THE EASTERN HEMLOCK. 



25 



Local variations in growth are also caused by climate and the 

 quality, depth, drainage, and moisture of the soil. Growth is most 

 rapid on the best soils. Hemlock is especially favored by a temper- 

 ate, humid climate and long, growing season, combined with moist 

 but well-drained soils — conditions which it finds in the coves and 

 slopes of the southern Appalachians. 



Tables 8 to 1 1 show the growth of hemlock in localities in various 

 parts of its range. The tables give the maximum, minimum, and 

 average rates of growth in height, diameter, and volume, and are 

 based on measurements of many forest-grown trees differing widely 

 in amount of suppression. Though not based on crown-class dis- 

 tinctions, the maximum figures may safely be regarded as represent- 

 ing the average growth of dominant trees on good soil, and the mini- 

 mum that of suppressed trees which have reached merchantable 

 size. The average figures, however, may represent the growth both 

 of trees" of the middle crown classes and of dominant trees in situa- 

 tions of poor quality. These data were averaged separately for 

 diameters, heights, and volumes, so that only an approximate 

 relation exists between the values for any given age. Furthermore, 

 the variation in height and volume among trees of a given diameter 

 is considerable, as shown by the volume tables in the Appendix. 



Table 8. — Growth of hemlock in Leelanau County, Mich. 



Age. 



Diameter, breast-high. 



Height. 



Volume. 



Inches. 



Feet. 



Cubic feet. 



Board feet. 



Mini- 

 mum. 



Aver- 

 age. 



Maxi- 

 mum. 



Mini- 

 mum. 



Aver- 

 age. 



Maxi- 

 mum. 



Mini- 

 mum. 



Aver- 

 age. 



Maxi- 

 mum. 



Aver- 

 age. 



Maxi- 

 mum. 



Years. 

 20 

 30 

 40 

 50 



60 

 70 

 80 

 90 

 100 



110 

 120 

 130 

 140 

 150 



160 

 170 

 180 

 190 

 200 



0.3 

 .6 

 .9 



1.3 



1.6 

 2.0 

 2.4 

 2.7 

 3.1 



3.4 

 3.8 

 4.3 

 4.8 

 5.3 



5.9 

 6.6 

 7.3 

 8.0 



8.7 



0.7 

 1.3 

 2.1 

 2.9 



3.8 



4.7 

 5.7 

 6.7 

 7.8 



9.0 

 10.0 

 11.2 

 12.3 

 13.4 



14.5 

 15.5 

 16.5 

 17.5 

 18.4 



2.0 

 3.9 

 5.7 

 7.6 



9.4 

 11.1 

 12.8 

 14.5 

 16.1 



17.7 

 19.4 

 21.0 

 22.6 

 24.2 



25.7 

 27.2 



6 

 7 

 8 

 10 



11 

 13 

 14 

 15 

 17 



18 

 20 

 21 

 23 

 25 



27 

 29 

 31 

 33 

 35 



8 

 12 

 16 

 20 



25 

 30 

 35 



40 

 44 



49 

 53 

 57 

 60 

 63 



66 

 68 

 70 

 72 

 74 



18 

 31 

 42 

 53 



62 

 70 

 76 



82 

 85 



88 

 91 

 94 

 96 



98 



100 

 102 



























2.2 



6.6 



12.4 



20.0 

 29.0 

 39.0 

 50.0 



64.0 

 78.0 

 94.0 

 112.0 

 131.0 



152.0 

 174.0 











7 



20 

 35 

 50 

 67 

 86 



110 

 130 

 150 

 180 

 210 



13 



31 

 56 

 80 

 130 

 180 



240 

 320 

 410 

 500 

 600 



700 



810 



910 



1,020 



1,130 











1.0 



1.8 

 2.6 

 3.4 

 4.6 

 5.9 



1.8 

 3.6 

 5.9 



9.2 

 12.5 

 17.1 

 22.0 

 28.0 



34.0 



40.0 

 47.0 

 54.0 

 61.0 



1 Based on measurements of 186 trees, 109 to 325 years old, made by S. J. Record in 1905. 



