372 The N.Z. Journal of Science and Technology. [Dec. 
The measurements given, as taken by the writer, are those of straight- 
grown trees ; none are of branched or ill-grown ones. 
The data taken from the work of the late Mr. W. N. Blair, though 
shown in table E, have not been included in the average, because the 
measurements are no doubt from fully matured trees, grown in Otago, of 
a size greater than would be aimed at in practical forestry, and their 
inclusion might therefore be considered a somewhat unfair comparison. 
Table E compares the growth of indigenous trees in New Zealand with 
the growth of foreign trees in foreign countries ; table F compares the 
rate of growth of indigenous trees with that of exotic trees grown in New 
Zealand; and table G gives the detailed averages of thirty-four species of 
gum-trees, the combined average of which is shown in table F. 
The accompanying diagram displays the relative diameter-growth in a 
given time of the kauri, average of thirty-four species of valuable gums, 
redwood (Sequoia sempervirens ), and Finns radiata (P. insignis). 
Diagram showing the proportionate diameter-growth in a given time of—-A, the kauri; 
B, average of thirty-four species of gums ; C, redwood ; and D, Plnus radiata. 
As, owing to the difference in height and taper of the different kinds 
of trees, the diameter-growth does not always indicate the true comparison 
of growth in bulk, the following table is given of cubic contents, computed 
from actual measurements of height, taper, and diameter. 
Table of Cubic Contents of Trees 35 Years old. Board Feet. 
Kauri : Based on Cheeseman’s average of diameter-growth and 
actual height-measurement . . . . . . . . 100 
Redwood : Based on the average diameter, height, and taper of 
six trees . . . . . . . . . . 1,400 
Gum : Based on average of thirty-four species given in table G 
and applied to actual height and taper measurements . . 1,400 
Pinus radiata : Actual measurements of trees cut into mill-logs . . 2,200 
In actual practice the theoretical number of board feet would not, or 
might not, be obtained, but the quantities are in actual proportion. 
Whilst none of our native forests occupying high and extremely rough 
and poor country should on any account be destroyed, and all the millable 
timber that still remains should undoubtedly be milled under strict regu¬ 
lation and made last as long as possible, it seems to 4he writer that the 
information contained in the tables shows conclusively that it would be 
an utterly hopeless undertaking to attempt to provide even a small portion 
of our future needs in timber by growing native trees. 
