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57. In order to examine possible means of improving the staple-holding powers of creosoted-pine posts, tests were carried out on untreated totara, creosoted larch, creosoted Douglas fir, and creosoted Corsican pine, using both barb and shear staples. There waa not much to choose between the staple-holding powers of untreated totara, creosoted larch, or creosoted Douglas fir. The staple-holding powers of Corsican pine were somewhat inferior, but this difference was minimized by increasing the length of the staple by \ in. Barb staples were found to have poorer holding-powers. 58. With the experimental pressure-impregnation plant suitable treatment schedules for the preservative treatment of larch, Corsican-pine, and Douglas-fir poles have been determined, while considerable work has been done on the preservative treatment of insignis-pine sleepers. The conditioning of green timber in the pressure-cylinder so that it can be impregnated without prior drying has been examined, but minor alterations to the plant will be necessary before further tests can be undertaken. 59. Service testing of creosoted rimu and larch poles, and insignis-pine sleepers, in co-operation with other Government Departments, was continued. Additional specimens have been installed in " graveyards " maintained by the Forest Service for the testing of wood-preservatives, and arrangements have been made to test the natural durability of several New Zealand timber species in co-operation with overseas laboratories. The tests have been designed so that it will be possible to compare the natural durability of New Zealand timbers with the natural durability of some of the better-known species of other countries. 60. The testing of wood-preservatives against marine-borer infestation in co-operation with the Auckland Harbour Board has been in progress for some time. After seven vears' exposure, specimens of exotic softwoods, including insignis pine, treated with coal-tar creosote in accordance with recommended practice for marine piling, are free from attack. Similar test specimens, pressure impregnated with a group of woodpreservatives which have shown promising results in overseas tests for this class of work, are now being treated for exposure in Auckland Harbour. 61. The wood-preservation section continued to deal with many requests for assistance or technical advice from the industry, the public, and from Government Departments. Information on methods of sap stain prevention, borer control, methods of formulating toxic chemicals in organic solvents, and general wood-preservation requirements was frequently sought. CHAPTER VI—COMMERCIAL DIVISION Inspector in Charge : Mr. W. C. Ward Log-production 1. General. —Despite various difficulties the production of logs from departmental! logging operations created a new record. Labour was continually short and at times new equipment was unobtainable. Nevertheless, the total log deliveries represented 9 per cent, of all log supplies to the sawmilling and the plywood industries. Activity was concentrated mainly in the North Island where 7 per cent, of the log input of indigenous species and 15 per cent, of the exotic species required by the major industries were provided. The Forest Service filled all contractual requirements. 2. To ensure that the forest-owner obtains the maximum return for his forest and the sawmiller receives a constant supply of reasonably-priced sawlogs it is necessary that the logging operations in any particular forest should be conducted at a level which will provide for the maximnm economic use of logging equipment. It has been found that when one logging operation is conducted for the supply to a group of normal indigenous sawmills that a more efficient use of equipment and man-power can be obtained and at the same time the sawmills are provided with better log supply than they could obtain

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