88 TRANSACTIONS AND PEOCEEDINGS OF THE [Sess. lxii. 



menon must not be mistaken for the bending of trees on 

 exposed situations by the prevailing winds. 



On the edges of dense woods and forests, trees have 

 most branches on the side turned to the light ; fewest on 

 the side next the mass of the forest. These conditions 

 hold good for the specimens under consideration, therefore 

 we find the greatest development of branches on the same 

 side as the greatest radial increment. 



Now, since the elaborated sap or digested food of the 

 tree is made in the green leaves, it evidently descends the 

 tree mostly by the bast of the side on which it is manu- 

 factured, and thus brings about the radial increment of 

 wood on that side. 



The breadth of the annual rings showed that most of 

 the trees had reached the limit of most active growth in 

 girth at the ages of 30 to 50 years, but in some cases 

 the growth was continued long beyond this age, with only 

 a very gradual decrease of vigour. 



Among the broad annual rings in the older parts of the 

 tree much narrower rings were occasionally found ; in the 

 same way, broad rings occasionally among the narrower 

 rings of the younger wood. It is almost impossible to 

 determine definitely the causes which bring about such 

 variations from year to year. In the absence of a detailed 

 history of each tree, the question of thinnings must be left 

 out of account, although it is well known that a judicious 

 tliinning affects most beneficially tliose trees that are thus 

 more exposed to the light and heat of the sun. 



The trees in question, to all appearance, had grown with 

 plenty of space all round, and had not been forced into 

 the pole-stage, according to tlio principles of modern 

 sylviculture. 



Again, the frequency of tlie variations, al)ove referred 

 to, shows that periodic thinnings could not be the sole 

 cause. 



Soil and situation were constant factors througliout, 

 except tliat, as growLli in heiglit proceeded, an increasing 

 density of leafy canopy would be the result, but this 

 would not account for the variation. 



Frequent storms might, by removing certain trees, 

 expose the survivors to greater light, but storms of this 



