58 



SEEDING AND PLANTING 



trees are in excellent form and only about 10 per cent of them 

 have become suppressed. The stand now measures approximately 

 30,000 board feet per acre and is superior to unthinned stands of 

 the same age planted at closer intervals. 



FIG. 13. An unthinned white pine plantation 44 years old and spaced 

 8 by 8 feet. Near Keene, New Hampshire. 



8. Spacing in Forest Plantations in the United States 



Although much depends upon the species and the site, we are 

 seldom justified in the United States in a closer spacing than 

 4 by 4 feet. Only with oak and other hardwoods that develop 

 heavy side branches is as close spacing as this warranted. As a 

 rule, when early thinnings cannot be made each tree should be 

 given a growing space of from 36 to 64 square feet. A spacing of 

 6 by 6 feet is the most acceptable for most species and under most 

 conditions. When large stock is used, when the species are of 

 very rapid height growth, or when the stand is grown under a short 

 rotation, a wider spacing is often justifiable. In most of the plant- 

 ing on the National Forests the spacing is from 6 to 9 feet in each 

 direction. The contention is that where thinnings cannot be made 

 even a wider spacing will give as much timber at the end of the 

 rotation as would result from closer spacing unaided by early 

 thinnings. 



