THE PRINCIPLES WHICH DETERMINE SPACING 59 



If the spacing does not exceed 10 by 10 feet, the stand will 

 usually produce as much timber at maturity as a closely spaced 

 unthinned stand. Close spacing causes the trees to clear more 

 satisfactorily and permits the selection of the straightest and 

 best for the final stand, as the poorer trees are taken out in the 

 thinnings. Consequently the timber is of better quality. 



In nearly all of the plantations made in New England and in 

 the Central and Lake States in recent years the spacing has been 

 approximately 6 by 6 feet. As a rule, plantations set at closer 

 intervals have suffered from stagnation or overcrowding due to the 

 lack of early thinnings. Wider spacing has seldom been practiced 

 in eastern United States but is chiefly confined to the western for- 

 ests where because of economic restrictions early thinnings cannot 

 be made and where vast areas await artificial regeneration. 



9. Spacing in European Practice 



In European practice the closeness of spacing has been largely 

 governed by the possibility of profitably utilizing early thinnings. 

 Although much difference of opinion exists, until recent years 

 there has been a marked tendency toward close spacing. The 

 contention was made that wide spacing with the consequent 

 delayed closing of the crown cover encouraged the growth of 

 weeds and grass and caused a general impoverishment of the soil. 

 It was generally believed that the yield per unit of area was 

 greatest with close spacing. Thus many plantations were set with 

 from 4800 to 7200 plants per acre or at intervals of from 2| to 

 3| feet. A spacing wider than 4 feet was seldom practiced except 

 in the more inaccessible regions. In recent years the tendency 

 throughout Europe has been toward much wider spacing. Thus 

 in Saxony, which is a land of spruce experts, the spacing of spruce 

 now calls for from 1800 to 2400 plants per acre. A long series of 

 carefully conducted experiments with spruce at the Austrian forest 

 experiment station at Mariabrunn, Austria, appears to show that 

 under average conditions a spacing of 4.9 feet each way gives the 

 best results with this species. 



Nearly all recent investigations demonstrate that the expense 

 involved in the greater cost of close planting, in the necessity 

 for early thinnings, and in the decreased growth in the crop 

 trees is not justified. It appears that a wider spacing gives a 

 greater profit in the long run and that the resistance of the stand 



