Periodical Literature. 335 



length a severe thinning is indicated, reducing numbers to one-half, 

 which will rapidly close up. Then follows a longer or shorter per- 

 iod of rest and density until height growth begins to retard, when the 

 shaft form is completed, and thinning for diameter is required. A 

 secondary stand will then have formed, which is to be left at first 

 to help the clearing process but, when the young timber period is 

 reached, and the shaft form satisfactory, every laggard is to be 

 removed, and in even groups standing room for each is to be pro- 

 vided. But decidedly dominant trees even then must not be freed, 

 for it would require making larger holes in the crown cover than 

 can now be closed, and the trees would grow into spreading crowns 

 except on very good sites, and now the characteristic broad-leaved 

 and rounded crown forms, strong branches develop umbrella-shape, 

 and diameter growth proceeds with maximum rate. Thinning in the 

 dominant is not fitted for the pine, it induces sprawling, branchy 

 trees (Protzen). 



It is understood that the density of the first period must not be 

 continued so that the stand becomes stationary or the stems remain 

 so slim as to be endangered by snow pressure, etc. Such stands 

 must be gradually brought into more open position. 



It is difficult to avoid under this treatment the formation of an- 

 nual ring zones of varying width, less so, however, than with spruce 

 and fir, and a loss in quality need not be feared. 



On poorer sites the young growths can be kept more open, and 

 they require earlier interference as regards time, but at about the 

 same height. With pine the early education is decisive for shaft 

 form, while larch, spruce, fir may even in later life be forced to 

 clear their shafts. A pine growth grown up in open stand can not 

 any more be made to grow into technically valuable wood, for knotty 

 and rotten branch holes are too frequent. 



An indication for the time of thinning in the polewood is the leaf 

 fall. In the stage of densest cover the leaf fall, just as with the 

 spruce, on account of the dying branches, is more abundant and 

 ceases almost suddenly at the end of the clearing period, because the 

 living crown has then sunk to a minimum. After the period of max- 

 imum height growth the pine thins out naturally, and permits a 

 soil vegetation, yet even in old age it can spread its crown and 

 make it denser, the accretion, however, does not react much to the 

 increased light supply. 



Just as the pine should be admixed to other species only in 



