574 JOURNAI. OF FORESTRY 



It is apparent that it is not easy to give definite and complete instruc- 

 tions to mappers as to what shall be classified as suitable for planting. 

 But most of the areas which are suitable for planting are readily recog- 

 nized and easily mapped, and these are the areas which are most in 

 need of being planted, being the least heavily stocked. Other areas 

 suitable for planting are recognized only after inspection of the type 

 and site maps, forest descriptions, and timber estimates. The mappers 

 are conservative and are careful not to include areas whose suitability 

 for planting is dubious. 



TIMBER ESTIMATES 



Trees are tallied by d. b. h. and height. Diameters are recorded by 

 two-inch classes, and trees one inch and over d. b. h. are included. 

 Heights are obtained by ten-foot classes, beginning at five feet. Prac- 

 tically all trees are measured ocularly, since by far the larger number 

 of them are under 12 inches d. b. h. and 60 feet high. A roughly made, 

 simple hypsometer is occasionally used to obtain tree heights as a check 

 upon the ocular measurements. Due to changes in density of stand, 

 size of crowns, height of trees, etc., the actual height of the trees is 

 surprisingly deceiving. 



The measurements are kept separate for each type within the forty. 



The figures on the field estimate sheets are copied and summed on 

 the ofiice sheets by the computer. This office work is done nearly as 

 rapidly as the field work, and at the end of the season the estimates 

 are practically all worked up. The operation is very simple. 



The office sheet is 12 inches square and represents four forties. On 

 each forty are recorded the measurements taken on each type. Under 

 each type, then, are recorded the measurements of the trees by species 

 and d. b. h., with the average height for each diameter and the basal 

 area in square feet for each diameter. The actual tally of trees is 

 copied. From this is computed the total number of trees for each spe- 

 cies on the type and on the average acre of the type. The proportion 

 between the number of acres actually tallied and the total number of 

 acres on the type is noted. Figures are not summed by forties, unless 

 the type occupies the entire forty, but only by types (lots) within the 

 forty. 



The trees, as a rule, are so small that they can hardly be considered 

 merchantable and their contents are not computed at this time. Spaces 

 are left on the form, however, so that if ever desired the number of 

 poles, cubic feet, or board feet can be recorded for each diameter and 

 totaled for each species. 



