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，加拿大木制品或木质包装产品向国外市场的出口将受到限制。通过对流加热和甲基溴熏蒸等处理，可维持受感染地区木制品的出口。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被逐步淘汰。热处理并不总是经济可行的，特别是对于较大尺寸的材料；对于出口的含湿量高的绿色木制品来说，这是不切实际的。其他处理方法包括其他熏蒸剂、化学加压浸渍、微波或射频技术的电介质加热和伽马辐射。在绿色木材产品的替代方法能够在工业上使用之前，它们需要进一步开发和优化，然后得到国际植物检疫控制组织的批准。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认为是木材的一种干燥过程，但它还没有被测试用于消除绿色木材中的害虫。这可能是一种在短时间内引入高温（例如70摄氏度2分钟）的有效方法，这将导致保持更多的水分进入木材。如果成功，该技术可以迅速在工业规模上实施，可以改变大型绿色尺寸木材和原木的国际贸易中处理虫害控制的方式，并将使加拿大工业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.