MORE LANDSLIPS

Dominion, Volume 35, Issue 250, 20 July 1942, Page 8

MORE LANDSLIPS

Theory About Planting Of Shrubs ORIENTAL BAY SUFFERS Large masses o± rotten rock fell from the cliff face of Fitzgerald Point, Oriental Parade, Wellington, on Saturday rooming. The heavy rain which fell throughout the morning converted the soft spoil into a stream of thick yellow slush. The properties invaded by the slip are No. 170 (owned by Mr. T. A. Wells) and Nos. 168 and 166, semi-de-tached one-storied wooden cottages, owned by Mr. John Cameron. The veranda at the rear of No 168 has been crushed tn and the backyard is tilled with a big .slanting pile of rotten took. It is not possible to form any definite conclusions as to the prospects of future landslips at this point. The latest fall has left a verticil. face of r-ck about 20 feet in height at the top. The slide below that snows outcrops of what appears to be firm rock showing through a little loose spoilShould tlio top vertical face prove friable other falls may be possible; it not, it may prove as good holding ground as other parts of this face nearer town. Theories as to Cause. There are two theories as to the immediate cause of the slip a' Oriental Parade. One is that the existing face of rotten rock may nave become - disturbed by the big earthquake, creating cracks for the admission of water dining last week’s heavy weather. Another theory is that, contrary to a fairly general belief, the planting of shrubs and trees oil an almost vertical cutting is creating trouble, for future generations. One of the city corpotation’s staff of engineers is positive about the effect of growth on cuttings: During observations made over 25 years in Wellington, he says that when there is a slip in a cutting, it invariably occurs years after it has been planted, when the roots, sometimes 15 feet in length, have had time to penetrate and expand between layers of rock, and even splitting rocks, so making little tunnels for the lodgment of water. The cliff now eroding was planted by Mr. James Edward Fitzgerald, C.M.G., formerly Comptroller-General, who resided at the site of the Monastery of St. Gerard (Fitzgerald’s Point) for" 25 years. The hill-face was eut away for a double purpose, to make a wider Oriental Parade (with a strip of level land for house construction) and to provide spoil for the first. Te Aro reclamation, is soon as tha’ job was done Mr. Fitzgerald, anxious to cover up the sear left by the excavation, developed the habit of scattering seeds from ’ above in wet weather to make sure they would find a place in the softened earth. They did. Up till last year the face showed an almost luxuriant" growth, including some sizable trees, and big cactus plants, a mass of which came down in the slip of last October. In the debris of last week was the root of a big macrocarpa, three feet in thickness. Possibly Mr. Fitzgerald held to the theory that tree-roots act'as a binder - but the modern theory is that on an almost vertical face they become a menace after a few years. A 'J aihape man, who inspected the slip on Saturday, said that if steps were not taken to kill or remove the cacti and other shrubs on the face further trouble was inevitable.