20 



scattered about in patches, the growing stocJc "would still be- 

 tbe same, and it would still be true that, in order to fell 

 every year an acre of forest 20 years old, there must exist 

 on the ground a complete scale of growths, each covering^ 

 le acre and aged from 1 to 20 years. 



Carrjing tbe irregularity of distribution still further we 

 arrive at the condition of a forest such as the selection method 

 of working leads to. The different age-classes are so inter- 

 mingled that the trees overtop one another, and we practi- 

 cally find stems of all ages on any and every area of appre- 

 ciable size. We cannot measure the area occupied by each 

 class ; but we know by analogy that the classes must exist in 

 regular gradation of ages if the forest is to furnish uninter- 

 ruptedly its full yield. 



3. Information afforded by tlie number of trees of each age- 

 class.— As regards the number of trees constituting the grow- 

 ing stock ia each age-gradation of a normal forest, it need 

 hardly be explained that, although the areas occupied by 

 each age-class may be equal, the number of trees in each' 

 age-class are very far from being the same. There are in- 

 finitely more stems in a young crop, if complete, than in 

 an older crop, occupying the same area, but containing trees 

 with large crowns. 



In fact, if we were actually to count the stems, from the seedling to the mature 

 tree, on each acre in a properlv constituted crop such as that shown in fig. No. 1, the 

 result, we may suppose by way of illustration, would be something as follows, though 

 the number of stems would, of course, vary with the species and with other circuift'- 



stances: — 



1st acre containing abcu': 



2nd „ 



3rd „ „ „ 



4tu „ ,, „ 



6'll .1 » ,< 



6th „ „ „ 



7 th „ 



8th „ „ „ 



Sth .. 



10th „ „ „ 



lltt » 



12th „ 



13th „ „ „ 



14th „ „ „ 



15th „ „ „ 



16th „ 



17th „ „ „ 



18th „ ,1 



19th ,, „ ,, 



20th ., 



110 trees 20 years old. 



Total 20 acres coctaiuiug about 82,290 stems. 



