342 FOREST INDICATORS. 



accidents. In the latter group will belong temporary types — sprout forests, 

 abnormally open forests, the absence of undergrowth on account of grazing, 

 etc. The classification into types is fundamental and is of importance not 

 only for the present but also for the remote future. Classification on the 

 basis of secondary characteristics, which are merely stages in the evolution of 

 the type, is important only for the immediate future. 



"A comprehensive classification of forests into types should begin by 

 establishing, first, silvicultural units of various orders. The country as a 

 whole should be divided into botanical-geographical regions — as, for instance, 

 northern conifers, central hardwoods, etc.; each region must be subdivided 

 further into subregions — thus the northern conifers into spruce subregion, 

 pine subregion, etc. Within each subregion the forest should be divided on 

 the basis of marked differences in topography and geology into types of forest 

 massives. Each forest massive should then be divided into forest types, and 

 within the boundaries of each type the stands may be further grouped by age, 

 by origin, or by any other distinction which may be due to the interference of 

 man or accident. 



"Without denying the importance of the secondary characteristics in 

 describing and differentiating forest stands, these characteristics must be 

 placed, it seems to me, in a different perspective — at the end and not at the 

 beginning of the work. All attempts at forest classification so far made have 

 been based either upon artificial characteristics or upon characters in which 

 the interference of man was not separated from the natural factors. Such a 

 classification inevitably included in one group stands extremely heterogeneous 

 silviculturally. In order to secure a natural classification and at the same time 

 a complete knowledge of the silvical requirements of the stand, it should em- 

 body in the classification both the natural characteristics and the character- 

 istics produced by the interference of man, but subordinate the latter to the 

 former — that is, the characteristics produced by man should be used for 

 classification only within uniform conditions of growth — the physical con- 

 ditions for growth for the same type must be so similar as to guarantee a 

 biological uniformity of stands." 



Comparison of views. — A careful scrutiny of the opinions just summarized 

 makes it evident that they differ more in emphasis than in fact. While the 

 majority prefer to make use of the community, either actual or potential, 

 they do this as an index to conditions and management. Those who regard 

 the physical factors as the most important recognize the necessity of knowing 

 the composition. The fact that the physical type is defined as one in which 

 the climatic and soil factors are uniform shows that even this view takes 

 proper account of the community, since there is at present no other measure 

 of the uniformity of the factors concerned. In fact, practically every author 

 regards both habitat and community as essential to the adequate under- 

 standing of forest types, and this agreement extends also to the desirability 

 of recognizing and using various kinds of types. This is especially true with 

 respect to permanent and temporary types, and largely also for management 

 types, all of which may be cover types, when the community is emphasized. 

 They are likewise physical types when the chief emphasis is placed upon the 

 habitat or site, but technically, temporary types would usually be excluded. 

 It thus becomes clear that forest types must take full account of both habitat 

 and community, and that the community is the visible sign of any type. It 

 is the indicator of the physical factors of the site as well as of the kind of 

 management which such a community demands to produce the maximum 



