FIELD NATURALISTS' CLUB

Dominion, Volume 9, Issue 2583, 4 October 1915, Page 3

FIELD NATURALISTS' CLUB

ORIGIN OF SAND DUNES. The opening of the second session of the Wellington Field Naturalists' Club took place on Friday last at Victoria College, wiien a presidential address by Dr. L. Cockayne, F.R.8., was given. Ho took as lus subject "Sand Dunca, Their Origin, Flora and Control." He began by defining what is technically known as sand, went on to show how sand was formed t>y the disintegration of the rocks: how it was washed down by the rain into the rivers and thence to the sea. From the sea it was brought back by currents, etc., and cast on to the sea shore at points where a - suitable landing was afforded, in talis, way beaches of sand were formed. Tho sand oil these beaches became dry and was driven back by winds, forming sand dunes according to the character and formation of tho land on to which i that sand >vas blown. The importance of ! the sand dune question, he went on to say, should bo brought home to us when we considered that in New Zealand alone over 300,000 acres which were once fertile fields or native forest were now completely covered .by sand. • Even churches, homesteads, etc., "had/been completely buried by EHe of sand dimes. Ihe formation of sand dunes !ho dealt with very explicitly and fully. , He said ii ? 16 CoDb t r ucted on an exact parallel to the formation of the ripples which are to be seen on any sand area. The vegetation of the sand dunes lie dealt with at some considerable length, and ehowed how it was possible finally 'to clothe the sand with so dense a growth of plants that further movement of. that sand was impossible. Let that growth be destroyed, _ however, even if. in only a small limited area, and' very soon the whole dune would again become a bare juoving 'dune, killing all growth before it. Ihe first plants to gain a foothold on sand dunes, he went on. to say, were plants specially adapted by means of their long underground stems and by, their power of forming roots up the stem a3 the sand heaped higher and higher around them. Such grasses were' the silvery sand-grass (Spinifex hirsutus), Man-am grass (Ammophiia arenaria), and Pingao {Scirpus. frondosus). The final aim of sand # dune areas ho said should be afforestation. After the address questions were asked and the advisability of lucerne for sand areas was • discussed. The address was illustrated by over 60 lantern slides, and wjw given before a large and attentive gathering, JDn Saturday afternoon the first field exbursion took place to Lyall Bay, where the >:and dunes were the object of discussion and examination. What was paid at Hte presidential address Dr. Cockayne amply verified ou the dunes. The gathering was a great success and was attended by 33 members of tho club.