332 Forestry Quarterly. 



height growth and site conditions. This shortening of the growth 

 rate of the main axis is accompanied by increase of the form factor 

 and hence also with same height and density poorer sites produce 

 more cylindrical stems. The changes in crown form of the various 

 species are described in detail. 



The author then proceeds to the discussion of Erziehungshiebe, 

 thinnings, the object of which, he repeats, is to secure in a given 

 time the highest attainable values with due regard to expenses. 



Thinning in the Subdominant (Niederdurchforstung), removing 

 only dead and dying, neglects the time element and on poor sites 

 fails to secure results altogether, because no dominant growth is de- 

 veloped. 



Thinning in the Dominant (Hochdurchforstung) contemplates 

 the growing of selected trees, which in number may be as many as 

 can finally occupy the area with normal crown cover. Specially 

 selected for their good form, this elite is to specially cared for from 

 early youth by giving them light and room for development as need- 

 ed, keeping the secondary growth for filler and nurse crop. The ob- 

 ject of securing stout material in shorter time is attained only under 

 certain conditions, for even this method may not claim general ap- 

 plication, and the author proceeds at length to discuss its limitations. 



The first difficulty is to determine upon a number of the elite, 

 which must vary according to species, site, rotation, etc., and re- 

 quires knowledge of the losses that must occur. This, however, is 

 not so difficult since in time corrections and reductions can be made 

 as they appear desirable. The individual care, however, must be 

 costly and, while theoretically the proposition is tenable, practically 

 and financially it may not be, and in large administrations almost 

 certainly will not be. 



Additional objections come from considerations, of characteris- 

 tics of species in shaft form, height growth and of form of stand. It 

 is prescribed to care for the elite by openings around their crowns 

 suitable to their development. Now, as shown, in deciduous trees 

 such openings tend to produce unfavorable effects in shaft form 

 unless they are made very moderate. Such moderate openings, how- 

 ever, are only possible in younger years. The older the stand, the 

 more difficult to open up around a dominant stem in a given, mod- 

 erate degree. The removal of a neighbor is apt to make too big a 

 hole, and the effect will be opposite from the desired. In a pole 



