SECTION IV, 1916 [105] TRANS. R.S.C. 
The Quantitative Study of Climatic Factors in Relation to Plant Life. 
By J. Apams, M.A. (Cantab.) 
Presented by C. GorpoN HEWITT, D.Sc., F.R.S.C. 
(Read May Meeting, 1916). 
If one were to choose at random a square mile of territory in 
Anticosti Island, Southern Saskatchewan and Vancouver Island 
and were to compile a list of the native plants in each of the three 
selected areas, a striking difference in the flora would be observed. 
Or, if the areas chosen were situated on an alpine slope and on the 
floor of a valley several thousand feet below, the difference would be 
equally remarkable. The differences might be due to some extent 
to the chemical composition and physical characters of the soil or 
underlying rock but in the main they are to be attributed to the climate. 
In a vague sense every person knows what is meant by climate 
or ‘‘weather’’ but the separate elements or factors composing it are 
interrelated in a very complex manner and rarely remain constant 
for any considerable length of time. If we are to make any headway 
in understanding the relation that exists between climate and plants 
we must as far as possible dissociate the separate factors and study 
them one by one. But when we have done this it will be well to 
remember that the part played by each factor when all the factors 
act together will not be quite the same as we might have supposed 
from our consideration of any one factor acting alone. For example, 
if a certain total amount of heat causes a definite increase in growth 
when the amount of moisture in the soil is sufficient and the sun 
shines brightly each day the result with a deficiency of moisture 
or with a cloudy sky may be quite different even although the amount 
of heat received by the plant may be the same. Nevertheless, a 
careful analysis of all the climatic factors acting at any particular 
locality for a series of years should not only help to elucidate the 
present distribution and structural characters of the flora but should 
at the same time yield useful information as to the crop-producing 
possibilities of the district in question. 
Before considering the various climatic factors that influence 
plants it will be advisable to determine what time-periods may best 
be employed in endeavouring to express in a concise way the total 
effect of each factor. Some units of time may be considered as natural, 
others as arbitrary or artificial. 
