64 



A PKIMER OF FORESTRY. 



air of the forest has less capacity for taking up water 

 vapor than that of the open countiy. It is also qui- 

 eter, which means that the winds are less active in 

 replacing saturated air with air which can still take up 

 more water. The forest acts powerfullj^ in checking 

 the force of the wdnds because the elastic swaying of 

 the twigs and branches is a very effective hindrance to 



Fig. 41.— a windbreak. California. 



the movement of the air. Strong winds, although they 

 are often dangerous in themselves, do most harm b}^ 

 dr34ng up the moisture in the soil and in the plants 

 which grow from it. Thousands of miles of wind- 

 breaks have been planted by farmers in the western 

 parts of this country to protect their crops and homes 

 ag'ainst the wind. These windbreaks serve a most use- 

 ful purpose, but they are naturally far less effective in 



