21 
CLIMATIC DISTRIBUTION. 
might suppose that species from inland districts of Australia would be the 
least able to endure our coastal conditions; but this is not uniformly 
the case, as we shall see when we come to describe and discuss the several species 
under trial in various parts of this country. 
PRACTICAL APPLICATION OF RESEARCH. 
If we rightly interpret the truths thus stated, we shall see that nature has 
herself worked out a great climatic distribution of the eucalypts, and that there 
is no appeal against her decree. The question for us therefore now is: How can 
we conform our practice to nature’s law^ We in New Zealand might draw parallel 
lines across the map and so divide each Island into zones; but in this case every 
zone would include several varieties of climate, and the scheme would be useless. 
We can and must cite as many localities as possible where the species we describe 
may be seen growing; but to name and delimit all suitable localities for each species 
would require many months of survey work and a large volume for records. A 
man highly experienced in plant culture will often be able to gauge the climatic 
conditions ot a district from the aspect of existing vegetation; but the great 
majority of people do not possess that experience. However difficult the task may 
be, we must somehow construct a general key or formula that every man may apply 
to his own particular needs and circumstances. 
If we define climate as the sum of those ever changing states due to solar 
radiation and to the earth’s structure and magnetism, we must admit that only the 
scientific man with his instruments can wrestle with the problem as a whole. The 
farmer or tree planter cannot undertake so wide and difficult a task, but must look 
to those adaptations that will ensure success for his own particular enterprise. 
For the eucalypts a scheme is needed that will show plainly where any species is 
likely to grow, how it may be distinguished from other species, and what will 
be its value when raised to maturity. 
The factors that determine the profitable range of a species are temperature, 
rainfall, soil, and the prevalence or otherwise of injurious winds. Of these four 
factors much the most important and yet the most elusive and difficult to assess is 
temperature. 
In the scheme of grouping laid down in the next section of this hook tempera¬ 
ture in the dual and complex meaning of the word, is treated as the master-factor 
dominating all the species and assigning to each its place in the climatic scale. But 
at the same time there is devoted to each species a separate descriptive article in 
which information is given on the following points:—Natural habitat and 
requirements in respect to rainfall and soil; specific characteristics and 
appearance of the tree; rate of growth and ultimate size; texture, quality, 
and durability of the mature wood; and, lastly, the prospect for cultivating 
this particular species in New Zealand. Essential to the validity of any 
such scheme is a supply of seed from parent trees that have in the case of each 
species been correctly named and are of first rate vitality and form. 
