean sloping top, so that there will not be 

 the slightest opportunity for rot and so that the young shoots 

 will be healthy and sound. 



In the choice of species for planting and for favoring in mixed 

 growth we should not fail always to consider the silvicultural 

 qualities as well as usefulness for lumber. Fashion often guides 

 us in our choice of kinds, and we should not fail to bear in mind 

 that modern devices of treating wood may completely change 

 its appearance and durability. 



The species of trees which may be successfully grown in 

 southern New Jersey I have divided into two groups first r 

 those which require good soils, and, second, those which will 

 thrive on the poor sandy soils and swamp-lands of the Coastal 

 Plain ; and since the latter are the lands to which the forest will 



