CONTEOL OF DISEASE. 63 



leave only sound seed trees and sound reproduction in 

 healthy surroundings. It also makes possible utiliza- 

 tion of merchantable timber left in undesirable trees, 

 which would otherwise go to waste. 



One other point should be borne in mind by every 

 forest officer who has to do with marking timber. 

 Seed trees left for reproduction should be sound and 

 not too old. Neither in animal nor in plant life can 

 healthy, thrifty offspring be expected from diseased, 

 weak, or aged parents. The future of the forest de- 

 pends very largely upon the right choice of seed trees. 



