378 Forestry Quarterly. 



the report of the Commission. Since the number of copies of this 

 report published is so limited as to prevent its distribution among 

 forest students, I hope very much that the following discussion 

 by Mr. Ziegler upon present growth can be given publicity in the 

 Quarterly. 



I am sure any further discussion of this paper as well as of 

 others issued from the Service will be welcomed by the readers 

 of the Quarterly.* It is only in this way that the truth can be 

 finally established, and the absence in so many cases of sufficient 

 data upon forest growth, conditions and stand gives room for 

 wide divergence of opinion. 



R. S. Keiaog. 



After giving all the available data upon the growth of individual 

 species in various localities Mr. Ziegler continues his article as 

 follows : 



Present Average Production Per Acre and Total Pro- 

 duction. 



From the foregoing notes on the growth of the different species 

 and the yield per acre in the infrequent fully stocked stands of 

 second growth forest, little information can be got on the actual 

 wood production throughout our forests, since growth conditions 

 are often very unfavorable. In the very old mature forests growth 

 is offset by decay, and our millions of acres of this type of forest 

 may for all practical purposes be regarded as nonproducing capi- 

 tal. Were all our forests of this class, the production per acre 

 would be zero. Were all mature trees removed and the land all 

 densely stocked with thrifty growth, the yield would approximate 

 from 30 to 1 10 cubic feet per acre per year according to the species 

 and locality. The actual forest represents all degrees of produc- 

 tion between these two extremes. There are large bodies of over- 

 mature timber that are not increasing. There are small areas of 

 pure second growth producing the maximum amount. There 

 are culled-over areas containing mature defective trees or unde- 

 sirable species mixed with second growth, areas denuded by ax 



* The reviewer is glad to have provoked the above most interesting 

 article, which really was the object of his criticisms. Ingenious as the 

 method of arriving at data upon which to make a statement of the acre 

 production, the result does not fill the reviewer with any more confidence in 

 its truth than his own mere guesses. 



