THE AKT OF THE SECOXD GROWTH 



It is often suflicient for the increase of an aristocratic regenera- 

 tion to break or reduce tlie humus formed underneath the shrubbage. 



B. The battle against weed trees trying to propagate 

 their kind in tlie forest is usually more difficult to win than that 

 against shrubs since the progeny of weed trees does not stop to 

 compete with aristocrats after the thicket stage. The forester must 

 carefully gauge the chances for a final victory — usually a partial 

 victory — of the aristocrats, footing on a knowledge of their relative 

 height growth and their relative shade endurance. 



Weed trees might be prevented from successful seeding by: 



I. Deadening or stump peeling. 



II. Actual removal (unless resulting in rank stoolshoots). 



III. Sudden exposure of young progeny to draught or frost. 



IV. Maintenance of a dense humus, or of a dense leaf canopy. 



V. Pasturage. 



YI. Stopping all logging operations during seed years of the 

 weed-tree species. 



VII. Fire. 



Any of these remedies will answer on a regeneration area pro- 

 vided that it inflicts greater damage on the weed trees than on 

 the aristocrats, and that the success is fully commensurate to the 

 expense. 



A careful choice of the type of regeneration (cleared, shelter- 

 wood, and advance growth types in compartments, strips, groups 

 or patches) is, however, tj^ie best weapon in the hands of the forester 

 against mobbish usurpation. 



The time may come when the forester will avail himself of 

 plagues of fungi, vertebrates and insects in the struggle against 

 weed trees. 



Obviously, where the logger, followed by fires, removes every 

 vestige of the aristocracy and every chance for its reproduction on 

 deteriorated soil, there the sylvan battle is lost for the forester 

 before it is begun. 



Frequently in nature's economy and ecology a crop of weed 

 trees (Birches, Cottonwoods) intervenes between two generations of 

 aristocrats. This " rotatiort of crops " resembles that of agricul- 

 ture, and is hard to explain. Attempted explanations are: Exhaus- 

 tion of soil in mineral matter required by the previous species. 

 Presence of baccilli, bacteria, fungi, insects, etc., inimical to the 

 previous species. 



143 



