Bid to protect timber from sap stain, rot

Press, 30 July 1986, Page 11

Bid to protect timber from sap stain, rot

By

OLIVER RIDDELL

in Wellington

Wood preservation scientists at the Forest Research Institute at Rotorua are giving a high priority to finding ways to protect export roundwood and sawn timber from sap stain, mould and rotting. This problem arises because not all the roundwood cut gets to its market quickly. It may be stockpiled in the forest, at the sawmill or on the wharf for long periods, or even on board ship or at the market. Treatments for sap

stain have been used only on sawn timber and give only short-term protection. This is seldom for longer than three months, depending on the climate and storage conditions. Sometimes even treated timber is no longer protected by the time it has reached its destination, and untreated roundwood is even more at risk because it is not being treated at all.

This does nothing to help the image of the New Zealand timber industry overseas — particularly pinus radiata and particularly in Japan. The Japanese have regarded radiata pine as being good for only boxing and packaging.

But there is now a growing interest in the timber for other uses, such as furniture manufacture. Institute scientists are working to improve the condition in which the timber reaches its buyers. Buyers do not want stained timber and will not pay New Zealand good prices until it can deliver the kind of product they want consistently. Research is being done on five fronts:

• Experimenting with higher concentrations of chemicals, to extend the "safe” storage and transit time.

• Developing new antlstain formulaftbns. • Adding repellents to

chemicals so that once the timber is dry it does not get wet again. • Developing new methods of applying treatments. • Developing new loghandling that shaves the bark and cambium layer from the logs, followed by anti-sap stain treatment to reduce fungal decay. The director of the institute’s wood technology division, Mr John Butcher, said a lot of resources were going into the project because there were two possible gains.

First, the timber would then be suitable for the high value end of the market, so prices should rise.

Second, once the image of radiata pine had been raised a lot more of the processing for the Japanese market could be done here in New Zealand, with the approval of the Japanese. He said all the main log exporters had representatives on the small committee helping to guide work, which showed trade interest in the project.