66 CHRISTISON—-OBSERVATIONS ON 
B. Annual Rate and Range of Girth-increase in 
Deciduous Trees at Different Ages. 
The rate of girth-increase in trees must evidently be 
affected by various conditions of locality, such as soil, shelter, 
crowding or the reverse, the effects of which cannot always be 
easily eliminated. But another condition of no little influence 
is age, for there is a natural rise in the annual increase from 
infancy through youth, and a subsequent decline, the limits of 
which in the different species have not been, perhaps cannot be, 
determined. To get rid in some degree of this last cause, I 
have divided my trees in Tables I. to V. under five categories, 
according to their size. Usually only the quickest growers have 
been given, as being more likely to be representative of the 
normal characteristics of the species than such as proved 
comparative failures. Some have been under observation for a 
period sufficiently long to appear in more than one of the 
categories. 
Leaving the Tables mainly to tell their own tale, attention 
may be directed to a few of the chief points in each of the 
categories. 
ANNUAL RATE. 
