Cheeseman. — Aye and Growth of the Kauri. 13 



diameters and from different localities. In this manner alone can a reliable 

 average of the rate of growth be obtained. It is true that numerous 

 references to the age of the kauri have been published ; but apart from some 

 on the rate of growth of planted trees, these consist either of vague state- 

 ments to the effect that mature trees are of immense antiquity, or of equally 

 vague assertions that they attain an age of several thousand years, periods 

 ranging from three thousand to five thousand years being freely mentioned. 

 My own doubts as to the accuracy of the common belief date back as far as 

 1884, when I counted the rings of growth in a tree 4 ft. in diameter cut 

 down near Whangarei. To my surprise, I found that the tree had only 

 188 rings, or 7-8 per inch of its radius. A few years later I examined 

 another tree at Coromandel, with a diameter of 5 ft. 6 in., which proved 

 to have 280 rings, an average of 8-5 per inch. Other trees were counted 

 from time to time ; but during the last two years I have been able to obtain 

 quite a number of accurate measurements, amply sufficient, I think, to form 

 the foundation of some general conclusions. 



Before proceeding to arrange the measurements in tabular form it is 

 well to give an outline of the plan followed in obtaining them. In the 

 first place, it was soon ascertained that if reasonable accuracy were desired 

 it was necessary to examine the trees as soon as possible after they had 

 been cut down. Even after the lapse of a few months only, the surface 

 of the stump becomes covered with numerous cracks, some in a radial 

 direction, or across the rings of growth, and others tangential, or parallel 

 with them. These tiny cracks greatly increase the difficulty in counting 

 the rings. Again, the surface of the stump dries very rapidly, becoming 

 hard and difficult to plane, necessitating constant sharpening of the tool, 

 while the cracks interfere with the production of a smooth surface. In 

 the majority of cases, therefore, a recently cut stump was selected. A 

 track about 4 in. wide was then carefully planed from the circumference 

 to the pith. The majority of the rings could then be counted without any 

 further preparation ; but in order to render the whole of them evident 

 the surface was either watered or treated with oil or stain, the plan followed 

 depending on the circumstances of the case. On the whole, I have found 

 that linseed-oil well rubbed in along the smoothly planed track was a 

 perfectly satisfactory mode of treatment. Taking the pith as the starting- 

 point, the rings were usually counted in tens, each group of ten being marked 

 off separately, and the space occupied by it measured. In a similar manner 

 each hundred rings was separately distinguished. The advantage gained 

 by doing this is that when the count is completed it is easy to prepare a 

 chart giving the position of every group of ten or any multiple of ten along 

 the measured radius of the tree, and thus to indicate at a glance any irregu- 

 larity in the disposition of the rings. And it may be mentioned that such 

 irregularities frequently occur. 



Before actually commencing to count the rings the greatest and smallest 

 diameters of the trunk were measured, and the position of the pith noted. 

 It is very seldom that the pith is central. In most cases it is decidedly 

 eccentric, and sometimes largely so. In one instance a tree 5 ft. in diameter 

 had its pith only 1 ft. 3 in. from the southern side of the tree. Usually (but 

 not invariably) the centre is nearest to the southern side of the tree, imply- 

 ing that the cambium layer has been most active on the northern side, or 

 towards the sun. Care was also taken to notice the position of the tree 

 as regards its environment — whether sheltered from the wind or sun or 

 exposed to one or both of them ; whether the tree was crowded amorg 



