SYLVICULTURE 



year (a seed year) in which the individual trees — verj' irregularly, 

 very scattei'ingly, on the basis of their relative maturity — are selected 

 for removal. 



Where the removal leaves a blank, we meet the cleared selection 

 type. 



Where tlie removal allows an advance growth already at hand 

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



The premises for the shelterwood selection type are identical 

 with those for the cleared selection tj'pe and for the advance growth 

 selection type. 



Paragraph LII. Types in which lumbering follows after n. s. r. 



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, absolute shade bearers only can 

 be propagated by this type. So f. i.. 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 Adirondaeks, 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 be- 

 neath step-parents of apparently similar density of foilage (Yellow 

 Poplar at Biltmore underneath Oak or Short-leaf Pine; Spruce 

 underneath Cottonwoods). 



Species regenerating under their own kin resemble altricial (nidi- 

 cole) birds; species avoiding parental superstructure might be likened 

 to precocial (nidifugal) birds. 



The chances for successful regeneration in tliose types seem ex- 

 cellent. Still, the following points must not be lost sight of: 



I. Advance growth badly suppressed for a long time is fre- 

 quently so badly crippled that it fails to recover within a reasonable 

 number of years. 



II. The advance growth is badly smaslied by and during the fell- 

 ing operations, unless the mother trees are pruned and lopped before 



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