What is heat treated wood?

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Whether you realise it or not, you probably have been affected by heat-treated wood today. Heat-treated wood is widely used in the manufacture of packing crates, which are used in the overseas transport of many imported and exported goods that we use every day.

Since many customs programs will turn away any wooden packaging that is not heat-treated, there's a good chance you have recently handled a product that was shipped in heat-treated wood.

Wood Packaging

Nearly all goods that are transported overseas by boat or plane are packaged in wooden crates, and these crates are often required by law to be constructed of heat-treated wood. Because insect pests can live in raw (untreated) wood, wood used in the manufacture of shipping crates must be heat treated to destroy any pests living inside.

Heat Treatment

In order for wood to be certified as heat treated, the wood must have been heated to a temperature of at least 56.1 degrees C (13.3 degrees C C) for at least 30 minutes. This temperature and duration is considered adequate to destroy any itinerant pests in the wood. Methods of heat treatment include kiln drying and chemical pressure impregnation (including steam heating, hot water heating and dry heating).


For customs purposes, heat-treated wood must be certified with certain types of permanent markings. These markings must be present on at least two sides of the wooden article. The markings include: the IPPC symbol (the symbol for the International Plant Protection Convention), the internationally recognised code for the country of origin, a unique number designating the producer of the wood and an indication of the person or body responsible for the use of the correct wood and marking procedures for that wooden item.


Heat treatment is an effort to prevent the introduction of non-native pest species into native ecosystems. Many countries, including the United States, have experienced outbreaks of non-native pest species. Non-native pest species that live in wood can threaten native forest ecosystems, since a natural predator will often not exist for an introduced pest species. Common pest species include the confused flour beetle, the red flour beetle, the warehouse beetle, the saw-toothed grain beetle and the Indian meal moth.

  • Heat treatment is an effort to prevent the introduction of non-native pest species into native ecosystems.

Rules and Consequences

In the United States, a wooden crate or packaging material can be considered noncompliant with heat treatment rules under three categories: unmarked, inappropriately marked or infested. If a packaging material is found to be in violation of heat treatment rules under any of these categories, the material can be subject to re-export at the cost of the importer. Additional financial penalties can also result from the use of wood that is not compliant with heat treatment rules.