Many types of woods can be susceptible to mold. Most people are concerned about mold in their homes. Mold can grow on cloth, carpets, tiles and wood. Shippers and packagers of products are also concerned about mold and its affect on the packaged product or whether mold on a wood package will cause the container to be rejected at customs. It is understandable that people are concerned when they see mold, but many of the issues believed to be associated with mold are not true.
Mold is not restricted by ISPM 15; there are no international laws nor are there any countries that may reject a wooden crate that has mold, as long as it has an ISPM stamp. ISPM 15 addresses invasive insects that bore inside of wood. Once transported to another geographical region, the “foreign species” can wreak havoc on the environment as the invasive insect may not have any natural enemies in new country. We have discussed the Asian Longhorn Beetle as an example of an insect that came from China via wood packaging and is now infesting and killing a number of trees in the US.
Here are some reasons that ISPM 15 would not concern itself with mold:
- Mold is found everywhere in the world it is part of the natural environment, it helps break down dead organic matter such as leaves and fallen branches. Technically, although there are a number of different kinds of mold, it is not an invasive species.
- Mold does not affect the structural integrity of wood, it grows on the surface. Mold can be easily wiped off.
- Mold does not kill living trees, nor does mold hop from one tree to another. Introducing mold into a region will not cause mold infestation.
Heat treatment will kill any mold that is present on the wood, but it will not prevent future contamination from mold. Mold will grow on wood in the presence of warm temperatures, high humidity and lack of UV radiation (sunlight). These conditions are hard to control in any lumber yard in the summer time, especially with the amount of rain that the Midwest has received in 2014.
Some people believe that mold will cause wood to rot, this is not true. Mold in the house is an indication of moisture problems, so while the surface mold may not be harmful, long term moisture problems can cause wood rot. For this reason mold is associated with wood rot, but mold does not cause wood rot. A different type of fungi called “wood decay fungi” causes wood rot, but needs significantly more moisture to thrive.
There is another type of fungus called “Blue Stain” that is not mold, but sometimes is mistakenly referred to as mold. Blue stain is a fungus that attacks the natural sugars located in the sapwood of softwood lumber species. It is characterized by a blue or black stain. While mold can be easily rubbed off, blue stain is embedded in the wood fiber. Blue stain is prevalent in Canada and the US and is generally spread from tree to tree by wood boring beetles. Blue stain does not affect the structural integrity of wood. ISPM 15 does not restrict blue stain wood; however there are some countries (notably Australia and China) that may reject wood crates that contain blue stain fungus.
Packnet does try to prevent or minimize mold on wood during summer months by keeping lumber dry as possible and allowing more airflow by unwrapping bundles. Mold may be undesirable but it is still compliant to ISPM 15 Standards so long as it has been heat treated or fumigated per the requirements.