Assessment and optimization of radio frequency heating technology as treatment to protect Canadian green log and timber exports by killing microbes and other pests

如果加拿大和外国监管机构认为存在植物检疫风险，即木材中存在甲虫/真菌伴生物和其他害虫的风险，则将限制加拿大木制品或木质包装产品向外国市场的出口。虫害地区的木材产品出口可以通过对流加热和甲基溴熏蒸等处理来维持。根据《蒙特利尔议定书》，甲基溴作为一种消耗臭氧层的化学品正在逐步淘汰。热处理在经济上并不总是可行的，特别是对于较大尺寸的材料;对于绿色木材产品，出口的含水量高，这是不切实际的。替代处理方法包括其他熏蒸剂、化学压力浸渍、微波或射频技术介电加热以及伽马辐照。在替代方法可以工业化用于绿色木材产品之前，需要进一步开发和优化，然后得到国际植物检疫控制小组的批准。我们建议评估射频技术作为绿色木材产品的替代处理方法。虽然这项技术已经被公认为木材的干燥工艺，但它还没有被测试用于消除绿色尺寸木材中的害虫。这可能是一种有效的方法，可以在短时间内引入高温（例如70 ℃持续2分钟），从而使木材保持更多的水分。如果成功，该技术可以在工业规模上迅速实施，可能会改变大型绿色尺寸木材和原木国际贸易中害虫控制的处理方式，并将使加拿大工业界有机会成为该技术的领导者，同时保持和增加绿色木材产品的出口销售。

The export to foreign markets of Canadian wood products or products with wood packaging will be restricted if Canadian and foreign regulatory agencies believe there is a phytosanitary risk, i.e. a risk that beetles/fungal associates and other pests are present in the wood. Exports of wood products from infested regions can be maintained by treatments like convective heating and fumigation with methyl bromide. Methyl bromide is being phased out under the Montreal Protocol as an ozone-depleting chemical. Heat treatment is not always economically feasible, especially for larger size material; for green wood products, which are exported with high moisture contents, it is impractical. Alternative treatments include other fumigants, chemical pressure impregnation, dielectric heating with microwave or radio frequency technology, and gamma irradiation. Before alternative methods can be used industrially for green wood products, they need to be further developed and optimized, and then approved by international phytosanitary control groups. We propose to evaluate radio frequency technology as an alternative treatment method for green wood products. Although this technology has already been recognized as a drying process for lumber, it has not been tested for eliminating pests in green dimensional wood. It may be an efficient way of introducing high temperatures for short times (e.g. 70oC for 2 minutes) that will result in keeping more moisture into the wood. If successful, the technology could be implemented rapidly at an industrial scale, could change how pest control is handled in international trade for large green dimensional timber and logs, and would give Canadian industry the opportunity to be a leader in this technology while maintaining and increasing export sales of green wood products.