FOREST PLANTING AND SEEDING 



75 



The following table gives the number of trees required to 

 stock one acre when set at different distances apart. 



Distance of spacing Number of trees per acre 



3 by 3 feet 4840 



4 by 4 feet 2723 



5 by 5 feet I742 



6 by 6 feet 1210 



7 by 7 feet 889 



The general principles underlying spacing may be stated here 

 and the planter may judge for himself what distance best meets 

 his own requirements. Close planting forces the trees up in 

 order to secure light, and thus produces a rapid height growth. 

 At the same time it kills the lower limbs for lack of light, thus 



Fig. 24. A block of 3-year-old white pine transplants; the best stock with which to 

 start a commercial plantation. 



causing natural pruning. The result is a long, slender log fairly 

 free from knots. Open planting, on the other hand, produces a 

 large-branch system, a rapid diameter growth, especially near 

 the base, and a rather slow height growth. The result is a short, 

 thick log tapering rapidly from base to top and rather knotty. 

 For the production of high-grade lumber the former is evidently 

 to be advised; for a heavy production of fuel wood, pulp wood, 

 railroad ties, or other inferior materials, the open spacing may 



