Sixth Meeting: 26th September, 1910.
Dr. R. Briffault, President, in the chair.
New Members.—E. A. Price, J. W. Stewart, R. Leslie Stewart, J. Wilson.
Lecture.—The Rev. Archdeacon Walsh gave a lecture on “The Effects of the Disappearance of the New Zealand Bush.”
The lecturer sketched the causes of the destruction of the forests—cattle, fire, and the axe of the bushman. Cattle roam through the bush and destroy the undergrowth, and fire follows, immediately afterwards. The consequences of this deforestation are great and far-reaching, and are of two kinds, climatic and topographical.
Dealing with the climatic changes, Archdeacon Walsh said that after two or three fires had passed over an area of land it left the soil very poor and scantily protected with vegetation. It became easily heated by the sun, and then the air was heated by radiation from the earth, giving rise to winds which parched up surrounding lands, prematurely ripened crops, and rendered other areas liable to be swept by fire. When the forests were near the sea, their destruction left the way open for sea-winds, which carried salt spray many miles inland, and killed still more vegetation. In northern Taranaki and at Hokianga it had been found that severe frosts, hitherto unknown, had followed deforestation, owing to the loss of protection from cold winds from the sea. Although in many districts every possible acre was being cleared in order to allow for the grazing of dairy cattle, it would have been better had a reasonable amount of bush been left standing as protection.
As for topographical results, when heavy rain fell on forest land most of it was held by the trees and evaporated again. When the bush disappeared the water began to flow on the surface causing erosion and landslips. This erosion gradually filled the water of the rivers with solid matter, which was deposited on the bottom, raising the bed until the river overflowed, and destroyed wide tracts of land by silting and by eating out other courses, and eventually caused the formation of harbour bais.
In many countries foresting work was carried out to a large extent, but the methods generally adopted were not at all applicable to the New Zealand bush. It was impossible to thin New Zealand forests. Once this work were started, fire must follow, and the bush be totally destroyed. And no amount of reafforestation could make up for the damage which had already been done.
Looking into the future, one could only see the damage already done being greatly increased. Reafforestation was being carried on in a way by the Government, but not at all in proportion to the area which had been wasted. There was no hope that forests at present standing would remain intact. Land must be found for settlers, and as long as there was a demand for timber the sawmiller would be found to attack the bush. Even the present Government reserves were not safe, and would not be until they were surrounded by stout barbed-wire fences, for, once cattle and pigs got into the bush, fire was a natural consequence. Several reserves have already been lost in this way.
Settlers in different parts should be made to keep certain areas always under timber. Thus they would have adequate protection for their remaining lands, while at the same time they would find that they had no more profitable crop than their timber-trees.