THE WON DEES OF VEGETATION. 153 



of Beque, which is called by the inhabitants of the 

 country " the stable of the chamois," because it serves 

 as a shelter for these animals during winter. It meas- 

 ures nearly 24 feet in circumference and 15 feet at the 

 first branches. In spite of its magnificent growth and 

 still verdant foliage, it is said to be 1,200 years old. 



At first -sight it seems astonishing that the appear- 

 ance of a tree should enable us to determine, at least 

 approximately, its age, and yet the explanation is very 

 simple. 



Every year a new layer of wood forms itself upon 

 the tree, and when the trunk is sawn through the 

 number of years it has lived is indicated by the 

 number of concentric rings ; since each ring in the 

 wood represents the new layer which has been formed 

 that year. A tree that shows a hundred rings, is 

 generally regarded as having lived a century. It is 

 by these observations upon the trees themselves or 

 upon others of the same species, and by ingenious de- 

 ductions, that botanists succeed in determining the age 

 of trees. 



The plants which in all parts of the world acquire 

 the most remarkable size are the yews, the chestnuts, 

 several bamboos, the mimosas, the cisalpinias, the fig- 

 trees, the mahogany-trees, the cypresses, and the wes- 

 tern plane-trees. We do not speak of the race of gi- 

 gantic trees in California, which surpass all others, and 

 the dimensions of which will be given in a future 

 chapter. 



