SITK DKTl'RM I NATION' ANO VlKLU r(JKi:CAST 7 



indicating "Site II." Under Professor Roth's plan of classification 

 this would probably be taken care of in some such way as "Standard c, 

 Site IV," for chestnut oak, and "Standard b, Site II," for white pine. 

 Rather than introduce a possible clement of confusion at this stage 

 in the game, however, it was considered best to cast out white (and 

 other species of) pine as hardwood site indicators, leaving the deter- 

 mination of sites in terms of pine for a later date. Another somewhat 

 similar case involved shortleuf pine and hardwoods. In another case 

 very old chestnut exhibited a height considerably in excess of what 

 could be expected from young trees in the vicinity. The slow growth 

 of the young timber was here attributed to deterioration of the site 

 (which had been repeatedly burned over), rather than to the remote 

 possibility of the older trees having been favored by pockets of deep 

 soil. 



Another plot, at the top of Looking Glass Rock on the Pisgah 

 National Forest, showed a mature height of 45 feet, while 22 year-old 

 second growth sprouts and seedlings had already reached heights of 

 from 31 to 38 feet. A possible explanation of this rapid early growth 

 (approximating that in the coves) lies in the amount of soil, which, 

 though limited, was sufficient to supply moisture for rapid early 

 growth up to a certain point, and in the protection from wind afforded 

 by the crowns of old-growth trees near by. 



In considering the method of applying the site classification it was 

 felt that the retention of the uneven spacing between the curves was 

 unnecessary, since the determination would usually be based upon 

 averaged heights for one or more ages, and not likely upon a range 

 of heights of any such width as that shown by the curves. The spacing 

 was therefore evened, and the sites were increased from three to six 

 by evenly-spaced interior curves. To conform to an excellent sugges- 

 tion of Professor Roth that an even unit of 10 feet, or a multiple, at 

 100 years be adopted as a standard interval in all age-height site classi- 

 fication, these curves were drawn through points 20 feet apart at 100 

 years, the lowest being 30 and the highest 150 feet. The sites thus 

 indicated were designated la, lb. Ila. lib, Illa, and Illb. so that they 

 may be used for either a three or a six class differentiation, depending 

 upon the degree of refinement required. The curves are shown in the 

 accompanying diagram together with part of the individual dominant 

 tree basis sui)porting the upper and lower curves. The average height 

 growth of yellow poplar, chestnut, and oak, read from tables made in 

 previous studies, is also shown by symbols. It should be noted that 



