of Growing Timber Trees. 353 



It will be observed in all these tables, that when trees have 

 doubled their age, there are only one- fourth of the number 

 remaining on an acre, in consequence of their distance being 

 doubled ; but as each tree will then have increased its con- 

 tents eight-fold, therefore the number of feet on an acre 

 must be then doubled. Above, at 64 years of age, there is 

 exactly double the number of feet that there is at 32 years 

 of age. 



And if trees be periodically thinned out to the distance of 

 one- fifth of their height, and that they increase eighteen 

 inches in height, and two inches in circumference, annually, 

 the number of trees on an acre, and the number to be cut 

 out at different periods, and the number of feet they will 

 then respectively contain, will be as under, viz. 



TABLE V. 



But if the trees be first planted four feet apart, and be 

 periodically thinned out to the distance of one-fourth of 

 their height, and that they increase twelve inches in height, 

 and one in circumference, annually, the number of trees oa 

 an acre, and the number to be cut out at the ages and heights 

 under mentioned, and the number of feet they will respec- 



Vol. 33. No. 133. May 1800. Z tively 



