SYLVICULTURE 



felling, and unless the timber obtained is carried out either by hand, 

 or on high wheel trucks, or on a heavy cover of snow protecting 

 the advance growth. Under any circumstances, fellings during the 

 perioa of vegetation must be avoided. 



III. Advance growth suddenly exposed to the full influence of 

 sun, rain, snow, sleet, etc., is apt to suffer in case of sensitive species. 



IV. A minute system of permanent roads is required, the ad- 

 vance growth usually appearing in groups or patches. 



V. If the pure types of advance growth n. s. r. were strictly 

 adhered to, a regulation of the annual cut according to the conditions 

 of the market would be difficult to obtain. Hypermature trees 

 would have to be left everywhere — merely because young growth 

 if often slow to form on their feet. 



In such cases, artificial preparation of a seed-bed (f. i., by un- 

 covering the mineral soil) seems absolutely required, so as to ex- 

 pedite the formation of advance growth. 



If the leaf canopy overhead is opened at the same time by fell- 

 ing ■operations, the types bastardize with the shelterwood types of 

 n. s. r. 



According to the extent of the area covered by an advance 

 growth of suitable cliaracter we distinguish between: 



a. Advance growth compartment type of n. s. r., the areas uni- 

 formly covered by advance growth measuring from twenty to one 

 hundred acres (rare). 



b. Advance growth strip type of n. s. r., the areas uniformly 

 covered by advance growth appearing as strips measuring up to 

 500 feet in breaath (very rare).- 



c. Advance growth group type of n. s. r., the groups covered by 

 advance growth having an extent of from one-tenth to three acres 

 (frequent). 



d. Advance growth selection type of n. s. r., the young seedlings 

 and saplings appearing in scattered and small patches (very com- 

 mon). 



Under "advance growth" is understood an aggregate (small or 

 large) of seedlings or saplings belonging to a desirable species and 

 formed without any human intention or attention, solely by nature, 

 beneath a totally or partially untouched leaf canopy overhead. 



Spreading advance growth appearing in bunches or groups can 

 be doctored up with axe and brushhook and machetes, by an appli- 

 cation of " hairdressing." 



Where the advance growth is not freed, by one single operation, 

 from the superstructure of parents and step-parents overhead, the 

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