THE LIFE OF THE TREES 19 



Crisp and dry the leaves fall. Among the crystals and 

 granules that remain in their empty chambers there is little 

 but waste that the tree can well afford to be rid of — sub- 

 stances that have clogged the leaf and impeded its work. 



We have been mistaken in attributing the gay colors of 

 autumnal foKage to the action of frost. The ripening of 

 the leaves occurs in the season of warm days and frosty 

 nights, but it does not follow that the two phenomena be- 

 long together as cause and effect. Frost no doubt hastens 

 the process. But the chemical changes that attend the 

 migration of the carbohydrates and albuminous materials 

 from the leaf back into twig and trunk and root for safe 

 keeping go on no matter what the weather. 



In countries having a moist atmosphere autumn 

 colors are less vivid. England and our own Pacific Coast 

 have nothing to compare with the glory of the foliage in the 

 forests of Canada and the Northeastern states, and with 

 those on the wooded slopes of the Swiss Alps, and along the 

 Rhine and the Danube. Long, dry autumns produce the 

 finest succession of colors. The most brilliant reds and 

 yellows often appear long before the first frost. Cold rains 

 of long duration wash the colors out of the landscape, 

 sometimes spoiling everything before October. A sharp 

 freeze before the leaves expect it often cuts them off before 

 they are ripe. They stiffen and fall, and are wet and limp 

 next day, as if they had been scalded; all their rich cell sub- 

 stance lost to the tree, except as they form a mulch about 

 its roots. But no tree can afford so expensive a fertilizer, 

 and happily they are not often caught unawares. 



Under the trees the dead leaves lie, forming with the 

 snow a protective blanket for the roots. In spring the 

 rains will leach out their mineral substance and add it to 



