1919.] Maxwell. — Growth of Trees in New Zealand. 371 
RATE OF GROWTH OF INDIGENOUS AND EXOTIC 
TREES IN NEW ZEALAND. 
Comparison of the Rate of Growth in relation to its bearing 
on Forestry. 
By E. Maxwell, Opunake. 
The growing recognition of the approaching world-wide famine in timber- 
supplies, and the fact that the prodigal waste in the past of the once great 
and valuable forests of New Zealand has brought these forests within a 
very few years of practical extinction, placing this country in a much worse 
position than those where reasonable forethought has been exercised, makes 
it all-important that forestry operations in this Dominion should be so 
conducted as to fill the place of the fast-failing natural supplies as rapidly 
as possible. 
Trees that will under ordinary conditions produce the greatest quantities 
of timber per acre, of the various kinds required, in the shortest time, must 
be grown in preference to those which, though possibly of greater value, 
take longer to grow, and which will produce less timber to the acre in a given 
time, and to such as are oversensitive to locality, climatic and other condi¬ 
tions, and also to such as are for various reasons more costly to raise and 
maintain. 
On the subject of our native timber-trees much has been recently said 
and written as to their suitability for future forestry operations. Their 
supposed equality in rate of growth to that of exotic trees has been put 
forward in many quarters, some of which might be supposed to be sources 
of absolutely reliable information. The relative density of growth has not 
—at least, not prominently so—been referred to, probably for the reason 
that it appeared obvious to all, or nearly all, that many of the exotic trees 
have in this the advantage. This may be questioned by some ; for, though 
there are ample data available in this connection as to exotic trees under 
all conditions, there are not many so far in regard to the indigenous trees 
in systematic plantation. If the difference in the rate of growth was proved 
to be substantially in favour of the indigenous trees the degrees of density 
of growth of one or more of them in a few instances under special circum¬ 
stances might become a factor to be reckoned with ; but, on the other hand, 
if the rate of growth of exotic trees is very much greater, then nothing more 
than is now obvious need be known as to the relative density. 
The writer, with the desire to help to set at rest doubts as to which— 
the indigenous or the exotic trees—are the more rapid growers, submits 
the accompanying tables—E, F, and G—which are summaries of many 
other tables compiled with the object of setting out as much information 
of direct value on the subject as the writer has been able to assemble up 
to the present. 
In all cases the data as to the rate of growth from which tlie tables 
have been compiled have been reduced to the average number of years 
in which, in each instance, it takes a tree to grow 12 in. in diameter, thus 
eliminating the confusion of varying ages and sizes, and so displaying a 
direct and common basis of comparison. 
