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THE VERTICAL GROWTH OF TREES. 
The following two letters from The Surveyor (the official organ of the 
Institute of Surveyors of New South Wales) for 31st December, 1904, and 28: h 
February, 1905, respectively, refer to a matter that often forms the subject of 
controversy, but which has rarely been the subject of actual experiment. The 
question is often put in this form—Given two nails driven into the same tree at 
different heights, would they become further apart as time goes on ? 
It will be seen that American experiments answer this in the negative; 
actual tests are being made in the Botanic Gardens, Sydney, on various trees under 
the supervision of Mr. Cambage. 
(1) Ml - . T. W. Fowler, of the Melbourne University, writing with reference to Mr. R. T. McKay’s 
lecture on the Murray River, has touched upon a very interesting feature in regard to the vertical growth 
of trees. I had previously drawn attention to the great height of flood marks, as exemplified by logs and 
roots caught in the forks of trees 40 feet overhead. The particular spot I had in view is on the 
Lachlan River above Cowra, where the valley is considerably confined as compared to the spreading flats 
lower down. It was stated locally that the highest marks were the result of a flood about 1874. There 
are no records available of flood heights on the upper reaches of most of our rivers, hut the highest 
flood at Gundagai, on the Murrumbidgee, reached 39 feet 6 inches in 1853, according to the records at the 
Sydney Observatory. 
The question raised by Mr. Fowler, however, is whether, owing to upward growth, such marks as 
logs caught in branches can always be regarded as indicating, in their present positions, the height of the 
flood by which they were deposited, and he quotes a case to prove that the vertical growth of a tree 
extends to the trunk, and is not restricted to a prolongation of the branches. 
The point is one that might well receive the attentioiL of some of our surveyors who have fixed 
stations in the country, and a very valuable set of observations might he obtained, which would augment 
the somewhat limited available statistics in regard to tree measurement in Australia. In 1891, Mr. H. C. 
Russell, F.R.S., in a paper read before the Royal Society of New South Wales, drew attention to the want 
of information on this subject, and stated that in older countries the rate at which various trees grew had 
been cai-efully watched for many generations. He also gave the l'esult of an investigation he had 
made, but which was confined to circumference measurements only. In 1897, Mr. J. H. Maid< n, F.L.S., 
in his Presidential Address before the Royal Society, also referred to the necessity which existed for 
ascertaining the heights and trunk-diameters of various kinds of trees, with a view to preparing a record 
of the rates of growth of our Australian trees. In the August number of the Agricultural Gazette for 
1896 are a series of reports from Forest Rangers relating to the rate of growth of indigenous forest trees. 
The particular point, however, which has now been brought under notice, is one which does not 
appear to have received much consideration. Although it seems probable that the stems increase in length 
below the limbs, it must not be overlooked that among straight-growing saplings there are always many 
small dead and dying branches below the lowest green one, thus indicating that where a tree has a straight 
branchless bole for, say, 50 feet, it does not follow the first limb was always the lowest. Our Eucalypts, 
in a well-sheltered coast forest, run up very quickly, and rapidly lose their twiggy branches, while the Pines 
( Callitris ) retain them, so that it is only in old age we find the latter species with clean holes. In the last 
number of The Surveyor, Mr. District-Surveyor Walker quotes an interesting instance of where some old 
blazing appealed uniformly high on the trees, and it does seem possible, in the absence of a knowledge of 
the conditions at the time of, and subsequent to, the marking being effected, that the rich flat upon which 
the trees grew may account for the rapid vertical growth of the stems. In my experience nothing has 
been noted to prove this vertical growth below the branches, old blazes and shields having generally been 
found at about the usual heights. 
The matter appeals most of all, perhaps, to those surveyors who use the base of a growing live as a 
referring mark for levels, and for many years the question of the variability, or otherwise, of bench marks 
in such positions has exercised the minds of those using them. Possibly the point has been tested ; and 
if so, particulars of the result would be interesting to the members of the Institution, and at the same 
time be a valuable addition to the literature on the subject.—-R. H. Camuage. 
