Fast Growth of New Zealand Timber-Trees.

Forest and Bird, Issue 40, 1 May 1936, Page 16

Fast Growth of New Zealand Timber-Trees.

(By the late Sir David Hutchins.)

Forestry in New Zealand has been misjudged by the entirely erroneous idea that the New Zealand native timber-trees grow more slowly than ordinary timber-trees of other countries. I find that most of the timber-trees of New Zealand grow faster than the timber-trees of Europe and America — rimu and kauri, the two chief timbers, decidedly faster. According to published returns, New Zealand timber-trees grow some 50 per cent, faster than two of the chief native timber-trees of South Africa. Nearly all the American timbers grow rather slower than kauri and rimu, some much slower.

The mistake regarding the growth of New Zealand trees has arisen from two causes —(1) Comparing trees such as kauri, rimu, and totara, of the dense evergreen forest, which generally grow badly out of the forest, with certain quick-growing exotics —Insignis pine, eucalyptus, and wattles —of the open forest, which grow well in the open, and which have been picked for rapid growth in countries with much larger forest floras than that of New Zealand.

(2) It has been assumed that the profitable cut-ting-maturity of New Zealand trees is that at which they are now felled. In the Forest Commission’s Report of 1913 is given a cross-section of a totara tree 8 ft. in diameter, and a diagram showing that, from a computation of the rings, it is 416 years old.

The conclusion intended to be drawn is that it takes 416 years for a totara to mature.

This is very misleading. Thus the Californian redwood in virgin forest lives from 1,300 to 1,750 years ; but the most profitable cut-ting-age is fifty to eigthy years. Douglas fir lives 450 to 750 years in virgin forest, while in English plantations it is cut at forty years.