Periodical Literature 533 



historically interesting in showing the ups and downs of the beech 

 wood market, we quote only the last sentences, showing that the 

 value increment of clear boles rises more rapidly and continuously 

 than that of branchy wood absolutely and relatively to the value 

 of the stand. However the rotation is determined, the felling age 

 for clear timber arrives later than for branchy timber, calling 

 therefore for a proper care of stands. 



The following discussion for pine and spruce is also based on 

 Bavarian data for 1912. The assortment is made on the basis of 

 top diameters at any height varying by 2 meters, when the time 

 involved is that required for making the length (as determined by 

 yield tables) and diameter (as found in each case by ring countings) . 



For spruce the tabulation is made for II site on the basis of an 

 average diameter increment of the mean sample tree of ^/s cm 

 (6 to 7 years per inch) and the annual value increments are for : 



Age 63-77 77-90 90-107 107-127 



Per cent 1.5 1.2 .5 .2 



This shows that even on good sites the production of the stoutest 

 class cannot be the aim of management. Even the II class can only 

 in a limited way be considered as one financially to be worked for. 

 The rotation based on value production under the economic condi- 

 tions where the data were gathered will on best soils be placed 

 aroimd 90 years, on middle class sites around 80, and on poor soils 

 aroimd 70 years. 



Similar results follow from Saxon data : 



Age 60-80 80-100 100-120 120-140 



Value Increment, Per cent 1.2 1 .6 .2 



The increment of 1 per cent up to the 100th year brings the index 

 per cent up and defers the felling age somewhat, but the value 

 increment then falls so rapidly that this delay can only be short, 

 especially as the volume increment also declines. All considera- 

 tions in Saxony have led to an 85-year rotation for spruce in general. 

 A similar calculation for pine is made upon the basis of Wimme- 

 nauer's tables based on a thinning practice which gives a constant 

 basal area of 130 square feet to the acre (30 qm per ha.), when the 

 average annual diameter increment from 60 to 140 years approxi- 

 mates Vs <^w (6 to 7 years per inch). The result is as follows: 



Age 55-70 70-85 85-103 103-123 



Value Increment, Per cent 1.7 1.7 1.1 1.3 



