ITS AIMS AND METHODS. 19 



production of fine trees by permitting the growth 

 of their lower branches. These, of course, interfere 

 with the growth of the reserve trees themselves as 

 well as with the young trees between them. Judi- 

 cious pruning can obviate this difficulty. 



Classification of Forest Trees according to Age. The 

 technical names by which reserve trees are known 

 vary in different regions. For our purpose it will be 

 best to divide the life of a forest tree into four prin- 

 cipal periods, designated as follows : 



1. Young, up to about forty years. 



2. Middle-aged, from forty to eighty years. 



3. Old, from eighty to one hundred and fifty 

 years. 



4. Very old trees, whose number is rapidly di- 

 minishing, may be called Veterans. 1 



These divisions are not, of course, absolute, as it is 

 often difficult to determine, even approximately, the 

 age of a standing tree ; and the forester must use 

 considerable judgment in the application of the fol- 

 lowing rules : 



1. The head of the young tree should be egg- 

 shaped or elongated oval (Fig. 12), and well balanced 



1 The technical terms employed in France to designate trees of the 

 four classes into which forest trees are generally divided, Bali mm, 

 Modeme, Ancien, and Vieilles&orces, have no equivalent as yet, and are 

 not well translated into English. The term " Baliveau " is also some- 

 times applied to reserve trees of any age left after the first cutting off 

 of a plantation, and such trees are then called " Modernes " or 

 " Anciens," according as they have been allowed to remain after a 

 second or third cutting of the coppice. c. 8. s. 



