120 Our Field and Forest Trees 



richer soil. So through most of the eastern United 

 States, when the pine forest is felled, an oak for- 

 est grows. 



Roots sometimes follow the water in a wonder- 

 ful way. If a tree stands near the edge of a pond. 

 Its roots are apt to grow toward the moister soil, 

 so that those on one side of the tree will be much 

 larger than those on the other. 



In the arid lands of the far Southwest there is 

 a bush called the mesquite, which turns its roots 

 so accurately toward underground water that it 

 shows the Mexican farmer where to dig for a 

 well. He follows these roots as a guide, and 

 sometimes, in their quest for water, they reach out 

 for sixty feet or more. 



Our native trees, though they live where water 

 is less precious, feel after it and find it with like 

 perseverance (Fig. 31). 



If a tree grows close to a pond or stream, so 

 that part of its roots reach out into the water, 

 they develop into what are called water roots. 

 These have no root-hairs. They need no special 

 arrangements for taking in water — their whole 

 surface drinks. They are smooth whitish threads 

 like those which dangle from hyacinth bulbs when 

 they are grown in water. Sometimes when a tree- 

 root enters a drain it puts forth such threads in 

 great numbers, so that the drain becomes filled 

 up and choked. 



Stumps left by the woodcutters often sprout 



