DETERMINATION OF THE MIDDLE DIAMETER OF A 

 STANDING TREE^ 



By p. d'AbovilIvK 



The diameter at the middle of the trunk of a standing tree, which 

 is necessary in order to determine its contents, cannot be measured 

 directly. It is necessary, therefore, to have recourse to a coefficient of 

 form which, multiplied by the diameter at the butt, will give the 

 diameter sought. 



If /■" represents the coefficient of form, (/ the diameter of the butt at 

 the height of one's eyes, and d' the diameter at the middle of the trunk, 

 then 



d' = dy: f. 



This coefficient of form is variable. It changes not only from one 

 forest to another, according to the site and to the nature and age of the 

 stand, but also from one species to another, and often for each tree of 



" Translated by Samuel T. Dana. U. S. Forest Service, from an article entitled 

 "Determination du diametre au milieu du tronc de I'arbre sur pied," in the Revue 

 des Eaux et Forets for June, 1919. 

 802 



