Reproduction and Growth 



Species in this forest type differ in shade tolerance, longevity, and growth 

 rate. Yellow birch tolerates shade moderately well but usually has the 

 slowest growth. White ash and red maple are also intermediate in shade 

 tolerance but have moderately fast growth rates. Paper birch is one of the 

 fastest growing commercial species but the typical variety is short-lived and 

 very intolerant of shade. Sugar maple, beech, hemlock, and red spruce are all 

 shade-tolerant, long-lived species. Sugar maple and beech have moderate 

 growth rates, whereas hemlock and red spruce are slow growing. Sugar maple, 

 beech, and hemlock are the principal components of the northern hardwood 

 climax forest (Society of American Forester 1967). 



The highly shade-tolerant sugar maple and beech dominate the understories of 

 most northern hardwood stands. In contrast, yellow and paper birches need 

 some overhead light and seedbeds of humus or mineral soil for their early 

 establishment and development (Fowells 1965). Paper birch must become 

 dominant in the stand early in life in order to survive to maturity. 



Management Methods 



Management methods require that a landowner must first decide whether he wants 

 his growing stock to yield top grade products such as veneer logs, sawlogs , 

 and millwood or to yield mostly pulpwood, fuelwood, or other less-valued 

 products. A second basic decision he must make is whether to manage for a 

 high proportion of shade-tolerant species, intermediates, or intolerants. 

 This would have a controlling influence over the silvicultural system used. 



Management of uneven-aged stands . Management by uneven-aged stands 

 implemented through selective cutting of individual trees or harvesting of 

 trees in groups of two or three, is recommended for growing a high proportion 

 of shade-tolerant species (i.e., sugar maple, beech, hemlock, and spruce) 

 (Leak et al. 1970; and Tubbs 1968). Selective cutting will produce veneer 

 logs, sawlogs, and millwood, with pulpwood as a byproduct. The public 

 generally accepts selection cutting esthetically because a residual stand 

 always covers the site and disturbance from logging is not as apparent. 



To achieve maximum yields, the cuttings are repeated at 10-to 20-year 

 intervals. To develop and maintain a balanced stand structure, a deliberate 

 attempt must be made to mark trees in all diameter classes for cutting. This 

 is not always done because diameter-limit cutting is practiced extensively in 

 the maple-beech-birch forest type in the characterization area. 



In many of today's uneven-aged stands, past preferences for certain species in 

 cutting operations and heavy mortality or deterioration in some species (such 

 as beech) from disease attacks have caused considerable variation in 

 structure, stocking, composition, and grade. It may take three or more cyclic 

 cuts (over a given rotational cycle) to improve the productivity of such 

 stands. Yields from improvement cuttings may contain 55% or more low-value 

 products (Filip 1967). In subsequent cuttings the yield should be mostly top- 

 grade products (see "Fuelwood," below). 



19-15 



