STORAGE ROOMS 
73 
great deal. They have a special arrangement 
to prevent too much transpiration. The leaves 
can make food only during the warm sunny 
months. As the weather gets colder, they work 
more and more slowly, and at last stop alto¬ 
gether. Even though they are not working 
they continue to send off water. Moisture is 
scarce in cold weather and the tree cannot afford 
to lose any. In order to save its precious water 
supply, the tree drops its leaves. During the 
winter the tree can get along better without 
them because they do not work, and they are 
wasteful of moisture. When they are gone, 
most of the water is safe. It cannot escape in 
any other way. The bark is too thick and 
rough to allow any moisture to pass through. 
When spring comes again with its rain, new 
leaves come out and carry on the work of 
making and transpiring moisture. 
The chief business of a flower is to produce 
seeds, to see that they are safely pollinated and 
ripened in order that they can grow into new 
plants. The parent plant takes great care to 
Trees drop 
their leaves 
to save water 
