5 



the nnmber of stems would, of course, vary with the species and with other oircum- 



1st acre containing about 110 trees 20 years old, 



I'f " .. .. 120 „ 19 „ 



aid .. .. „ 130 „ 18 



f^ " » ,. 150 „ 17 „ 



5th „ „ „ 170 „ 16 „ 



6th „ „ „ 190 „ 15 „ 



7th „ „ „ 220 „ 14 



8th ,. „ „ 250 „ 13 „ 



9th „ „ „ 300 „ 13 „ 



^Oth 350 ., 11 „ 



11th „ „ „ 4! 10 ,. 10 „ 



12th „ „ „ 500 „ 9 



l^'h , 600 „ 8 „ 



J 4th „ „ „ 800 „ 7 „ 



l^th 1.000 „ 6 „ 



16th „ „ „ 2,000 „ 5 



H'^ ■' » .. 5'"00 „ 4 „ 



18th „ „ „ 10,000 „ 3 „ 



19th „ „ „ 20,000 „ 2 „ 



20th „ „ „ 40,000 „ 1 year old. 



Total 20 acres containing about 82,290 stems. 



In Bctnal practice we could not, of course, distinguish betwesn trees differing in 

 age by only one year. If the trees in such a forest as the above had to be counted, 

 they would be grouped in age-classes of, say, — 



This would not indicate whether the capital was properly constituted or not. 

 We could only say that the cron was complete, and that all stages of growth were 

 well represented ; for we cannot even approximately estimate the relative number of 

 trees in each age-class which ought to be found in an irregular forest. Indeed, the 

 relative proportion is constantly changing, and this fact is one of the chief diaw- 

 backs to the application of the selection method of working, and is the reason why 

 there are so many different ways of attempting to calculate the possibility of such 

 forests. Where tlie crops of different ages occupy distinct areas nothing is simpler 

 than to measure these areas and to arrive at a coiTect estimate of the quantity of 

 material the forest can, and ought to, produce ; but, in the case of irregular crops, we 

 can neither measure the area occupied by each age-class, nor derive by other means, 

 from the nnmber of trees found to be growing in the forest, absolutely accurate 

 information as regards the sufficiency or otherwise of the capital. 



Summary of the chief points to be remembered with regard to 

 the constitution of the forest capital. — If we suppose that the 

 darkened rectangles in figs. Nos. 1 and 2 represent the 

 volume of material produced in each coupe in any given 

 year, the chief facts to he rememhered with regard to the 

 constitution of the forest capital may he readily understood. 



