AMERICAl^ SYLVICULTURE " 



Paragraph LXIII. Pruning in seed forests. 



A. The object at stake might be: 



L I'loduction of logs free from knots, — especially free from 

 dead knots. Live or sound knots measuring one and one-quarter 

 inches in diameter affect the lumber price but slightly. The pre- 

 vention of dead knots is, therefore, most important. No topshoot 

 is formed without side shoots, and no section of a tree bole is 

 free from branches and free from branch knots. Hence the advisa- 

 bility of pruning the boles of such species which develop branches 

 of large diameter and of great persistence when dead. Branches 

 (excepting adventitious branches) invariably start from the central 

 core. 



II. Increased height growth. 



III. The production of cylindrical boles of a large form figure 

 (Pressler's law of bole formation). Obviously, objects "II" and 

 " III " are not obtained but by the removal of living branches. 



IV. The reduction of the shade falling on u young, promising 

 undergrowth. 



V. Tlie reduction of danger from fire in coniferous woods close 

 to public roads. 



B. Species: Hardwoods suffer less from the removal of 

 green branches than softwoods, (xreen branches of over five inches 

 in diameter should not be removed at all, except in case " IV," 

 owing to the certainty of subsequent disease. 



Oak heals best of all kinds the wound inflicted by pruning; 

 Ash is likely to split; Maple is slow in closing a woiuid; Birch soon 

 shows disease; Yellow Pine covers the wound quickly with rosin. 



C. Actual European practice: 



The practice restricts pruning to the object given under A. I., 

 and within that limit to: 



I. Dead branches. 



II. Polewoods forty years to sixty years old. 



III. Two log lengths from the ground. 



IV. The specimens presumably predestined to reach the end of 

 the rotation. 



Pruning extends to a height reaching up to forty feet, is done 

 by help of ladders, of a climbing apparatus (not climbing irons) 

 or of saws attached to very long polos. The best saw is the 

 " Alers " construction. 



In France, sharp, curved blades are preferred to saws, since 

 they produce a smoother cut. 



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