A il E R I C A X SYLVICULTURE 



mother, for its best development. Spruce under Fire Clierry, White 

 Pine imder Cottonwood, Engelmanns Spruce under Aspen are ex- 

 amples for this phenomenon. 



Paragraph XLVIII. The shelterwood compart- 

 ment type of natural seed regeneration. 



A. This type is characterized by the uniform manner, 



in which lumbering and regeneration proceed over large areas. 



This uniformity is possible only in somewhat even-aged tracts. 

 Great difficulties are experienced in mixed forests, owing to the 

 difference of light requirements. 



The fixed conditions inviting the forester to adopt this type 

 are of a rather rare character, almost absent from primeval woods. 

 'Ihe education value of this type, however, is unparalleled. 



B. Actual application: Shade bearers are better adapted to 

 this type than light demanders. Beech is usually treated under this 

 type; Maple and Ash frequently so; Oak largely in France, rarely 

 in Germany; Fir and Spruce in parts of the Black Forest; Pine in 

 the old country but rarely owing to its demands on light. 



This " military " type was created by George L. Hartig, toward 

 the end of the eighteenth century. It was considered the ideal 

 type of regeneration up to about 1875. It is now far from being 

 abandoned, maintaining its role as the most commonly used type 

 of seed regeneration, although usually bastardized, in modern times, 

 with the strip and the group type. 



C. Advantages: 



I. Thorough protection of the soil, of its productive capacity 

 and its porosity. 



II. Small risk of utter failure. 



III. Large tracts taken in hand at one and the same time. 



IV. Methodical, military manner of proceeding which facili- 

 tates instruction of the staff of rangers and proper execution of 

 orders by the staff. 



V. Mother trees, standing above the young growth in isolated 

 position, yield an extra-increment of high value ("light increment"). 



VI. Young growth is well protected against climatic adversities. 



D. Disadvantages: 



I. Difficulty of obtaining a desired mixture of species in the 

 young growth. 



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