340 FOREST INDICATORS. 



on the ground as an indicator of the physical conditions present, and upon this 

 basis ascertains the adaptabiUty of the site for different crops. The obvious 

 objection to the first method is the need of climatological data and soil analy- 

 ses on each site to be classified ; and, owing to the diversity of sites in our forest 

 regions, together with the almost entire absence of climatological records in 

 many sections, the collection of data would involve an expense which, at this 

 stage of our advancement in forestiy, would be almost prohibitive. The 

 second method requires a thorough preliminary investigation in each region 

 to be covered, in order to secure a working knowledge for the actual land classi- 

 fication, and obviously reliable results can only be obtained by the employment 

 of trained men. This method is the simpler and probably the more reliable 

 of the two, and it is considered entirely applicable to the needs of the forester." 



Rockwell (1913: 85) defines four types, as follows: 



"The temporary type is a transitional condition, in which a forest of a 

 temporary character is established as a result of some disaster which over- 

 whelmed the original stand, but which will, if the disaster is not repeated, in 

 time revert to the original climax form. The climax type is named for the 

 species which will eventually predominate as a result of the physical factors 

 concerned, provided the stand is left indefinitely undisturbed. The cover 

 type may be either temporary or permanent; in mature and over-mature 

 stands the name is based on the present composition; in immature stands it 

 is based ujx)n the probable composition at jnaturity. A fundamental type 

 which, similarly to the chmax type, is based on physical factors of site, but 

 named for the commonly occurring species most important from a manage- 

 ment standpoint, instead of for the climax species, will here be called, for want 

 of a better name, the 'physical type.' In addition to furnishing a better basis 

 for the estimate of future yield and the regulation of the annual cut, the 

 knowledge of site conditions which a 'physical' type map supplies is of great 

 assistance in handling all the problems of forest management. After the 

 types have been thoroughly studied, we will know definitely the range of 

 climatic conditions in each type knowledge of great value in forestation, 

 fire protection, and land classification work. We will know what species can 

 grow in each type, their rate of growth, and what they will yield. We will 

 know about the behavior of different species within the type, and can then 

 plan intelligently the management of cutting operations, methods of brush 

 disposal, and other problems of forest management. Not until the physical 

 types are properly classified and mapped can these problems be definitely 

 worked out. " 



Mason (1913:91) recognizes 



"Two classes of forest types. One of these types is based upon physical 

 factors and will be called the 'physical type' ; the other, based on the forest 

 cover found on the area in question, will be called the 'cover type.' A physi- 

 cal-type map is principally valuable in forest management to indicate the 

 species which can be grown most profitably on a given area. It is useful in 

 case planting is to be done, or if a method of cutting merchantable timber is 

 to be selected which will reproduce the proper species. A physical-type map, 

 then, shows the potentialities of the area mapped. It need show nothing 

 with relation to the present forest cover, or even the presence or absence of 

 forest growth. The cover-type map, on the other hand, shows whether or 

 not the area is timbered at all. It shows what kind of timber is now present 

 on the area and its age. It indicates the nature of the crop which will be 



