A GENIvRALlZF.l) VHJJJ TAIiLK 387 



Still fall in the same general site class in volume as in site based 

 upon heij^lit. A yield table on this basis, however, would not be as 

 representative uf actual conditions. 



After the generalized cubic volume curves had been drawn the 

 selected plots, separately for each type, were plotterl with reference to 

 these curves. It was found that the plots for the '"chestnut over 50 

 per cent'' had the widest range in yields — from site III to Vll. "Chest- 

 nut under 50 per cent" plots range from III up to V. The chestnut 

 oak plots range from site II up to V, which is the lowest range of any 

 of the oak or chestnut types. White oak ranges from III to V, red 

 oak IV to V, black oak III to VI, and scarlet oak III to V. Yellow 

 poplar, including plots by Ashe, range from IV to VII in volume. The 

 one black cherry plot taken is in site VI. while one ]>lot each of pitch 

 pine and l)eech are in site II. 



The board-foot volume curves indicate at 50 }ears a range in yield 

 of 400 board feet per acre for site III, with none for site II, up to 

 24,000 feet for site VII, while at 100 years the range is from 1.250 

 board feet for site II up to 40,000 feet for site VII. 



While there is no great difference due to type in total cubic yield for 

 a given standard site, yet what is of more practical importance is how 

 the different types vary from the generalized yield table in possible 

 board foot yields. This was shown by plotting the selected plots, 

 separately for each type, with reference to generalized board foot 

 volume curves, and labelling the site class of each point plotted accord- 

 ing to its height and cubic volume. It was surprising to find how little 

 the different types vary in their board foot volume, for plots of a 

 given site according to height and cubic volume, from the generalized 

 board foot volume site classes. The chestnut oak plots varied the most, 

 a large number of which fell in a lower site class in board foot than in 

 cubic volume. This was to be expected from its thicker bark. The 

 "chestnut over 50 per cent" plots, on the other hand, tended to show 

 greater yields in board feet, for plots of a given site according to 

 height and cubic volume, than the generalized board foot volumes for 

 that site would indicate ; and the one pitch pine plot showed very much 

 greater board foot volume, being in site IV instead of site VI as in 

 height and cubic volume. 



It is of practical importance to see how the generaJized table fits 

 conditions farther north and west. This w^as done for 233 plots taken 

 by Frothingham, and 30 plots taken by Schwartz in Connecticut. These 



