30 



THE COMMERCIAL HICKORIES. 



The rapid growth shown in eastern Maryland and Pennsylvania is 

 due to extremely favorable conditions. The trees measured were 

 growing on agricultural soils of excellent quality, deep reddish sandy 

 loams underlain by gneiss, and the stands had been opened up and 

 growth stimulated. The trees measured in the Mississippi Valley 

 and Cumberland Mountains also were growing on good soils, the 

 former on rich alluvial soils of river bottoms, and the latter generally 

 on rich north and east slopes. Their slow growth is due to their 

 development in the virgin forest, though their extreme persistency 

 indicates that under management their growth in either region would 

 be as fast as if not faster than in eastern Maryland. In the Ohio 

 Valley the trees were growing on low hills which characterize southern 

 Indiana and northern Kentucky, on less favorable soils, mainly red 

 clay, with the underlying rock, sandstone, limestone, or slate. The 

 trees, however, were strictly second growth. In northern Ohio the 

 land is flat and is underlain by a stiff, almost impermeable clay, 

 which keeps the top soil wet most of the year. The trees measured 

 were strictly second growth. 



Pignut, shagbark, and big shellbark hickories show similar rates of 

 growth, and all three are very persistent. Mockernut and bitternut 

 grow more rapidly at first, but the rate soon decreases and the trees 

 seldom reach large size. 



Table 4, made up from measurements of second-growth trees in 

 southern Indiana and northern Kentucky, shows approximately what 

 may be expected from hickory grown under forest management. 



TABLE 4. Diameter growth of normal second-growth hickory. 



The pignut was growing on only moderately good soil, the shag- 

 bark on soil of somewhat better quality, and the bitternut on very 

 good soil. Under similar soil and light conditions there would proba- 

 bly be little, if any, difference between pignut and shagbark. Bitter- 

 nut, however, is not only a faster-growing tree, but grows characteris- 

 tically on the richer soils. 



