550 Forestry Quarterly 



Altogether, the severe thinning produces in pine, increased 

 height, longer clear bole, improvement of form, increased vol- 

 ume and value increment. The author then cites Wimmenauer's 

 yield tables of pine {see F. Q., VI, p. 432), which show that 

 severely thinned and underplanted pine stands on I to III site are 

 best managed so that the basal area per acre does not exceed 

 130 square feet, or is reduced to that amount at each thinning : 

 under such management the annual ring for many decades can 

 be kept at an approximately uniform width. Wimmenauer also 

 succeeded in securing a somewhat larger total wood production 

 than with full crown cover according to Schwappach. Usener's 

 increment per cents {see F. O., V, p. 430) figured for pine in 

 Alsace, are cited, showing again that under the influence of 

 severe thinnings the volume per cent begins to sink, and that only 

 slowly, at around 100 years, when it had reached 1.4 per cent. 

 The quality per cent is then still rising till 120 years, when it 

 had reached .9 per cent, and a price increment culminates the 

 same year, so that the entire value increment in that year reached 

 3.9 per cent, sinking slowly thereafter. This indicates a rotation 

 of 100 to 120 years. Such a rotation is also indicated by the 

 size requirements in the market, and by the valuable heartwood 

 formation, which under lower rotations remains insufificient. 



The performance of three areas near Eberswalde during 16 

 years is cited, which also were severely thinned, opened up and 

 under-planted, one area opened up to 68 per cent, one to 73 per 

 cent of the basal area, the third experiencing a mere severe thin- 

 ning. All three areas in 16 years show practically the same area 

 increment, namely about 40 to 43 square feet, or 2.5 to 2.7 square 

 feet per annum, in spite of the removal of 1,530, 2,730, and 3,160 

 cubic feet on the respective areas. A maximum product, the 

 author suggests, might be looked for by applying an opening 

 between the severe thinning and 73 per cent opening. It is also 

 noteworthy that the diameter increase in the severe thinning was 

 6.7 cm during the 16 years, in the openings 8 cm or almost 20 per 

 cent more. 



Lastly the increment figures for a 120-year-old mixed stand 

 near Eberswalde of pine and beech, not treated, are given to 

 show the superiority in production of the latter over similar 

 pure stands of the same age, more or less severely thinned. We 

 give the tabulation in the original measure per hectare. 



