A ]\I E R I C A N SYLVICULTURE 



A. The underwood: 



I. Species: Tlie species foiming the underwood must combine 

 natural sprouting capacity with shade endurance. On good soil, a 

 smaller amount of both qualities is required. Excellent species for 

 underwood are Basswood; Chestnut; Gum; Hornbeam; Calmia and 

 Rhododendron; on strong soil, Ash and Hickory; underneath a light 

 overwood also Oak. 



II. Purpose: The underwood sujijilies or may supply 



a. Companions for the younger age-classes of the overwood, 

 causing them to form clear boles; 



b. Protection of the soil, enriching it by its humus; 



c. Firewood and small timber; also tanning material. 



The underwood yields a dii'ect revenue only in case " c." Ob- 

 viously, where there is no market for firewood or small timber, the 

 underwood is only indirectly useful. 



III. Formation: For diameter, vitality and number of stumps 

 also for manner and season of cutting, the remarks of Par. LXVIII. 

 A. (about coppicing) hold good. 



B. The overwood: 



I. Species: The species forming the overwood should be storm- 

 firm and small crowned. Light demanders are usually preferred. 



Yellow Pines produce wide-ringed timber on strong soil and 

 suffer from sleet. Good species are: ^^^ute Oaks, Red Oak, 

 Hickory, Walnut, Yellow Poplar, Black Cherry, Locust, Larch, etc.; 

 on poorer soil Yellow Pines and Long-leaf Pine (over Black Jack). 



II. Age-classes: The number of age-classes in a normal over- 

 wood equals the fraction 3. wherein 



R represents the length of the rotation in the overwood, and 

 r represents the length of the rotation in tlie underwood. 

 The normal difference of age between consecutive classes is " r " 

 years. 



III. Normal formation: Tlie overwood is composed of "stand- 

 ards " regenerated, at the year of coppiced underwood, from self- 

 sown seed falling from the overwood or, in the cultured forest, from 

 planted seedlings. The seedlings of the overwood grow up im- 

 merged and often badly endangered in the new underwood. ^\Tlen 

 this is coppiced at the age of " r " years, an impixjvement cutting 

 takes place simultaneously removing misshapen or damaged stand- 

 ards of the various older classes as well as the weaklings in the 

 youngest class. By this improvement cutting the leaf canopy of 



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