1919.] New Zealand Institute Science Congress. 343 
Spontaneous Reproduction of Exotic Trees. 
In order to see what species of trees are suitable for purposes of 
spontaneous reproduction I have taken careful observations of what is 
happening within and outside the plantations of the Hanmer Plains and 
elsewhere. That which takes place outside a plantation indicates what 
trees are likely to increase their numbers under the conditions of the open, 
while that which takes place inside the plantation indicates the regenerative 
powers of the forest after its establishment. 
On some of the North Canterbury sheep-stations, the areas of which 
spread far into the high-mountain country, shelter plantations of exotic 
trees, mainly conifers, were established forty to fifty years ago or more. 
These plantations apparently reached the seeding stage at a very early 
age, and their seeds were scattered broadcast by the terrific north-west 
winds which are such a marked feature of the mountain areas. The 
results of this seeding are apparent in many places to-day, for not a few 
of the offspring of the original plantations are now from 20 ft. to 30 ft. 
in height, and are themselves seeding profusely and reproducing seedlings 
again at a most astonishing rate, so that one may observe at a glance the 
three generations in progress. Standing on an eminence one may trace 
a course of reproduction in a direct line with the north-west wind from the 
[C. G. Christensen, photo. 
Fig. 1.—Natural regeneration of Finns sylvestris. The parent plantation, containing 
some half-dozen “mother trees” of Scots pine, from which regeneration has taken 
place. Main spread of young forest to the eastward; some slight regeneration may 
be seen to the westward of the parent plantation. 
parent plantation, thus pointing to the wind as practically the sole distri¬ 
buting agent. No sign of any reproduction worth mentioning can be found 
to the north-west of any of the parent plantations or trees, a clear proof that 
practically no other carrying agent has been at work in this locality. It 
is desired to stress specially the fact of the wind being the dominant distri¬ 
buting agency, as it will be one of the main features governing afforestation 
of our high country by means of natural regeneration (see fig. 1). 
This spontaneous reproduction has taken place on the Hanmer Plains 
and elsewhere under adverse conditions, and over country abounding with 
enemies to tree-growth. This country is infested with hares and rabbits, 
and heavily grazed with sheep, horses, and cattle, and presents to the eye 
a most unpromising seed-bed, swept as it is by drying winds which parch 
the surface to an intense degree at various periods of the year. This 
regeneration has taken place without any artificial aid and without any 
care or attention from man, and can be seen going on for some distance 
from the parent plantations, showing three generations of trees in the com¬ 
paratively short period of probably less than fifty years, under conditions 
contrary to the findings of the text-books on this subject. 
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