TIMBER AIR-DRIED ON WEST COAST.

Star (Christchurch), Issue 18544, 18 August 1928, Page 2

TIMBER AIR-DRIED ON WEST COAST.

NOT SATISFACTORY FOR USE IN CHRISTCHURCH, DECLARES EXPERT.

Commenting on a statement published recently that timber can be dried satisfactorily on the West Coast, Mr W. G. Morrison, Conservator of State Forests for the Canterbury-Otago region, stated this 'morning that in timber required for use in Christchurch this was incorrect. Timber normally air-dry in Westland would certainly contain more moisture than if it had been normally air-dried timber in Christchurch. The reason was apparent, and could not be disputed. The degree to which timber could be dried depended on the humidity or degree of moisture present in the atmosphere, and, whereas on the West Coast, owing to the prevailing humidity, it was difficult to dry timber below IS per cent moisture content, on the other hand, in Christchurch the weather conditions are such that the timber could often be dried to 12 per cent moisture. Timber, therefore, which would be considered air-dry on the West Coast, and would give excellent service in that locality, would shrink considerably if put into use in Christchurch without allowing it a further seasoning period at the latter place.

The statement that “ timber up-end-ed to rain and weather dries and seasons superior to and quicker than by dry flat strip stacking ” was incorrect, Mr Morrison stated. The flat strip stacking method was the recognised commercial practice of drying tirhber throughout the world. It was also incorrect and unfair to state that sap green timber became brittle on kiln drying and lost its nature. The process of kiln drying was highly technical, however, and it was necessary to control the factors—temperature, humidity and circulation within the kiln—consistent with the moisture content of the timber to be dried. If this was done, sap green timber could be kiln dried just as satisfactorily as air-dry timber. Hit and miss methods of regulating the factors mentioned could, however, quite easily cause serious degrade in the kiln drying of the timber.