FOREST SURVEYS ON MICHIGAX STATE FORESTS 573 



are used in determining the types ; all that is attempted is that the de- 

 scriptions and maps shall portray the composition of the stands of the 

 forest as truthfully as is possible. 



Each tree in the region is given a color, and the type is colored after 

 that species which predominates in the type in numbers. The general 

 descriptive names which are used when no one species predominates 

 are also given a color. Burned potential forest areas are typed as 

 burned if the burn has occurred within a year or two. They are given 

 a distinctive color. 



The boundaries of the types usually are formed by fires or by quality 

 of site. 



Unless the type is very distinct, it is not mapped unless it covers five 

 acres or more. 



When two men compose the crew, the types are mapped by the esti- 

 mator ; when a three-man crew is used, the computer maps the types. 



PLANTING AREAS 



It is of the utmost importance to the forester in the preparation of 

 a planting plan by which the work will be conducted most efficiently; 

 that the areas in need of planting be indicated on a map. By the use 

 of the site map and forest description, it is hoped that the species of 

 trees best suited to the area may be determined. The number of trees 

 of each species needed each year can then be determined and prepara- 

 tions made in the nursery for raising this number. 



Whether or not an area should be planted depends, primarily, upon 

 the density of the present stand. If it is too dense, planting may not 

 be undertaken for either or both of two reasons, namely, (i) on ac- 

 count of the mechanical hindrance to preparation of the soil for plant- 

 ing the trees, (2) on account of the amount of shade which would 

 certainly inhibit the growth of the seedlings and perhaps kill them. 

 But the density of the shade is not the only determining factor, for 

 whereas an acre with perhaps fifty small oaks on it would be planted, 

 another acre with fifty small Norway pines 20 to 30 feet high would 

 not be planted. The oak is an undcsiral)le species and is to be replaced 

 by planted coniferous stock ; but the Norway pine is a desirable species, 

 and it is expected that it will sooner or later restock the ground with 

 its own seed. 



Again, the quality of the site is a factor to be considered in planting, 

 for whereas, for example, on site I underplanting might be feasible 

 under a specified density of crown, on site III under])lanting would 

 not ])v feasible. 



