of Growing Timler Trees. 35 1 



4th. Consequently, that when a tree has doubled its age, 

 the proportion that its annual increase bears to the contents 

 of the whole tree is then diminished one-half. 



This last observation explains ho^ it comes to pass that 

 a tree, when its age is doubled, the rate per cent, per annum 

 that its increase then bears to the content of the whole tree, 

 is diminished one-half. 



It may not be unuseful to observe, that the rate percent. 

 of increase in the last columns, is the same as the rate per 

 cent, that the increase of the tree that year will pay for the 

 money it. was worth the preceding year. <* 



In the two preceding tables, we find that the rate of in- 

 crease per cent, per annum is the same in both at the same 

 ages, although the quantity of timber in the second table is 

 six times as much as in the first table in trees of all ages j 

 therefore, when the age of a tree is known, tl*e rale;per 

 cent, per annum of its increase is known on inspecting these 

 tallies,^ whether the tree lias grown fast or slow ; provided 

 the growth of the tree has been regular, and that it has con-% 

 tinned its usual growth. 



And having the age, girt, and height, of any tree given, 

 we can readily calculate what quantity of timber it will eon- 

 tain at any future period whilst it continues its usual rate of 

 growth. *»f ^ to *-r 



A Table showing the Number of Trees to be cut out in 

 thinning of Woods, and the Number left standing at every 

 Year., from 20 up to 6*1 Years. 



Tn the 24th Volume of the Transactions of the Society of 

 Arts, See. page 75, Mr. Salmon, in a paper on the Ma- 

 nagement of Fir Woods, says, t( the distance of trees from 

 each other should be one-fifth of their height/* At that 

 distance, which is probably sufficient for fir trees, the fol- 

 lowing will be the number ofi an acre, and the number to 

 be cut out at the ages and heights under mentioned, and the 

 number of feet they will then contain in the bole, when 

 measured to the top of the leading shoot. These tree* are 

 supposed to increase twelve inches in height, and one in 



circumference, 



