176 FARM FORESTRY 



high degree of accuracy is not necessary in measuring a stand- 

 ing tree for purposes of estimating the contents. When the 

 entire tree is considered as a paraboloid it means that if the 

 twigs and limbs were all squeezed up together they would 

 rarry up the solid trunk of the tree with a gradual taper to 

 the tip. 



If the solid contents of a cone is found by multiplying 

 the area of the base by one- third the height, then the volume 

 of the tree, which is a little larger than the cone, will be found 

 by multiplying the area of the base in square feet measured 

 at breast height by one-half the total height of the tree. 



Expressed as a formula: 



in which B is the area of the base of the tree in square feet 

 corresponding to the diameter measured at breast height, and 

 H is the total height of the tree. 



The Volume of a Standing Tree in Board Feet. The 

 volume of a standing tree in board feet can be found by 

 dividing the merchantable trunk of the tree into logs by the 

 eye, estimating the top diameters inside the bark of each 

 log and finding the board feet from a log table or by applying 

 the rule of thumb for board feet in logs. The result of the 

 different logs added together will give the estimate in board 

 feet in the tree. 



A rule of thumb well known among timber estimators for 

 finding the volume of the merchantable length of trees in 

 board feet is to subtract 60 from the square of the estimated 

 diameter inside the bark at the middle of the merchantable 

 length of the tree and multiply the remainder by .8. The 

 result will be the number of board feet in the average i6-foot 

 log in the tree. This number is then multiplied by the number 



