72 The N.Z. Journal of Science and Technology. [Mar. 
should be taken to increase such capacity. An artificial change in the 
usual procession of events might readily be brought about which would 
result in a different combination of members in the ultimate grassland, 
and such combination might be of greater economic (wool-producing) value. 
The study of sand-dunes with regard to their agricultural capabilities 
may be cited as a further simple example of ecological method and its 
economic importance. Here empiricism is quite out of place. A certain 
method of treatment for a certain sand area may prove efficacious by the 
method of “ Try this, or that, and something good may turn up.” But 
let the result of this system be applied to another dune area where the supply 
of sand is rather greater, the climate rather drier, and the average angle 
at which the sea-wind strikes the dunes rather less oblique : the method 
so successful elsewhere fails at once. But attack the dune problem eco¬ 
logically ; study accurately the tactics of sand when exposed to wind ; 
study also its physical properties, the relation of the natural plant-covering 
of various types of dunes to moving sand, the climate of the area, the 
evolution of the vegetation from that of the unstable sandhills to those 
quite fixed by vegetation, and so on ; find out exactly how Nature works 
under the many conditions that dunes offer ; note exactly the plant-forms 
which can survive different degrees of sand-advance : then, when these 
preliminaries are fully mastered, with some degree of confidence the in¬ 
vestigator can attempt the “ reclamation ” of a dune area, and, adding to 
his ecological knowledge by further observations and experiment, is finally 
in a position to draw up for agriculture those rules for dune culture which 
alone can fully succeed. 
The teachings of ecology as they accumulate will undoubtedly be a 
powerful weapon for advance in agriculture. In Nature the plant must 
perforce bow to the environment—except some change* occurs, its position, 
high or low, amongst its fellows of the plant-community must remain 
unchanged. Thus, so long as an area of New Zealand mixed forest remains 
intact, not one plant of the bracken-fern is to be seen amongst its ferny 
brethren of the forest-floor. A high tree falls, far more light strikes the 
ground — a somewhat drastic change — and within a brief period the 
bracken-fern appears together with other plants rare or wanting in the 
virgin forest. 
Agriculture, however, does not depend upon the slow processes of nature. 
If the reactions of a plant to the outer world be sufficiently known, it 
should be possible to so change the conditions of its environment that its 
frequency in an association could be so increased or decreased as its agri¬ 
cultural value may suggest. There are many ways of bringing this about 
even now, but usually, from want of sufficient knowledge as to the plant’s 
capabilities, or the structure of the environment, they are not sufficiently 
precise. Liming the ground, applying certain fertilizers, fallowing, burning, 
understocking, overstocking—these and many more are means to the end 
in view, but want of exact knowledge makes them but rather clumsy tools 
at best. These various methods resolve themselves, to no small extent, to 
assisting certain plants to overcome others in that struggle for existence 
the correct estimation of which is of inestimable ecological importance. 
And with the advance of ecological knowledge, as fact after fact comes into 
view, it will become clearer not only how but why one species or another 
is favoured in the struggle. 
This brings me to the paramount importance of a study of the ecology 
of pastures. These are of various types, and each type demands special 
investigation. There is no pasture which is perfect, while many are quite 
the reverse. Doubtless vast improvements can be made by one or other 
