Soone Coinmom Hardivoods. 



895 



In dealing with tlie forest, by taking the average of as many 

 typical trees as possible, we naturally eliminate individual 

 variations vei-y largely. Nature varies widely, but it varies around 

 a mean, and it is the mean I have attempted to get. 



Since the publication of my paper on diameter growth, a further 

 series of measurements have been taken, and the resulting curve is 

 very little different from the former one. I have attempted to 

 carry the measurements to 100 years, but the results have not been 

 satisfactory. The distinction between autumn and spring wood 

 is not at all clear. With our long growdng season and favourable 

 weather it is not surprising that the limits of the rings are ill 

 defined. 



Bcr 



90 



50 60 JO 



Years of Growth 

 Fig. I. 



The figures on which the curve for Mountain Ash (Eucalyptus 

 regnans) is based were obtained in the Warburton area, while those 

 for Blackwood (Acacia melanoxylon) were obtained at Beech Forest. 

 Mountain Ash appears to groAv slightly slower in Beech Forest, but 

 the studies were not completed. The other curves are inserted for 

 comparison. The figures for these curves were obtained as follow : 

 — Cluster Pine, State Forest, Leiria, Portugal, quoted in a paper 

 at British Association, 1014, by E. D. Hutchins, and published in 

 "Australian Forestry." Spruce, from "Farm Woodlot," by 

 Cheney. 



On comparing the graphs it will le noted that the curves for 

 Mountain Ash and Blackwood differ widolv from the others. 



