19

C—3

Strength tests carried out on green and air-dry material of four species of native and exotic woods, including taraire, pukatea, hinau, and redwood, have advanced the testing programme of the Forest Service to a point where internationally standardized tests have now been made on seventeen species of native and exotic woods. This has made possible the development of strength - specific - gravity laws for local timbers, enabling a very fair approximation of the various strength values of any timber to be made from a knowledge of specific gravity alone. The grading of structural timbers was further advanced by the completion of the testing of structural-sized specimens of rimu and insignis pine, correlating the strength properties with defects occurring. Visible defects are the basis of structural classification. Signal progress was made in wood-preservation studies by the installation of a plant capable of butt-treating full-sized telegraph-poles. The co-operation of the Post and Telegraph Department on this project was secured, with the result that the latter has agreed, to install on service lines treated locally-grown exotic poles. It is anticipated that many sjieeies which would be unsuited for other methods of utilization will be used in this manner. Detailed examinations of the suitability of New Zealand native and exotic species for pulp and paper making on a laboratory scale were completed at the Pulp and Paper Laboratory of the Commonwealth Council for Scientific and Industrial Research. Commercial tests carried out in co-opera-tion with the United States Forest Products Laboratory, Madison, Wisconsin, were also commenced. The Engineer in Forest Products was present at each of these series of tests. While the results are not yet complete, progress reports to hand indicate that the tests are entirely satisfactory. Studies under Way and Investigations. Altogether over thirty major investigations are in progress. These include : Sawmills and wood--waste survey; introduction of shop grades into New Zealand grading rules; wood requirements of wood-using secondary industries ; statistical survey of sawmilling industry ; woods for butter-boxes ; uses for short lengths of timber ; standardization of sizes, grades, and nomenclature for yard timber ; utilization of little-used species ; study of floating properties of New Zealand woods ; physical properties of wood ; air-seasoning of wood ; basic mechanical properties of woods grown in New Zealand ; grading rules and working-stresses for structural timbers ; cross-arm tests ; routine strength tests of plywood ; test of box-bindings ; study of nail-holding power of New Zealand woods ; treatment of wood by non-pressure process ; treatment of wood by pressure process ; service-test records ; routine examination of wood-preservatives ; the pulping of thinnings from Rotorua plantations ; suitability of New Zealand woods for pulp ; microscopic structure of woods ; kauri-bleeding ; relation between durability and the chemical composition of woods ; destructive distillation of native and exotic woods ; relative resistance of untreated woods to borer-attack ; relative resistance of untreated woods to decay ; prevention of the introduction of forest and timber insects and fungi in imported forest products. CHAPTER V.—GENERAL. 1. Report on the Timber Trade. Production. The following table, showing the reported output in feet board measure of the various species of timber from New Zealand sawmills during the years ended 31st March, 1925, J926, and 1927, has been compiled from figures supplied by the Government Statistician.

Reported Production of Sawn Timber by Species.

The sawmill production as reported to the Government Statistician was approximately 307 million feet b.m. for the year ended 31st March, 1927. This represents a decrease of 13-1 per cent., and constitutes the lowest cut since 192-1. The production for the year ended 31st March, 1928, is estimated at 310 million feet b.m.

Species. Feet, B.M. 1925. 1926. Per cent. Feet, B.M. 100-00 353,225,000 Per cent. 1927. Feet, B.M. 300,504,000 Per cent. 100-00 Totals, all species 344,095,000 100-00 Kauri Rimu White-pine Totara Matai Beech Insignis pine Other 22,892,000 .. 194,565,000 66,539,000 .. . 18,507,000 23,392,000 7,439,000 7,706,000 3,055,000 6-66 22,766,000 56-52 195,452,000 19-38 75,635,000 5-38 14,110,000 6-79 26,141,000 2-16 8,701,000 2-24 7,072,000 0-87 3,348,000 6-44 55-35 21-40 4-00 7-40 2-46 2-00 0-95 18,475,000 171,489,000 65,328,000 14,179,000 19,380,000 8,596,000 6,668,000 2,389,000 6-02 55-98 21-30 4-62 6-32 2-80 I 2-18 0-78 6-02 55-98 21-30 4-62 6-32 2-80 2-18 0-78