With regard to tanning barks in New Zealand, I beg to remark on the indigenous trees, and also the imported, the cultivation of which would prove highly remunerative, a desirable industry for the Colony, and a good export.
The native trees which contain tannin are (1) the Tawero, synonymous with Towai {Weinmannia racemosa, Forst). (2) Whinau, (3) Toatoa, (4) Tawai, (5) Makomako, Yellow Kowai, and others.
The tannin in our New Zealand Trees certainly does not abound, but it is amply made up for by the introduction of the numerous varieties of the Acacia from Australia.
The whole tribe of Acacia medicinally contains a valuable astringent, consequently tannin more or less in the various species of which now more than 300 sorts are known to science. Those of which the bark for tanning is used in Australia are but few sorts, such as are large growing trees, and of easy access. The undermentioned are commonly used in different parts of Australia and New Zealand, and exported^ in considerable quantities to England:—
The first is generally known as the Silver Wattle (dealbata), now so plentiful in the North Island; also the falcata, the melanoxylon, or black-wood, and the mollissima, woolly-leaved. All these are to be seen in Napier gardens.
I am informed that in Victoria, the Silver Wattle seed is sown there as a speculation; that in three years the trees are worth £5 per acre—the bark for tanning purposes, the wood for fuel. The great advantages of these trees is, that when the seed is once sown, it does not require renewal, as it is supplied in the future by suckers from the roots and falling seed.
The value of Acacia bark for tanning purposes in New Zealand is about £8 per ton.
If these trees were planted along our railway lines where they are fenced, it would no doubt be a large source of revenue, and amply repay the outlay; they would also prove shelter from the sun, the wind, and the dust. The Acacia has already been tried with advantage in Algeria, and the Home authorities intend cultivating it in the island of Cyprus.
Mr. Colenso related the first use of the barks of New Zealand trees for tanning purposes, which took place at Ngunguru (between Whangarei and the Bay of Islands), in the years 1839, 1840, and 1841, which had come under his special notice while living at the Bay of Islands, and often travelling in that district. This was the first place in New Zealand where hides were tanned for leather, the whole process was particularly primitive. Extracts of those several barks there used, with specimens of the trees producing them, he had sent to Sir W. J. Hooker, the Director of the Royal Gardens at Kew, long before New Zealand became a British Colony.
