Exotic Trees Grown Above Bush Line

Press, Volume CII, Issue 30127, 10 May 1963, Page 15

Exotic Trees Grown Above Bush Line

Exotic tree species had been grown successfully up to 5500 ft in the Southern Alps, far above the bush line. Mr J. T. Holloway, head of the Forest and Range Experiment Station, of the New Zealand Forest Service, at Rangiora, told a conference on erosion yesterday. Only exotic species would be of use in stabilising eroding high country, because native species had by and large completely failed in this, and there were no indications that the natives would come back within a reasonable time, he said. “Some of these exotics have been so successful that they could be even more vigorous lower down, and a good number have been completely wiped on this score because of their weed-potential,” said Mr Holloway. “In fact, there are some things we have tried which

could so easily turn into rampant weeds that I am not even going to mention their names, ‘in case some fool brings them in and lets them loose here.”

Of the 280 species which had received a trial at the station’s outpost in the Craigieburn range over, the last 10 years, six to 10 had Shown good promise of being useful for protecting forests without having any great weed-potential, Mr Holloway said. Whenever plantings of exotics were made, the most hardy native species, mountain beech, was planted alongside as a control. The successful exotics could stand conditions far more rigorous than any native tree.

To date, by far the most successful species tried, apart from those almost certain to become weeds, was lodgepole pine. Experiments now under way were aimed at minimising its weed potential and maximising. its possible usefulness by observing its reaction to various aspects, altitudes. and soils, and discovering the differences between the various strains and subspecies.