504 Forestry Quarterly. 



In the White Alountains, on the other hand, the hardwood type 

 occupies 55% of the total area and the average stand under vir- 

 gin conditions is 15,000 bd. ft. Forty percent of the total area 

 is in the spruce type and the average stand in virgin conditions 

 is 15,000 bd, ft. The remaining 5% of the area is in the sub- 

 alpine and barren types and contains no merchantable timber. 

 Using these figures, an average stand for virgin conditions in 

 the White Mountain region is figured to be 14,250 bd. ft., over 

 three times the average stand in the Appalachians. 



On first thought, nearly every one would be inclined to as- 

 sume that more timber could be produced in a given period in 

 the Southern Appalachians than in the White Alountains. In 

 the latter region the precipitation is less and the growing season 

 is much shorter. These two reasons would seem to indicate that 

 the Southern Appalachians are more favorably located climat- 

 ically for rapid tree growth. 



In order to determine just what the climatic differences are, 

 a number of diagrams are given which show graphically the pre- 

 cipitation, average temperature, and length of growing season 

 for a number of representative Weather Bureau stations in each 

 region. From these diagrams it is evident that the precipitation 

 is 24% greater on the average in the Southern Appalachians, 

 I'thie temperature 28% higher, and the growing season 41% 

 longer. While exact figures for the amount of cloudiness are 

 not available it is estimated that there is about 25% more sun- 

 shine in the Southern Appalachians. 



In order to find out the effect of the climate upon tree growth 

 a comparison of the amount of volume which could be produced 

 in a period of 50 years has been made. In the White Moun- 

 tain region figures are only available for white pine and red 

 spruce while in the southeast the data are restricted to figures 

 for loblolly pine, scrub pine and yellow poplar. Diagrams are 

 given which show for each individual species the number of cubic 

 feet produced per acre in 50 years. Averaging the figures for 

 the different regions it is evident that 34% more volume is pro- 

 duced in the northeast than in the southeast. 



Since the main factors of volume are diameter, height and 

 number of trees, it is necessary to compare these different fac- 

 tors in order to determine what causes the difference in volume 

 in the two regions. In order to bring out the differences clearly, 



