22 



NORTHERN HARDWOOD TYPE 



yellow and paper birch, beech and maple for manufacture into 

 spools, bobbins or dowels. Naturally this latter class can utilize 

 smaller sizes. The minimum estimating diameters fpr the dif- 

 ferent species found in this type are as follows: 



MINIMUM DIAMETERS 

 Lumber 



Species 



Hemlock 



White pine 



Spruce 



Balsam ._. . 



Paper birch 



Yellow birch 



Black birch 



Beech 



Chestnut 



Red oak 



White oak 



Hard maple 



Red maple 



Silver maple 



Basswood 



White ash 



Cordwood — all species 



Obviously then the first step in planning the estimate of a tract 

 is to find out to what uses the various species can best be put. 

 This is in the main determined by the local industries. Hardwood 

 logs are so heavy that they cannot be hauled long distances. As 

 a consequence it often happens that a tract may have maple 

 admirably suited for flooring but the absence of a planing mill 

 makes it impossible to consider any other use than fuelwood. 



Volume tables exist for all the important species in this type — 

 see Graves' "Mensuration" and Hawley and Hawes' ''Manual of 

 Forestry." While it may be permissible to use a table based on 

 total height for softwoods, merchantable length is the only safe 

 factor for hardwoods. There are two reasons for this. In the 

 first place there is great variation in the usable lengths of hard- 

 woods on account of the size of the branches. The straight main 

 trunk and small side branches of a conifer are entirely different. 

 With the latter it is entirely possible to get a reasonably close 



