CALIPERING STANDS 213 



border trees or broken trees by diminishing the circumference. 



Average heights are obtained by eye estimates, by measuring sample felled trees, 

 or by some simple method such as the use of two sticks of equal length. 



The chief of detachment or tally-man also determines for each stand the .average 

 middle circumference for each breast-height circumference class. This is usually done 

 by eye or by determining the average taper per meter of length by measuring sample 

 felled trees. In the large fir of the Jura it is impracticable to estimate the middle cir- 

 cumference, and volume is taken from tables based on circumference at Im50 and 

 curved heights. 



For felled trees the length and middle circumference outside bark is taken. 



Maritime, Scotch, and Austrian pine are tallied separately. In hardwoods, where 

 occasional individuals of several species occur, these are tallied with the more numerous 

 species which they most closely resemble, for example, poplars as birch, locust as oak, 

 and hornbeam as beech. Sometimes larch is thus tallied as Scotch pine. 



Small trees which would be broken during felling operations are sometimes marked. 



Standing dead trees are tallied if sound. 



Cordwood. In stands of pine the amount of fire-wood in steres is roughly taken as 

 one-fifth of the number of cubic meters of saw timber, unless the chief of detachment 

 considers the conditions unusual, when he estimates the variation accordingly. In 

 the silver fir forest of Levier, Doubs, the number of steres of fire-wood was taken as 

 one-tenth of the number of cubic meters of saw timber. 



For hardwoods the chief of detachment estimates for each stand according to condi- 

 tions whether the number of steres of fire-wood is 1, If, or 2 steres to the cubic meter of 

 saw timber. 



Estimates of coppice are made in steres per hectare, according to species, age, density, 

 etc., and depend much on the experience of the estimator. 



Reports on private forests consist of the tally (kept much the same as in America), 

 the estimates of fire-wood and other products, and a description of the various factors 

 of location which affect the value of the timber. 



Computation. Using the middle circumference and height to a top circumference 

 of 60 cm., the volume is taken from a table of contents of cylinders. The same method 

 is used for all species, except in the large fir timber of Doubs State Forests where the 

 tally-man records the cubic contents of each tree directly in the field from a volume 

 table. Although volume tables exist for the pines of the Landes, men of the C. F. E. 

 say that no tree tables are used in that office. 



Accuracy. The methods used are probably as nearly accurate as any in common 

 use. For saw timber the principal factor affecting the estimate is height. Pine stands 

 are usually uniform and the average height by circumference classes can be estimated 

 closely. 



In the large fir timber in the selection forests of Doubs and Jura, separate volume 

 tables are used for distinct site classes where the height growth varies greatly. 



For hardwoods the height of each tree is estimated and French foresters vary greatly 

 in their height estimates. One chief of detachment may instruct the men to take heights 

 only to the first large branch, fork, or serious crook, while another may insist that 

 heights be taken to the top circumference limit as long as the trunk can be divided into 

 straight log lengths to eliminate the effect of crook, etc. In hardwoods the height factor 

 greatly affects the accuracy of the estimate. 



Cordwood estimates depend much on the experience of the estimator, and can be 

 only approximate. Wherever possible measurement of the piled wood after cutting 

 should be made. 



For saw timber under American methods of exploitation, check scales of logs after 



