[Proc. Roy. Soc. Victokia 30 (N.S.), Part I., 1917.] 



Art. r. — Timber Production and Grrnvth Curves in the 

 Moivntain Ash (EiLCulyj^tus regnans). 



By R. T. PATTON. 



(Witli Plates I.-II.) 

 [Eead April 12th, 1917]. 



It has been said that Mountain Ash will mature in 40 years, and 

 will give in this time a butt of from 2 ft. to 2 ft. 6 in. 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 ft. super 

 per acre. In order to test 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 all the forest 

 noAv being cut is over ripe, and consequently many trees are hollow. 

 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 large 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 which 

 the annual rings were clearly defined. The measurements were 

 taken to the eightieth (80th) 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 

 125th 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. This is shown in Fig. 1. In this graph the average width 

 of ring for each decade is shown. The annual rings were measured 

 in groups of ten and tlien averaged. This was done in order to 



2 



