PLANT ECOLOGY 



CHAPTER I 

 INTRODUCTION 



INIan could not live without plants. They are the source of all 

 food, practically all fuel, and all important natural fibers except 

 wool and silk which are obtained from animals that feed upon plants. 

 They are also the direct source of rubber, paper, most drugs, and 

 very many other products without which the progress of civilization 

 would have been absolutely impossible. There can be no question 

 of the desirability of studying objects that are of such very great 

 importance to our health and comfort, indeed to our very existence, 

 as are plants. 



1. The Necessity of Studying Plants in the Field.— Plants have 

 been objects of study for a very long time. Too often, however, the 

 studies have been confined largely to laboratories and books while 

 field studies have been neglected. 



The only practical way to become well acquainted with plants 

 is to study them where they grow. The botanist who has limited 

 himself largely to laboratory and library studies is usually consider- 

 ably at a loss when he faces a field problem. He does not recognize 

 the different kinds of plants nor does he know where to look for 

 particular kinds nor why these kinds cannot be expected to grow 

 in certain types of places. jNIany of the most important plant 

 problems awaiting solution at the present time, problems that are 

 of vital importance to the world's food supply or to the supply of 

 lumber and other forest products, are field problems. It is, there- 

 fore, essential that those who are training themselves along botan- 

 ical lines should place a reasonable emphasis u])on field work. 



There is another reason for studying plants in the field that must 

 recei\e consideration. This has to do with the esthetic value of 

 plants. None of us would care to live in a house around which 

 there were absolutely no plants. Whenever we think of a beautiful 

 home or a beautiful city we think of one that is well supplied with 

 trees, shrubs, grass and flowers. The beauty of plants in such 



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