CHOICE OF SPECIES IN ARTIFICIAL REGENERATION 43 



cases where the history of a stand is known, it is a relatively 

 easy matter to determine the quality of the site. Unfortunately 

 in this country the history of stands is usually imperfectly known, 

 and it is often difficult to determine the extent of injury that 

 they have suffered from fire and other external agencies. 



It is often necessary to assess the quality of the site for a par- 

 'ticular species without a stand of trees for guidance. This is the 

 case in seeding and planting on abandoned farm lands, exten- 

 sive areas long denuded of timber, and in prairie regions. The 

 stands of timber on adjacent woodlands are a safe guide in judg- 

 ing the quality of the site of small denuded areas, provided the 

 soil conditions are approximately the same. On extensive areas 

 without timber, such as large burns, the types of vegetation that 

 are present must be relied upon. The particular character of 

 the herbage or shrubs present is indicative of both atmospheric 

 and soil conditions. Thus, certain species of Atriplex are indic- 

 ative of alkaline soils. Ericaceous shrubs indicate acid soils, and 

 cacti and other succulents indicate an arid soil. Thus the lesser 

 forms of vegetation enable us to interpret the site factors and 

 judge the particular species of trees that are most likely to 

 succeed. 



In the indirect assessment of the site factors, the quality of 

 the site or yield capacity is ascertained for the species upon 

 which the assessment is based. When we try to relate this to 

 another species, it should be remembered that the climatic and 

 soil conditions which result in a maximum yield for one species 

 may not result in a maximum yield for another. In seeding and 

 planting operations, therefore, when we desire to use a different 

 species from the one upon which our assessment is based we must 

 know how closely its silvical requirements correspond to those of the 

 species used as a basis for the assessment. 



4. THE CHOICE OF SPECIES IN REFERENCE TO THEIR SUITA- 

 BILITY FOR THE PARTICULAR OBJECT IN VIEW 



Although the first requisite in the choice of species is that those 

 selected are sufficiently correlated with the site factors to grow 

 and develop into an acceptable stand, they must also be suited to the 

 particular object that the owner has in view when the selection is made. 

 The various objects that may be entertained in establishing a 



