KAURIS ON SPURS

Evening Post, Volume CXXIII, Issue 47, 25 February 1937, Page 10

KAURIS ON SPURS

PREFERRED SITES

SURVIVAL STRUGGLE

DENSE SHADE HATED

Is a kauri forest doomed to die eventually through lack of young trees to replace the old—that is, through lack of "regeneration"?

■ It is hoped that this question can be answered in the negative. That hope I is expressed in the New Zealand Jour- : nal of Forestry (Te Kura Ngaher,e) by - C. T. Sando. The Journal is published annually by the New Zealand Institute . of Foresters, and the fact that it con- ; tains such articles as this on the kauri i tree, summarising information to date, ; is sufficient indication of the national 1 importance of the Institute and its i Journal. BROADLEAFS MAKE A BAD SEED-BED. [ What are the obstacles to natural reL generation of a kauri forest? One obstacle is that the undergrowth of broad- ! leaf plants (taraire, kohekohe, and others) and tree ferns either prevents germination of kauri seed or suppresses the kauri seedlings, by creating too dense shade. . . , • Like certain other native species the kauri, in order to germinate successfully, needs shelter but it also needs light. It needs a shelter that does not mean dense shade. When a cultivator of native plants in a garden is trying to germinate and grow a species his job is to secure in that part of his garden such nice adjustment of light and shelter as the species requires. He will deal accordingly with the sheltering vegetation, and will regulate the light and shade it provides; he will act as the occasion, and the growth of the species, and, other circumstances require. j In Nature the same nicety of adjustment cannot be secured, or cannot be secured at reasonable expense; but measures in the way of silviculturai treatment that will be successful in the kauri forest, and not too expensive, may be found. NATURE SELECTS SPURS. Nature herself points out where things are bad, and where things are good, for kauri germination and regeneration. In some places dense shade produced by the broadleaf (taraire-kohekohe) association and by. tree-ferns (mamaku and punga) prevents germination of kauri seed; but "on spurs where the growth is sparse, but where there is sufficient shelter, kauri regenerates prolifically." Observe here the medium between a growth that gives too much shade and a growth that gives insufficient shelter. On these spurs Nature strikes the desired balance, and kauri regeneration is prolific. In such suitable natural situations the kauri's own efforts to regenerate itself have been so successful that on a plot one-tenth of an acre in extent as many as 1300 seedlings have been counted, "all welf established." Mr. Sando adds: "It is hoped that by assisting the development of these conditions in future we will be able to reproduce kauri sufficiently at least to maintain the present area and possibly to extend it." KAURI FORESTS MAINTAINABLE. Assuming that the writer means maintenance and possible extension of the present' area of kauri forest, his pronouncement is notable and will be welcomed by all persons interested in the perpetuation, in forest as well as garden, of a noble tree. Mr. Sando has many other interesting things to discuss, such as measures to assist the dispersal of kauri seed by natural agencies. The silviculturai treatment that he has in mind includes measures "that will prevent complete removal of the ground cover, and will also provide for sufficient kauri trees to be left to distribute seed all over the area. Care will be necessary to prevent removal of all the surrounding' shelter from these trees on exposed sites, as sudden isolation of the trunk may cause death within a very few years." He regards manuka as a nurse tree for kauri, and suggests the use of such nurse-trees to provide the conditions, required for kauri germination and to suppress the undesired broadleaf plants and tree-ferns. The kauri seedling in the first place "develops best under light shade, but, once it is established, the more full light the better, as long as drying winds are kept out." Hence, as the seedlings establish themselves, "liberation cuttings round the seedlings" are needed.

The alternative to natural regeneration is large-scale planting of kauri. But "no large-scale planting scheme is sufficiently far advanced for any comments to be made on the degree of

success."