THE FORESTER. 



April 



The Way to Estimate Cordwood: A Suggestion. 



Timber estimating has always been an 

 important question both to the lumberman 

 and to the scientific forester. Comparing 

 our own methods in this branch of forest 

 work with those of Europe we find that, 

 while the former are unusually quick 

 and practical, the latter are apt to be much 

 more accurate. We ought to be able to 

 profit from both sources ; to combine what 

 is best in each, or modify it to suit our 

 needs and conditions. 



It is my purpose here to explain a sys- 

 tem of measurement known in Europe as 

 the method by the " absolute factor of 

 shape." Though little used, except in 

 Denmark, it appears to be well suited to 

 many of our hardwood forests for deter- 

 mining their cubic contents or cordwood ; 

 and, with the help of the existing log- 

 rules, to the more uniform softwood for- 

 ests for determining their contents in board 

 feet. 



One or more sample plots within the for- 

 est, representing as nearly as possible the 

 average conditions, are selected and the area 

 of each determined. They may constitute 

 together from one-half per cent, to five per 

 cent, of the total area, according to the 

 uniformity of the forest and the degree of 

 accuracy required. On these sample areas 

 the data are first obtained for calculating 

 their own volume in wood, and from the 

 latter the total volume of the forest or 

 woodland may be readily ascertained by 

 the proportion of the respective areas. 



The preliminary measurements on the 

 sample area or areas are the following : 



1. The diameters at breast height of all 

 the trees on the selected area, except the 

 very smallest let us say those below three 

 inches. 



2. The heights of a sufficient number of 

 average representative trees of each species 

 to determine the general height-growth 

 conditions of the forest. These trees may 

 be selected while taking the diameters and 

 should include small, intermediate, and 

 large trees of each kind, if present. The 

 respective diameters should be noted in 



connection with the heights. By point 

 ing off the heights on cross-section pape 

 in conjunction with the corresponding di 

 ameters and drawing a graduated curv 

 through these points, the relation existin: 

 between heights and diameters for ever 

 size of tree may be quickly found. 



3. The volume of the stem above breast 

 height in several average representativ 

 trees for each species. The method b 

 sections is the best, as it is accurate an 

 easy, and generally familiar. The fu! 

 height of the tree and its diameter a 

 breast-height should be noted in connec 

 tion with the stem volume in each case. 



In deciding what constitutes the stem o 

 the tree, something must be left to th 

 judgment of the estimator. In conifer 

 the solution of this question is general! 

 easy. In them the upper portions of th 

 tops may sometimes have to be discarded 

 while, on the other hand, the stems of hard 

 woods usually do not extend far into th 

 crowns of the trees. The measurement 

 should not extend beyond the needs c 

 the case and should conform to the actu 

 available use of the wood. 



These trees, of course, will have to b 

 felled; but since an estimate of the timbe 

 is usually followed by a cutting or is cor 

 temporaneous with it, this circumstanc 

 should not be objectionable, especially a 

 the trees may often be selected so as to iir 

 prove the si Ivi cultural conditions of th 

 forest. 



The measurements under 3 are take 

 in order to determine the " absolute facto 

 of shape " for each species. Thi 

 " factor " is simply the proportion betwee 

 the volume of the stem obtained as alread 

 explained and the volume of an imaginar 

 cylinder having the same basal area as th 

 stem and extending in length from th 

 same level at breast-height vertically to th 

 tip of the tree. Thus, in a tree whos 

 basal area at the level of breast height i 

 1.2 square feet, whose height from thn 

 same level to the tip of the tree is 65 feet 

 and whose stem volume between, as ascei 



