REVIEWS 



Grozvth Studies and Normal Yield Tables for Second Growth Hard- 

 wood Stands in Nciv England. By J. Nelson Spaeth. Harvard Forest, 

 Bulletin No. 2, pp. 21, figs. 2. Harvard University Press, 1920. 



This is a most welcome addition to our knowledge of growth and 

 yield. It is particularly valuable since it deals with second growth 

 hardwood stands which, as the bulletin states, "have thus far received 

 but little attention." The bulletin is based on the actual volumes of 

 fully-stocked, natural stands in North-Central Massachusetts. The 

 yields are the minimum to be expected under forest management. 



Forty-eight sample plots were measured — all in fully-stocked stands 

 of even age. The plots were chain-wide strips and either one-half or 

 one-quarter acre in size. Trees were calipered down to two inches. 

 Heights were taken by crown classes. In age. the plots ranged from 

 17 to 75 years. 



Forty of the plots are in "better second growth hardwoods," further 

 divided into sites I and II on the basis of average height of dominant 

 trees. The remaining plots are in "inferior second growth hardwoods." 

 In the former, red oak constitutes from 20 to 27 per cent of the trees, 

 white ash 14 to 15 per cent, red maple 12 to 15 per cent, and yellow 

 birch 8 to 10 per cent. 



In the inferior hardwoods, gray birch is 38 per cent of the stand, 

 red maple is 24 per cent, and poplar 15 per cent. By careful selection 

 of plots error due to the presence of chestnut was reduced to a small 

 percentage. 



Under the heading "Increment" the bulletin says "Properly included 

 in yield tables, but easily derivable from data given, increments are 

 omitted in order that the tables may not prove cumbersome." This 

 was an error in judgment. As Bentley points out ("Forest Manage- 

 ment," Wiley & Sons, N. Y., 1919, Art. 71), "the chief uses of yield 

 tables are . . . (3) to make comparisons between the actual cur- 

 rent annual increment or mean annual increment of a given stand and 

 the normal increments as shown in the table." Another advantage is in 

 determining the economic rotation (that of maximum average volume 

 production) which coincides with the culmination of the mean annual 



421 



