U S DEPT. OF AGRICULTURE 

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RESEARCH NOTE LS-17 



_AKE STATES FOREST EXPERIMENT STATION, — tfc-Sr-D-E-PARTM ENT-OF AGRIC ULTURE 



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^Influence of Regular Spacing on Growth 

 of a Red Pine Plantation^ 



The uniform spacing in plantations is 

 known to influence their early growth and 

 development. Only a few of the older plan- 

 tations, however, have developed without 

 hardwood overstories or have a continuity of 

 records that show their growth characteris- 

 tics and yield potentials. The record of an 

 unmanaged 51-year-old red pine plantation in 

 Crawford County, Mich., indicates that reg- 

 ular spacing results in growth characteristics 

 markedly different from those of natural 

 stands (fig. 1). 



The study plantation was established by 

 the Michigan Department of Conservation in 

 the fall of 1912, using a 2-0 stock of local 

 origin. The initial spacing, averaging 4V2x5 

 feet, was closer to the generally dense spacing 

 of natural stands than that of later plantings. 

 The planting site was a level field of Grayling 



sand soil that had been farmed and aban- 

 doned a few years earlier. The site quality is 

 medium for red pine, with the average domi- 

 nant and codominant tree about 51 feet in 

 height at 51 years of age. Survival, averaging 

 84 percent, was higher than in many of the 

 early plantings, since there was no invasion 

 by hardwoods. 



Periodic measurements on a half-acre plot 

 were begun in 1934 when the plantation was 

 24 vears of age from seed. Remeasurements 

 were made in 1939, 1949, 1956, and 1961. To 

 illustrate the differences in growth character- 

 istics, the plantation data at each remeasure- 

 ment age are compared with those of natural 

 stands 1 on similar sites (table 1). 



Eyre, F. H., and Zehngraff, P. Red pine manage- 

 ment in Minnesota. U. S. Dept. Agr. Cir. 778, 

 70 pp., illus. 1948. 



Table 1. — Stand characteristics at different ages for an unmanaged red pine plantation and yield table 



lvalues for natural stands, site index 50 





















Cordwood 



Total 



age 



( years ) 



Trees 



oer acre 1 



Basal area 



per acre' 1 



Av. 



d.b.h: 



Cubic vol. 



per acre 2 



vol. per acre 2 



Plan- 

 tation 



Natural 

 stand 



Plan- 

 tation 



Natural 

 stand 



Plan- 

 tation 



Natural 

 stand 



Plantation 



Natural 

 stand 



_,, ... Natural 

 Plantation stand 





Number 



Number 



Sq. ft. 



Sq. ft. 



Inches 



Inches 



Cu. ft. 



Cu. ft. 



Cords Cords 



24 



1,568 



2,100 



88 



93 



3.2 



3.1 



17 



275 



0.2 3.2 



29 



1,568 



1,262 



134 



105 



4.0 



4.0 



316 



594 



4.0 7.9 



39 



1,518 



732 



199 



123 



4.9 



5.7 



1,605 



1,327 



21.0 18.7 



46 



1,468 



569 



224 



134 



5.3 



6.6 



2,630 



1,875 



33.7 26.6 



51 



1,404 



510 



236 



140 



5.5 



7.2 



3,371 



2,235 



41.9 31.5 



1 Trees 0.6 inch and larger. 



2 Trees 4.6 inches and larger to a 4.0-inch top diameter inside bark. 



MAINTAINED AT ST. PAUL 1, MINNESOTA, IN COOPERATION WITH THE UNIVERSITY OF MINNESOTA 



