AMERICAN SYLVICULTURE 



Paragraph LI. The shelterwood selection type 

 of natural seed regeneration. 



This type srarcely exists in a pure form. Wliere it exists, it 

 is invariably bastardized with the cleared selection or the advance 

 growth selection type of natural seed regeneration. 



The pure type would imply the immediate development (or 

 rather the simultaneous development) of a seedling growth in the 

 very year (a seed year) in which the individual trees — very irregu- 

 larly, very scatteringly, on the basis of their lelative maturity — 

 are selected for removal. 



"Wliere the removal leaves a blank, tliere we meet the cleared 

 selection type. 



"Where the removal allows an advance growth already at hand 

 to fill the gap, there Ave meet the advance growth selection type. 



The premises for the shelterwood selection type are identical 

 with those for the cleared selection type and for the advance growth 

 selection type. 



Paragraph LII. Types in which lumbering fol- 

 lows natural seed regeneration. 



In these types of natural seed regeneration — so-called advance 

 growth types — no tree is removed unless its foot be already sur- 

 rounded by a young progeny of desirable character which has pre- 

 viously developed beneath the parent's or step-parent's leaf canopy. 



The case of exceedingly fertile soil and the case of step-parents 

 having a light leaf canopy excepted, none but absolute shade bearers 

 can be propagated by this type. So e. g., Hemlock, Fir, Beech, 

 Maple, Lawson's Cypress, Western Red Cedar. 



In the Lake States, White Pine is found as a regeneration 

 formed in advance beneath mature Norway Pines acting as step- 

 parents (advance growth group type). 



In the Adirondacks, Spruce regenerates similarly underneath 

 mature Cottonwoods acting as step-parents or, on very fertile soil, 

 selectionwise beneath Beech, Maple and Birch. 



Striking it is that species not absolutely shade enduring are, 

 in many a case, loth to be regenerated, as an advance growth, at 

 the feet of their actual parents, whilst willing to be suppressed 

 beneath step-parents of apparently similar density of foliage 

 (Yellow Poplar at Biltmore underneath Oak or Short-leaf Pine; 

 Spruce underneath Cottonwoods). 



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