253 



Then we come to a paper : " Determination of the Increment of Trees by Stem 



Analysis. No. 1. Eucalyptus viminalis," by W. A. W. de Beuzeville, Journ. Roy. 



Soc. N.S.W., liii, 239 (1919). (N.B.— The species is really E. Dalrympleana Maiden, 



as described by me in " Forest Flora of New South Wales," Part LXIV, p. 137. It was 



formerly confused with E. viminalis.) 



The calculations show that the tree increases in height rapidly until about thirty years old, averaging 

 2*8 feet per annum. This rate gradually diminishes, dropping to 1-6 feet mean annual increase when 

 sixty-sis years old. The diameter increase, likemse, is greater during youth, but is fairly evenly main- 

 tained during the whole period, ranging from -37 inches to 3 inches per annum. The mean annual volume 

 increment, which was -1 cubic feet at ten years, showing a steady improvement, reaching 1-13 cubic feet 

 at sixty-six years of age. 



EarHer in point of pubhcatiou than the preceding papers, w^e have " Timber 

 Production and Clrowth Curves in the Mountain Ash {Eucalyptus regnans):' by E. T; 

 Patton, Proc. Roy. Soc. Vict., xxx (N.S.), i (1917). 



It is not convenient to reproduce the graphs of the papers of either Mr. Patton 

 or ^Ir. de Beuze^alle. AH the papers should be carefully read, and I will content myself 

 with a few extracts of Mr. Patton's paper also. 



It has been said that Mountain Ash will mature in forty years, and will give in this time a butt of 

 from 2 feet to 2 feet 6 inches. It has also been claimed for Mountain Ash that it is the fastest-growing 

 tree in the world, and that it will give a cut of 150,000 feet super, per acre. In order to tc'^t the truth of _ 

 these statements a series of measurements was carried out at Powelltown on logs of this timber. 



It was found impossible at the time to get any reliable figures as to either its fast growing rate or 

 its quantity of timber per acre. Many factors militated against this. In the first place, aU the forest 

 now being cut is over ripe, and consequently many trees are hoUow. Again, a very large number of trees 

 have incipient decay in the heart. Other factors also prevented any accurate estimate being formed. 

 However, there was ample material for a study of the annual rings. It was impossible to obtain 

 measurements from all logs coming in, as in quite a percentage there was either a pipe, or decay had 

 proceeded far enough to destroy the boundaries of the first annual rings. Only those logs then were 

 taken in on which the annual rings were clearly defined. The measurements were taken to the eightieth ring, 

 and not continued further owing to the difficulty in many cases of distinguishing the rings. In one case 

 the rings, though narrow, were easily distinguishable to the 12.5th ring. It was obvious from these later 

 rings that the tree had lacked vigour. This was borne out by a study of the trees in the standing forest. 

 The paucity of foliage on these big trees is very noticeable, as was also the amount of mistletoe. No mistletoe 

 was observed on the saplings, or even on trees half grown. From these observations one was led to conclude 

 that the tree reaches its prime well under a hundred years. 



The most remarkable feature is the rapid expansion of the trunk (and hence width of annual ring), 

 during the first ten years of growth. . , . 



The differences between the width of the annual rings as the tree gets older will be loss and less. 

 There is a point of interest here, and that is that the enormous decrease in the width of the ring may be 

 due to overcrowding, or putting it in other words, that, as the trees grow older, and so many are striving for 

 the same light and carbon dioxide, the crown is npt as large as it would be if the forest were controlled. 

 It was very apparent from a study of the mature trees that width of ring is largely dependent on the distance 

 of the trees apart, for in many logs the original centre is well to one side of the mature log. Some trees 

 have limbs on the congested side only 6 to 8 feet long, while on the free side they are 15 to 20 feet long. 

 The maintenance of a good head is important from a forestral point of ^^ew. . . . 



From the study of the annual rings, then, we may conclude at present that the Mountain Ash reaches 



its maturity between the fortieth and fiftieth years ; but we are not entitled to conclude that the tree is 



then fit for milling. In view of the fact that in the future a large proportion of this timber wi\\ probably 



find its way on to the market in a dressed and seasoned condition, the tree cannot be said to be fit for 



E 



