LEAVES ARE TREE ASH CANS 
than a shadow. All its vital parts have been pumped out 
before it was dropped. 
But the tree has done more than this. It has found 
that, during its summer housekeeping, certain materials 
have got in for which it had no use. During those 
months, if it is a big tree, it has been pumping up one 
hundred gallons of water a day from the roots and letting 
it evaporate from the leaves. This is a part of its process 
of manufacturing plant food. 
In this water there have been small particles of mineral 
substances that it has not been able to use. There is 
likely to be a good deal of lime in the tree that it does not 
want. There may also be a good deal of iron, or iron 
oxide. This is rust. It is also the substance which red¬ 
dens soil. 
The tree rushes these waste materials into the leaves 
it is about to drop. It dusts itself out and puts the waste 
into those leaf ash cans that are ready for the dump. 
Strangely, these waste products have a good deal to do 
with the color of autumn leaves. The red of them is due 
somewhat to the dryness or wetness of the season. Dry 
weather in the autumn produces brilliant foliage, and wet 
weather spoils it. In damp climates like that of England 
autumn is clothed in dull colors. 
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