FOREST MENSURATION. 181 



for the period of rotation, thus leaving the capital stock 

 unimpaired. The methods of measurement described 

 are used in outlining this plan. 



The Estimation of Standing Timber is usually a matter 

 of personal experience on the part of the estimator. No 

 measurements are taken of trees, but the estimate is made 

 by men of long experience in the woods. Sometimes 

 their figures are very close, but more often they fall short 

 of the actual stand of timber. Buying and selling timber 

 lands is based on this method of determining the possible 

 crop, both parties sending out their own estimators. The 

 number of trees on typical areas, as an acre in each forty, 

 may be counted, and the sizes estimated. Often all 

 timber trees on a forty-acre lot are counted, and the number 

 of logs per 1,000 feet board measure estimated. 



For an inexperienced person a good method would be 

 to caliper all trees on typical areas of the tract and then 

 compute the stand from the cross-sectional area and the 

 average length of timber stick, which could be estimated 

 very closely after a httle practice. The greatest difficulty 

 in this w^ork lies in the selection of tj^ical areas and 

 sample trees. All forestry measurements and estimates 

 are only approximations, and it is often found necessary 

 to modify working plans to meet new information and 

 changed conditions. 



MEASUREMENT OF LOGS AND LUMBER. 



Logs are Measured in Feet Board Measure in Ordinary 

 Practice by taking the length and diameter at the small 

 end, and by reference to a table, the corresponding number 

 of feet, board measure, is found, which it is assumed could 

 be sawed from the log. This is not usually accurate, but 

 seems to be sufficiently so for business purposes. Lumber 

 is measured in square feet of surface of a board one inch 



