WAYS OF THE WILD.

Auckland Star, Volume LX, Issue 52, 2 March 1929, Page 1 (Supplement)

WAYS OF THE WILD.

\ NATURALIST'S NOTEBOOK. THE GBOWTH OF N2. TREES. (By A. T. PYCKOFT4 The growth of car «M*£n» timber trees was the subject of m. recent conversation, during which it was stated that their growth is alow compared with that of ordinary timber trees of other count rice. I find that this is a common belief. The distinguished forester, the late Sir D. E. Hutchim, states, however, that statements to this effect are common, but they will not bear critical examination. Sir David believed 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. He declared that our timber trees grow some 50 peT cent, faster than two of the chief native timber trees of South Africa, and that the same has been found when comparing the growth of New Zealand trees with those of North America. Nearly all the American timbers, said Sir David, grow rather slower than the kauri and rimu, sofno much slower. The mistake regarding the growth of New Zealand trees has arisen from two causes. First, comparing trees such as kauri, rimu and totara, trees of the dense evergreen forest, which generally grow badly when taken out of the forest, with certain quick growing exotic tree*, insignis pine, eucalypts, and wattles-— trees of the open forest, which grow well when planted in the open, and which 'have been picked for their rapid growth in countries with much larger florest floras than that of New Zealand. Secondly, it has been assumed that the profitable cutting maturity of New Zealand trees is that at which they are now felled. From a computation of the rings of a totara eight feet in diameter, it was estimated this tree was four hundred and sixteen years old. The conclusion may be erroneously dra>wn that it takes this time for a totara to mature. This is ver.y misleading. The Californian redwood in virgin forest lives from thirteen hundred to seventeen hundred and fifty yean, but the most profimble cutting age is somewhere about fifty to eighty years. Douglas fir lives from tour hundred and fifty to seven hundred and fifty years in virgin forest, while in English plantations it is cut at forty years. Sir David Hutchins, writing in 1916, states, "there haa been no scientific forestry in New Zealand, and no foresters to measure the actual production of timber per acre per year in the forest, surely a strange position in a forest country after seventy-six years of civilisation. This same authority states that the indications are pretty clear that the native New Zealand timber trees grow, on an average, decidedly faster than the five chief timber trees in the forests of Europe. Kauri has a somewhat better height growth, and almost double the diameter growth. In a normal dense forest the height growth of kauri would be improved and the diameter growth reduced. There is the remarkable fact that kauri with yearly rings nearly one inch is known. In the common pine of Europe, Scotch pine, apart from deformity, uo such broad rings would ever occur. A kauri planted by Sir Edwin Mitchelson at Dargaville, showed at sixteen years from planting a diameter of nine inches, and a height of thirty-two feet. The rings of growth on New Zealand trees are not so clear as on European trees, but they are generally clear enough to be accurately counted with a little trouble. The only rings not found to be yearly are those of the rewa rewa (Knightia excelsa). The yearly character of all the other rings is judged from the appearance of the rings themselves, and from the check afforded by rings on planted trees of known age. With a few exceptions the ring growths of Sew Zealand trees show an average growth rather faster than European trees, and a good deal faster than South African native trees.

Albinism in Plants and Birds. Mr. L. H. Tomlh-fcon, of Curraa Street, Poneonby, has sent me two cream coloured flowers of prunella vulgaris, commonly known heal, a common herb of the mint family, this plant is destitute of active properties, but was anciently thought to be a panacea. Self heal was first recorded in New Zealand in 1864 and is now one of tka most abundant and widespread naturalised plants in New Zealand, being abundant in both Islands, Stewart Island and the Chathams, and k a very common weed in lawns in Auckland, where it can be readily recognised by its purple flowers. It is a cosmopolitan plant, being found in Europe, North and West Asia, North Africa, and North America. The cream flowers which Mr. Tomlinson sent were collected by him at Hamilton in a locality surrounded by plants bearing the usual purple fowers. There were about a dozen plant*; bearing these cream coloured flowers. Mr. Toirlinson wishes to know if they are of an unusual kind. The cream colouring if due to a form of plant albinism. and the absence of the usual colouring i- due to a lack of pigment, or if present, to its not being developed. Albinism in plant si« g-neraTly a whitish condition, and i» 'lie state of leing an albino, a name originally applied by the Portupup? • to negroes on the coast of Africa who were mottled with white spot-. i>ut is now applied to a person, animal, or plant, detective in colouring pigment. Albini.-:n may be total, but it i? more frequently partial. When total, it implies that the hereditary factor or faet'Or- j,. : pigment production must Ivave dropped out of the inheritance. W hen paitial. it mav mean a general deticienry in the pigment available, or ;n ferments required to give the pigment forming material its coloured expression. Albinism i- not to be comu-e-1 with normal whiteness in whi<-h different pigment factors neutralise <t- another in (,\ pre.—ion. and it 1- no; to be supposed tnat the cold of winter jj, directly :espor.sible for making the new feathers of some birds, for example, the ptarmigan, colourless.

The cold in th» instance acts as a stimulus to a pre-established rhythm; the cold causes vacuoles i' l "'" and take the place of pignie-nt granule-, the whitened being •l"ie to the reflection of the light trim a multitude of interna] surfaces. In me case of the Arctic fox, which only turn? white in winter, the chancre of colour if due to numerous gas vacuoles ill the'hair. and this inot accompanied by • destruction of the pigment, which i® merely concealed by the air-bubbles.