41 



mining the time that it takes to produce trees of cutting 

 size and in estimating the timber. 



168. The age at which the trees reach the cutting size 

 can be gotten by counting the rings on the stumps of several 

 of the most important kinds that compose the stand. For 

 the tract used as an illustration above where the stand is 

 mostly loblolly pine, 60 years is long enough to allow for a 

 rotation. In the case of longleaf pine, it would hardly be 

 safe to allow less than 100. But it is best to consider each 

 tract separately, with reference to local conditions of market 

 and growth. 



169. The stand in board feet may be obtained by esti- 

 mating the timber on several acres, striking an average, and 

 multiplying by the number of acres. The sample acres 

 should be carefully chosen to insure that they represent the 

 stand. The chances for mistakes are lessened if the sample 

 acres are in the shape of strips. A compass line may be fol- 

 lowed and the trees estimated for 33 feet on each side of the 

 line. This gives a slice 66 feet wide through the timber; 

 and when such a strip is 660 feet long, it represents an acre. 

 A pocket compass, a surveyor's chain, a note book, and a log 

 rule are needed for the work. The direction of the line is 

 found by the compass, then the chain is brought along this 

 line; the trees are estimated on each side of the chain. If 

 there is doubt as to whether to include a tree standing near 

 the edge of the strip, the distance, 33 feet, may be paced, 

 Practice soon does away with the necessity of pacing unless 

 the timber is very thick. When the trees have been estima- 

 ted on both sides of the chain, the direction is found again, 

 the chain is brought forward, and the process is repeated. 

 When the edge of the tract is reached an offset is made and 



