Chapter XXI. — Stocking and Scour
Stocking and Scour.
The difference between Tutira of '82 and Tutira of 1920 is the difference between youth and age: the face of the one smooth, that of the other wrinkled and lined. In the early days of the station its surface was unmarked by paths; now it is seamed with tracks. Before the arrival of the European with his domesticated breeds or animals, save for a few Maori footpaths the station was an untrodden wild: it was without path or track—in the language of Scripture, void; its surface is now a network of lines; it is reticulated, like the rind of a Cantaloupe melon.
In a previous chapter surface alterations of a minor kind, consequent on the stocking of land, have been considered; in this we can explain briefly certain larger effects. A single sentence—one is sufficient—will make clear to the reader what has occurred: the countryside has been transformed from a sponge to a slate. In this vast change the sheep, modifying the run with subconscious care to his peculiar requirements, has been the prime artificer. Nor, moreover, are these operations local; everywhere the flocks of the colony are transforming it with teeth and toes, crumbling it towards the sea. To visualise the magnitude of the general effect, the reader has but to compare the size of Tutira with that of New Zealand, the numbers of the Tutira flock with the number of sheep in the Dominion. He can then in part picture the alterations consequent on the importation of stock. This, however, is the story, not of New Zealand, but of Tutira; except to follow to the sea one of the rivers that rises in its hinterland—otherwise I could not illustrate ultimate results of scour—I shall confine myself as always to facts page 199 from the run. A previous chapter dealing with fern-crushing has shown in detail the destruction of the ancient vegetation of the run by sheep. The reader will remember how, during the first year of heavy stocking, the vast thickets of tutu which used to grow on the southern and eastern slopes were annihilated, how the bracken lost firstly its exuberance of growth, then became stunted in height, and ultimately in many parts perished. With the annihilation of these tall growths and others that succeeded them, the ground was no longer shaded from sun, no longer sheltered from the elements. Its naked surface was in summer-time burnt into dry dust, in winter beaten upon by torrents of rain.
The slipping of the marl hills on eastern and the subcutaneous erosion of central and western Tutira have also been described. These processes yet continue, and will continue; but in addition there has been established by the tread of sheep a new kind of wear and tear. The surface of the central station, once as absorbent as a sponge, now supports tens of thousands of sheep-paths, each of them acting as a shallow open drain. They are, moreover, so toughened and puddled with pulverised sheep-droppings that even after the heaviest of deluges they continue to rush off flood-water. I have seen them washed so perfectly clean of dirt and dust that the blanched, flaccid, fibrous roots of grasses and weeds showed up white like thread. Down these miniature gutters, grit, dust, and gravel are carried wholesale. Except on the flattest portions of central Tutira, the bed of every creek, rivulet, and rill has been metalled by the shingles and sands crumbled into it by sheeps' feet, or blown and washed down by wind and rain. Creek crossings, at one time barely capable of supporting a man on horseback, can now be negotiated by a loaded dray. Immensely increased quantities of material have found their way to the main streams too. The fluctuations of the streams themselves are more marked: there is a higher rise in flood, a lower fall in drought. Instead of a permanent percolation from the whole body of the countryside, there is a violent brief surface scour. Even locally the results of stocking have not yet been fully recognised. Loss of bridges and culverts, recurring flood after flood, cannot be due to miscalculation of catchment area or to lack of information in regard to rainfall; it is owing to insufficient allowance for the hardening of page 200 the countryside, for the enormous multiplication of open sheep-paths that rush off the surface water.1
The cumulative effect of the work of sheep is in truth nowhere more apparent than on the alluvial lands of the river-mouths. They suffer a twofold deterioration—positive and negative; firstly, deposition of grosser grit and coarser sand—stuff in former times trapped by the riverside vegetation of the upper reaches now destroyed by fires and stock; secondly, loss of the finest forest mould held in suspension during flood. It is no longer allowed to settle in comparative calm amongst rank vegetation standing knee-. or neck-deep in flood water. It is wasted now—carried direct to the ocean. In addition to cessation of income from the interior, there is an extravagant expenditure of capital banked, of alluvium deposited in former centuries. Nor does the harm done by scour cease even then; crosswinds blowing on the wider river-mouth raise wavelets of considerable size, whose lapping still further devours the banks.
Whatever may be the fate of large alluvial areas, smaller valleys run serious risks from breaching of ancient banks and from super-position of valueless sand, grit, and rubble.
We have now to consider, not indeed a minor, but a much less conspicuous aspect of stocking and scour. It is the permanent hardening of the crust of the ground and its effects on grasses. The surface, no longer subject to any natural process of mulching, has become less friable, the pounding and stamping of stock has affected page 202 the quality of the turf. There is no question but that the best fattening grasses are disappearing, or have disappeared. Though it is true that the constituents necessary for rye and clover are, after a couple of seasons, exhausted on the hungry pumiceous lands of which the trough of the run is largely composed, such is not the case in regard to the best marl surfaces of parts of eastern Tutira. Far less does it hold of the magnificent soils of Poverty Bay and of great parts of southern Hawke's Bay. In those districts, certainly, the gradual displacement of ryegrass and clover cannot be ascribed to exhaustion of the land. It is due to changes of the surface whereby certain natives are benefited at the expense of their alien rivals.
On an iron surface, however rich, germination is less easy; a sufficiency of moisture, moreover, in drought is unobtainable. I have described elsewhere how the sites of old Maori workings were in early days marked by grasses such as Micrœlena stipoides and Danthonia semiannularis. They grew where the surface had been stamped hard by man; now they grow where the surface has been pounded and trodden by sheep—that is, over nine - tenths of the province. A general deterioration in the turf has begun, entailing in its turn readjustment of the type of animals bred thereon. I do not say this is the sole reason responsible for the general change throughout Hawke's Bay from the Lincoln to the hardier Romney Marsh sheep; undoubtedly it is one, I believe the chief, reason. Fodder-plants such as rye, white clover, even cock's-foot, die out or flourish with less exuberance, inferior aliens and comparatively valueless natives taking their place; the flockmaster, adapting himself to the changed environment, breeds a hardier race of sheep.
It would be easy to stretch the links of cause and effect: the hills become like stone; the settler growls as, tipping his correspondence from mail-bag on to verandah floor, he opens an epistle demanding an increase in rates owing to the destruction of bridges. Stock trample hard a countryside 12,000 miles from the great cities of Europe; carpets are softer to the tread,—the coarser Lincoln fleece has been supplanted by the finer wool of the Romney Marsh.
1 Explain it as philosophers may, the country settler soon comes to plume himself on any adverse peculiarity in his environment. To belittle it is to belittle a trouble which in his heart of hearts he believes only he himself is capable of enduring. A landholder in Hawke's Bay, through whose property flows a river, has no need to search for trouble; there it is at his door, so much in mind that it becomes a part of himself until by some strange perverse mental process he becomes proud of its unruly ways, pleased when from time to time a wandering weed inspector or trades union official falls a victim, or a bridge is carried away. No aspersion is more readily resented than one cast on the dangerous depths of a ford, or the flooding powers of a river. After completion of the first bridge over the Waikoau, the work was viewed by a pair who knew Tutira and its weather ways. “How long do you give it?” says one. “The first decent flood,” replies the other. He was not, however, perfectly correct. Only the earthwork on both banks was washed away, the bridge itself remaining an island, intact. The river's hint, however, was taken and a new span added; yet the whole structure was wrecked in 1917. Good old Waikoau!