18 A PRIMER OF FORESTRY. 



Thus, by combining the method by volume and the 

 method by area the annual yield of a forest might be 

 established at 250 board feet per acre. This yield 

 might be cut from the forest every year, or it might 

 be allowed to accumulate for twenty years, and then 

 5,000 board feet per acre might be cut. 



SILVICULTURAL SYSTEMS. 



After the yield has been found it must be cut not 

 only without injury to the future value of the forest, 

 but in such a way as to increase its safet\ T and useful- 

 ness. To this end certain ways of handling forests, 

 called silvicultural systems, have grown up. They are 

 based on the nature of the forest itself, and are chiefly 

 imitations of what men have seen happen in the forest 

 without their help. 



From the point of view of forest management, one 

 of the principal differences between trees is whether 

 they spring directly from seed or are produced as 

 sprouts from stamps or roots already in the ground. 

 A forest composed of seedling trees is called a Seed 

 Forest, or more commonly but less suitably, a Seedling 

 or High Forest. One composed of sprouts is spoken 

 of as a Sprout or Coppice Forest, or, more often, sim- 

 ply as Coppice, or as Sprout land. Seed Forests are 

 usually composed of coniferous trees, which rarely 

 sprout, or of broadleaf trees allowed to reach large 

 size. Sprout Forests are common wherever broadleaf 

 trees are cut while they are still young, for the sprout- 

 ing power usually diminishes with age. Sprouts never 

 reach so great a height and diameter as seedling trees, 

 although in youth they grow much faster; and they are 



