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Salient. An Organ of Student Opinion at Victoria College, Wellington, N.Z. Vol. 8, No. 12. September 19, 1945

Bush at Alpha Threatened by Serious Erosion

Bush at Alpha Threatened by Serious Erosion

Some may consider erosion in economically useless mountains of no importance. Due to this error, the removal of the soil and subsequent death of the trees or tussock, the water holding capacity of the hills is reduced and so the modern floods.

Superficially, erosion is not very-marked on Alpha, only a few small slips, but there are areas of large dead forest especially on the southern and eastern sides and on Quoin. The level of the forest is 400 feet lower than twenty years ago and the larger trees are killed for another 100 feet.

Over much of this area, and indeed all the mountain, 18 inches to 2 feet of soil has been lost, so it is back to the bed rock except for a light layer of frost-riven fragments. This maybe seen by the roots on old stumps, soil backed up around stumps and rocks.

This erosion is largely due to deer. Evidence of this is that (1) deer are very plentiful in the worst areas, which always have a sunny aspect; (2) on slopes with a southerly aspect the bush is 200 feet higher. On the western slopes, due to the prevailing wind and steepness, the bush has not been killed to such an extent; (3) the process can be seen in an early stage on Hell's Gate. On the western side of this hill one is struck by the mass of dead leatherwood, their trunks stark white after losing the bark. On the eastern side the larger birches are now being blown over. In twenty years Hell's Gate will be above the snow line.

Once the growth has been killed here it takes a long time for the wound to heal. It is interesting that the mountain cabbage tree is a pioneer in healing the eroded areas. As deer and opossums are the two mammals which live up high and do the damage, it is necessary that energetic measures be taken to exterminate them.—J.R.J.