224 Forestry Quarterly. 



other deficiencies are charged, especially greater liability to the 

 destructive attacks of the pine fungus, Dasyscypha, than the 

 native trees. Since about 50,000 acres of such plantations from 

 the German seed exist, the damage must be considerable. 



The article on thinnings does not bring results, since the sample 

 areas are only ten years old; but the whole history of thinnings 

 and various methods are described, A new classification of stem 

 classes for experimental areas is proposed, namely in part by the 

 place in the crown cover, in part by the form of crowns, and in 

 smaller part by the form of the stems themselves- The height to 

 which crowns reach the author calls "crown-layer." The crown- 

 layer of the subordinate stand as a rule has been found to lie at 

 about 50 per cent, in pine often 60 per cent, of the height of the 

 dominant. The upper half or two-fifths of the height may then 

 be divided into three, about equal layers, corresponding to domi- 

 nant, codominant and dominated tree classes. 



The wavy outline of the cover of a regular stand is due mainly 

 to the two upper layers, which are formed by groups or single 

 trees in mixture. In experimental areas, if the upper layer I 

 sinks to the height which in the rest of the stand was occupied by 

 layer III, this must be recognized as the sample area limit. The 

 crown layers III and IV sometimes, especially in light needing 

 species like pine, merge so into each other that it is difficult to 

 diflferentiate, nevertheless, where possible the dififerentiation is of 

 use. Crown layer I, then, is formed by the highest stems ; II, 

 by the somewhat lower stems with less fully developed crowns, 

 and not rarely slenderer trees, the height coming to about 5/6 of 

 that of I; the layer of III reaches to about 2/3 of I, indicated by 

 shortened leaders — laggards ; the suppressed trees reach up to 

 50 to 60 per cent of the layer I, and to these are assigned also 

 trees of the same height standing in openings. Besides, there 

 may be recognized overholders, single trees more than 40 years 

 older than the main stand ; and underwood, whatever is below 

 half the height of I. 



Each crown layer is then according to crown and bole develop- 

 ment distinguished into tree classes, reserving the designation 

 stem classes for diameter distinctions- The tree clases then are: 

 a. one sided crowns; b. predominant, broad-crowned ("wolves") ; 

 c. very crooked or branchy, or double leaders and other faulty 

 forms ; d. generally narrowed-in and hence damaged crowns ; e. 



