334 Forestry Quarterly. 



formation of raw humus, light and rain reaching the soil move free- 

 ly. Grass and weeds, come in, to be sure, but soon vanish again. 

 General rules cannot be given for degree and time of this operation 

 any more than for the other modes, all depending on species and 

 form of stand. Some species must be forced from early youth to 

 grow straight and clear shafts, others do not lose anything by delay. 

 Each species makes different demands on degree of density for best 

 shaft development. In this respect the author places in series larch, 

 spruce, fir, birch, aspen, pine, alder, ash, oak, beech, the latter re- 

 quiring the densest stand, while the larch even in open stand will 

 develop good boles ; one thousand trees to the acre medium site of 

 the first, at least ten times for the last would be a desirable number. 

 For fir two thousand trees would still insure straight bole and suffi- 

 cient clearing. By starting plantations with the proper number 

 according to characteristics in the shaft formation of the species, the 

 necessity of thinnings may be avoided until a dominant growth is 

 clearly developed, and indicated by the crown form. This time comes 

 usually when the height growth begins to retard, and the earlier the 

 less danger there is of detrimental reaction on shaft form. Hence, 

 larch, spruce, fir should be kept open in youth, and later, when 

 height growth is finished, dense; pine and broad-leaf trees the re- 

 verse. 



Economy requires to avoid as much as possible the need of thin- 

 nings: the growing of pure, even-aged stands, properly started, will 

 under otherwise equal conditions produce the best financial results. 



The author then discusses in elaborate detail the methods of pro- 

 cedure under a variety of conditions for each of the principal Ger- 

 man species. 



To give a sample of the manner of treating the subject we select 

 the pine, as probably most nearly representing similar conditions to 

 our various yellow pines. 



The pine is the only conifer which as regards its needs in early 

 youth approaches the broad-leaved species: it must be kept dense. 

 On better sites it may be planted in more open position than on poor 

 sites, not over 1 m (3 1-4 feet) on the latter, 1.25 m (4 feet) on the 

 former. Natural regenerations or sowings should be thinned early. 

 During the clearing period it should be kept dense — the reverse of 

 spruce and larch — clear bole at the expense of diameter growth re- 

 quiring this. When the crown has decreased to one-third of shaft 



