In computing products, the trees were estimated in posts, poles, 

 logs, or cordwood, according to species and size. The estimate of 

 yield in posts, poles, and logs was based upon actual count; that in 

 cordwood upon volumes of sample trees or upon volume-diameter 

 curves constructed for the purpose. a All posts and stakes are 

 assumed to be 7 feet in length. Sticks from 2 inches to 2.9 inches in 

 diameter at the top are classed as stakes, from 3 inches to 3. 9. inches 

 as second-class posts, from 4 inches to 5.9 inches as first-class posts, 

 from 6 inches to 8.9 inches as two first-class posts each, and from 9 

 inches to 11.9 inches as four first-class posts each. All poles have a 

 top diameter of 5 inches. Logs have a top diameter of 10 inches or. 

 more and are scaled by the Doyle rule. A cord of wood is assumed 

 to contain from 73 to 88 solid cubic feet, according to the size of 

 material. 



The prices assigned to the various products were determined by 

 comparison with the prevailing prices of similar material of other 

 species, together with estimates of quality and durability. The 

 prices are purposely made low in order that the conclusions drawn 

 from the study might be conservative. The price of native white 

 or bur oak posts in Illinois ranges from 8 to 15 cents. The cost of 

 cutting such posts is usually from 2 to 2^ cents each. The market 

 price of the native woods ranges from S3 to $6 per cord, according to 

 location and quality. The cost of cutting is about $1 per cord. 



DETERMINING THE VALUE. 



In the tables the stand, yield, and value of the products are 

 reduced to the basis of 1 acre throughout. Stumpage prices are 

 assigned to the various classes of products. The cost of establish- 

 ing each plantation is figured at 3 per cent compound interest for as 

 many years as the plantation is old, and this amount is deducted 

 from the gross value of the plantation to determine its present net 

 value. The figure under the heading " Annual income at 3 per cent" 

 is the sum which, if placed at 3 per cent compound interest during 

 each successive year from the date of planting, would at present 

 amount to the net value of the plantation. The value of the plan- 

 tation is computed in this way in order that the profit from forest 

 planting may easily be compared with that from farm crops. 



In consequence of this method, also, the price of land and taxes 

 do not enter into the calculations. For example, if a certain piece 

 of land has on it a catalpa plantation which at the end of twenty 

 years shows an annual income of $8 per acre at 3 per cent compound 

 interest, when the annual income from ordinary farm crops on the 



These curves show how the volume of a tree is related to its diameter, so that for 

 trees of all diameters the corresponding volumes are known. 

 [Cir. 81] 



