182 OUTLINES OF FORESTRY. 



catch in the fur of animals or in the plumage of 

 birds, and in this manner are often carried to 

 distant regions. 



Some seeds, which are swallowed whole by 

 birds or other animals, often pass out uninjured 

 by the process of digestion at localities far distant 

 from where they were produced. 



Civilized man either purposely or accidentally 

 carries seeds from one locality to another. 



It sometimes happens that plants introduced 

 into a particular section of country from a dis- 

 tant land find the new soil and climate so favor- 

 able to growth as to completely drive out and 

 exterminate domestic species. 



The germs or seeds of plants often exhibit a 

 remarkable tenacity of life under certain circum- 

 stances. Grains of corn or wheat taken from 

 Egyptian mummies have grown and borne fruit, 

 notwithstanding their centuries of rest. 



In a densely-wooded section of country the 

 ground is often so thickly covered by trees as to 

 exclude all other forms of vegetable life. When, 

 however, the removal of a few trees lets in the 

 sunlight and heat, the seeds, which were possibly 

 slumbering in the ground for centuries, at once 

 spring into active life. 



