SUCCESSION OF FOREST TREES. 



39 



winged seeds are blown long distances — sometimes as 

 mncli as several miles. 

 This explains how certain 

 kinds of trees, like the 

 Grray Birch and the White 

 Pine, grow uj) in the mid- 

 dle of open pastnres, and 

 how others, such as the 

 Lodgepole Pine, cover 

 great areas, far from the 

 parent trees, with young 

 growth of even age. 



THE SUCCESSION OF 

 FOREST TREES. 



Such facts help to ex- 

 plain why, in certain 

 places, it happens that 

 when Pines are cut down 

 Oaks succeed them, or 

 when Oaks are removed 

 Pines occupy the ground. 

 It is very often true that 

 young trees of one kind 

 are already growing un- 

 noticed beneath old trees 

 of another, and so are 

 ready to replace them 

 whenever the upper story is cut away. (See fig. 33.) 



PURE AND MIXED FOREST. 



The nature of the seed has much to do with the distri- 

 bution of trees in pure or mixed forest. It is the habit 

 of some trees to grow in bodies of some extent contain- 



FiG. 37.— Pure forest of White Cedar 

 near Toms River, Xew Jersey. 



