251 



The Forestry Commission of New South Wales has issued, August, 1918 (the researches 

 were made in 1916), Bulletin No. 13, under the above title, compiled from data supplied 

 by W. A. W. de Beuzeville, Forest Assessor, of which a brief abstract is sufficient for 

 the present purpose. 



The determination of the rate of growth of trees and forests is of fundamental importance to the 

 forester, because, without accurate knowledge of this subject, he is unable to fix the annual yield of the 

 forest at that quantity which will ensure that the forest be not over-cut and the forest capital exhausted. 

 The large number of forests throughout the State, which have been operated upon to such an extent that 

 supplies of milling timber are now no longer available, is sufficient evidence of the disastrous result of 

 over-cutting, and the necessity of ascertaining rates of growth and regulating the annual cut accordingly. 



Rate of growth may be ascertained either by systematic measurement of standing trees in all stages 

 of growth over a considerable number of years, or by making what is known as stem analyses of felled trees. 

 Stem analysis can be applied only to those species the timber of which shows well-defined annual rings 

 of grow T th, and for this reason, unfortunately, is inapplicable to the great majority of Australian species. 

 Where possible, however, the method should be used, as it enables the forester to obtain valuable data 

 upon which to regulate cutting operations while waiting for the more accurate information secured from 

 the direct measurement of growing trees. 



It should be remembered, however, that the rates of growth ascertained by stem analysis of trees 

 in virgin forests do not necessarily represent the rates which will be obtatined in the future under careful 

 forest management. The forest trees from which the selection must be made have attained to maturity 

 only after a long struggle against the competition of their rivals, and without the aid of the forester, who 

 by well-regulated thinnings, can do much to accelerate the rate of growth. Consequently the figures 

 obtained from stem analysis should be regarded rather as the safe minimum to be expected in the future. 



For the purpose of obtaining authentic information relative to the growth of 

 species of Eucalyptus on the southern tableland, Mr. Forest Assessor W. A. W. de 

 Beuzeville made stem analysis of the Buddong Mountain Ash (E. gigantea Hook). 



The figures and conclusions arrived at for the Mountain Ash are given in full 

 in the Bulletin, as it is reported to be the fastest growing species in New South Wales. 



The specimen selected for investigation was a typical forest tree, well grown and carrying a heavy 

 crown occupying little more than half the total height of the tree. It was felled at ground level, and the 

 main stem marked off into nme pieces, each of which was cut through the centre. The concentric rings 

 on each section were counted, and the diameters measured, the information being then tabulated, and 

 the calculations made on the assumption that the concentric rings were annual.* (The method followed 

 is that described in Chapter VI of vol. iii of Schlich's" Manual of Forestry," to which readers are referred.) 



Details of the Analysis- 

 Section 1 taken at the foot of the tree showed 97 rings. 



2 



33 



5 feet above 



ground level 



33 



97 



3 



„ 



15 „ 



3) 



33 



95 



4 



33 



25 „ 



33 



,, 



93 



5 



33 



35 „ 



33 



33 



91 



6 



33 



45 „ 



33 



33 



88 



7 



J) 



55 „ 



33 



33 



85 



8 



3) 



65 „ 



35 



33 



79 



9 



3) 



105 „ 



33 



33 



53 



Top, 35 feet long; total height, 140 feet; age, 97 years. 



* If the rings are seasonal instead of annual, and it may be that two rings per year are formed, it will be seen 

 that the growth of the tree3 was extraordinarily fast. This will not, however, affect the underlying principle whiclj 

 this bulletin is intended -, ■-* 'x plain. 



