222 



WOOD AND FOREST. 



fall, unless carried down hill by gravity or by water, or scattered by 

 birds and squirrels. 



Trees with winged seeds, however. Fig. 68, as bass, maple and 

 pine, or with light seeds, as poplar, often have their seeds carried by 

 the wind to great distances. 



Again some trees, as spruce, are very fertile, while others, like 

 beech, have only occasional seed-bearing seasons, once in three or 



Fijj. 67. Sprouting" Reilwood Stumps. Glen Blair, Calif. 

 i'. S. Forcsi Service. 



four years. Willow seeds lose their power of germination in a few 

 days, and hence, unless they soon reach ground where there is plenty 

 of moisture, they die. This is why they grow mostly along water 

 courses. On the other hand, black locust pods and the cones of some 

 pines keep their seeds perfect for many years, often until a fire bursts 

 them open, and so they live at the expense of their competitors. 



