GEOWTH. 



47 



GROWTH. 



The growth of the jack pines planted in the Nebraska sand hills 

 has been just about the same as that of the Bruner plantation, de- 

 scribed in Table 6, though the planting of 1903, with forest seedlings 

 about 3 years old at the time of planting, is the only one old enough 

 to be comparable. At the end of 1910 — that is, after eight years 

 in the hills — these jack pines had an average height of 7.54 feet and 

 a maximum height of 10 feet. The trees have not been stimulated 

 to height growth by crowding, as in the Bruner plantation, where 

 they were spaced 2 by 2 feet, but since 1910 they have been making 

 at least a foot a year in spite of insect damage. These facts indicate 

 that the tree will, at least for a number of years, make good develop- 

 ment. It can hardly be expected that jack pine will attain in the 

 light soil of the sand hills more than its average height, about 60 feet. 



From the planting of 1909, when, for the first time, the several 

 species were planted side by side at Halsey, with stock of the same 

 age (2-1 transplants) it is seen that jack pine makes better height 

 growth in the early stages than any of the other species. This 

 earlier supremacy may not be maintained. It already appears that 

 yellow pine is capable of fully as rapid growth when once established, 

 and the tree normally attains a much greater height. The com- 

 parative growth of the several species is shown by Table 13. 



Table 13. — Comparative growth of different species of pine in the Nebraska sandhills. 



Site. 



Species. 



Growth, 

 1911. 



Total 



height, 



end of 



1911. 



Proportion 



of total 

 height at- 

 tained at 



sixth year. 



South slope. 



Do 



Do 



Do 



Do 



Bottom 



North slope. 



Do 



Do 



Ridge 



Do 



Jack pine 



Yellow pine... 

 Scotch pine... 

 Norway pine.. 

 Austrian pine ' 

 Yellow pine... 



do 



Scotch pine . . . 

 Yellow pine... 



do 



Austrian pine ' 



Inches. 



3.4 

 2.1 



1.8 

 1.6 



Inches. 

 18.1 

 6.3 

 9.0 

 7.8 

 6.4 

 6.4 

 7.6 

 12.0 

 7.1 

 6.6 



Per cent. 



I Austrian pine trees were 2-year seedlings 

 the otner species. 



time of planting, hence are 1 year younger than trees 



of 



Yellow pine is barely getting under way at six years, while jack 

 pine is growing much more vigorously. Table 14 gives figures for 

 older plantations of yellow pine and those for some of slightly greater 

 age than in the Halsey plantations, grown naturally in the Pine 

 Ridge region.^ 



2 From '< Forest Belts of Western Kansas and Nebraska," Bulletin 

 Agriculture. 



5, Forest Service, U. S. Dept. 



