BACTERIA NODULES

New Zealand Times, Volume XLVII, Issue 10846, 11 March 1921, Page 6

BACTERIA NODULES

ON NEW ZEALAND CONIFERS.

PROVISION OF NATURE.

EXPLAINS RAPID GROWTH.

What in its most important bearings is probably a new fact in regard to many, if not most New Zealand timber trees was pointed out to a “New Zealand Times” representative yesterday by Professor E. H. Wilson (assist-ant-director of the Arnold Arboretum, Harvard University, T7.5.A.). Many people, especially those most interested in gardening (said the Professor) are aware that the roots of peas, beans, lucerne, and other leguminous plants, are- prov ided with nodules of bacteria which extract the nitrogen, etc., from the Goil t and thus greatly assist these plants in deriving their sustenance from the earth. Professor Wilson showed that the roots of the matai are similarly equipped with bacteria, as also are the rootlets that form the peaty surface (sometimes two to three leet deep) of the earth in our New Zealand forests. On the roots of the tiny matai trees, which he exhibited, and also among the roots of the peat, he had secured, for demonstration and.investigation purposes, the nodules were very plainly visible to tiie naked eve. “The existence of these nodules/’ stated Professor Wilson, “has no doubt been knpwn for many years, hut I question if the full significance and importance of them has hitherto been recognised. It was Captain Mclntosh Ellis, your Director of Forests, who called my attention' to it during pur forest-inspection tour of the South Island. As he suggested, there can he no doubt that - these nodules help materially to supply the trees with the universal salts so necessary for their growth. That accounts at once for the rapid growth of your timber trees in your forests, and also their comparatively slow growth when planted out in gardens. The bacteria nodules are not present in the garden loam, and thus the native trees planted in gardens are starved of their natural nourishment and their growth is necessarily - retarded. These nodules are in the peaty soil, and when the hush is burnt off, the peat dries up and is also burnt in its turn, thus destroying the nodules which gather on. the rootsof the trees and help them to grow. That shows the great danger of allowing the present reckless burning-off policy tc continue. “The peat, to the thickness sometimes of three feet, or even more, rests on the hard pan, and you never find the roots with the nodules in the hardpan. Our forest trees in the Northern Hemisphere have not got this provision in the way of ‘ bacteria nodules; and hence, doubtless, the reason why your native forest trees grow so much more quickly than ours. “Your trees axe not slow-growing as was so long thought to be the case- I should add that the nodules you have s seen are found only on your native conifers, pines, or needle-leafed trees, not on the broad-leafed trees; hut the conifers—kaun, rimu, totara, matai, and so on—are your- best timber trees. The character and use of these nodules is now being thoroughly mveotigated by skilled scientists; so that all . the facts about them may j lB , ascertained. It. is a really wonderful prow sion of nature.”