Art. XXXIII.—Notes on the Occurrence of Kauri-gum in the Kahikatea Forest at Turua.
[Read before the Auckland Institute, 5th October, 1896.]
Kauri-Gum is so intimately associated with kauri forests, or open lands where kauri forests must have once existed, that to find it in one of the oldest existing kahikatea forests seems to me worthy of being placed upon record.
The Turua Forest lies between the Waihou and Piako Rivers, and consists chiefly of kahikatea. A few trees of rimu and matai are occasionally met with, and two or three young kauri-trees, measuring about 30in. in diameter, have been found. The kahikatea-trees are generally large, some of them attaining to 8ft. in diameter, while many measure from 4ft. to 6ft. Captain Cook, who mentions this forest, found kahikatea-trees 19ft. 8in. in circumference, measured 6ft. from the ground. One, which I believe was measured by him in 1777, And which now girths 23ft., has been preserved.
During the very dry summer of 1890 a fire ran through the old bush-workings, as well as a portion of the adjoining land, on which manuka, toetoe, and harakeke were growing. In order to take advantage of the burn, some drains were cut through the burnt country, and while digging the drains the contractor came upon several patches of kauri-gum. This led
to a search being made for more, with the result that up to the present time fully 100 tons of very superior quality gum has been secured. The gum has been obtained in the open country adjoining the forest, as well as in the forest. Roots and portions of the trunks of kauri-trees have been found while searching for gum. The greatest quantities of gum were got in low-lying places and wet holes. As much as half a ton has been, taken from a place about 12ft. square. In places it was found near the surface of the ground, but generally it was got at a depth of from 2ft. to 4ft. There were many indications, such as charred pieces of gum and timber, that fires in the long long ago had destroyed both the forest and much of the gum.
Although the Maoris had previously obtained small quantities of gum in the open country, they appear to have been ignorant of its existence there in any quantity, and I think they never thought of looking for it in the kahikatea forest. They knew, however, of the remains of kauri-trees; and the block on which the gum was first discovered after the fire, and from which a great quantity was taken, is called “Te Kauri.”
It is well known that the kauri grows in dry hilly country. I am not aware of its being found anywhere in such low-lying ground as the Turua lands now are. This would seem to indicate that this land was once considerably higher than it now is, or kauri in such quantity would not have grown. Captain Hutton, speaking of the Thames, says, “The land in this district at one time sunk to about 10ft. or 12ft. lower than now, and subsequently has again risen to its present level.”
How long it is since Turua was covered with kauri instead of kahikatea no one can tell, but it must be a very long time, as I estimate that the large kahikatea-trees are not less than a thousand years old.
So far only a small area of the Turua Forest has been prospected for gum. The undergrowth is so dense that it is not possible to search for gum until a fire has been through, and fire will not run in virgin kahikatea bush—in fact, it is only in very dry seasons that it will run through the old workings. It is quite possible, when the bush has been cleared, that the agriculturist may, in digging his drains, find more of this valuable commodity.