International Standards For Phytosanitary Measures No. 15 (ISPM 15) is an International Phytosanitary Measure developed by the International Plant Protection Convention (IPPC) that directly addresses the need to treat wood materials of a thickness greater than 6mm, used to ship products between countries. Its main purpose is to prevent the international transport and spread of disease and insects that could negatively affect plants or ecosystems. ISPM 15 affects all wood packaging material (pallets, crates, dunnages, etc.) requiring that they be debarked and then heat treated or fumigated with methyl bromide and stamped or branded, with a mark of compliance. This mark of compliance is colloquially known as the "wheat stamp". Products exempt from the ISPM 15 are made from an alternative material, like paper, plastic or wood panel products (i.e. OSB, hardboard, and plywood).
The Revision of ISPM No. 15 (2009) under Annex 1, requires that wood used to manufacture ISPM 15 compliant Wood Packaging must be made from debarked wood not to be confused with bark free wood. ISPM 15 was updated to adopt the bark restriction regulations proposed by the European Union in 2009. Australia held out for approximately one year with more stringent bark restrictions before conforming July 1, 2010
Wood packaging materials must be debarked prior to being heat treated or fumigated to meet ISPM 15 regulations. The debarking component of the regulation is to prevent the re-infestation of insects while lumber is sitting to be manufactured, or even after it has been manufactured. The official definition for debarked lumber according to the ISPM 15 Revision (2009) is:
"Irrespective of the type of treatment applied, wood packaging material must be made of debarked wood. For this standard, any number of visually separate and clearly distinct small pieces of bark may remain if they are: - less than 3 cm in width (regardless of the length) or - greater than 3 cm in width, with the total surface area of an individual piece of bark less than 50 square cm."
What are the post treatment levels of infestation (with and without bark) compared with pre-treatment levels? Overall, from the studies presented there is either: a) no significant difference between infestation levels of treated and untreated wood; or b) differences identified are related to the species of insect which may prefer treated or untreated wood. Supporting information from a North American study (IFQRG 2005-27) is summarised in the Table below (Data are numbers of beetles per cm2):