SYLVICULTURE 



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

 overwood also Oak. 



II. Purpose: The underwood supplies 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 direct 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: White 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 overwood 



equals the fraction ^L wherein 



r 



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

 r represents the length of the rotation in the underwood. 

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



years. 



III. Normal formation: The 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 immerged and 

 often badly endangered in the new underwood. When this is cop- 

 piced at the age of r years, an improvement cutting takes place 

 simultaneously removing misshapen or damaged standards of the 

 various older classes as well as the weaklings in the youngest class. 

 By thi? improvement cutting the leaf canopy of the standards, which 

 has had ample chance of enlargement during the past r years, is cut 

 back to a normal limit. 



The older an age-class is, the smaller is the number of its con- 

 stituents. 



C. Abnormal formation of overwood and underwood: 



A normally proportioned and normally formed overwood is never 

 found. Deficiencies lie 



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