99 Percent Invisible: Wooden Pallets Carry Environmental Costs Along with Their Loads
Logging, invasive insects are the problem
Consider for a moment the humble wood pallet. It is so ubiquitous that it’s all but invisible. It is so plainly constructed – of raw wood and nails – that most people never give it a second glance.
Yet the wood pallet is one of the workhorses of our global economy, a key part of the system that moves just about every product you touch. Combined with a hydraulic forklift, the wood pallet is the essential platform for transporting goods from warehouses to store shelves.
Given the wood pallet’s universality, it shouldn’t be surprising that the pallet carries with it a significant environmental burden. For starters, there is the pallet’s incredible use of forest resources. And once put into service, pallets and shipping containers can change the ecological balance of entire continents. Despite the best intentions – and possibly the worst negligence or deceit of companies– they are responsible for transporting invasive insects that are destroying entire tree species in North America, causing billions of dollars' worth of damage to the environment.
A staggering quantity of timber is converted into pallets. According to Hardwood Market Reports, wooden pallets – along with wooden shipping containers – consume 44 percent of all the hardwood produced in the US annually, up from 35 percent 13 years ago. In 2012 about 450 million pallets – each using about 15 board feet of lumber – were manufactured in the United States, says Philip Araman, a leading forest products researcher for the US Forest Service.
Now, it’s important to understand that the logging industry isn’t cutting down trees just to make pallets. Pallet wood is worth about one-tenth the value of high-quality veneer wood, Araman says. The most valuable hardwood trees – one that are straight, tall and have few knots –would be cut down anyway. The best wood from those trees is used for furniture and cabinets; the leftover, inferior wood becomes pallet material. Still, many of smaller, spindly trees that are cut down in a clear cut operation are, in fact, cut down specifically to become pallets or converted to pulp or other engineered wood products, such as particleboard.
So, would our forests be better off we stopped churning out wooden pallets? Depends who you ask. The US Forest Service insists that the level of logging is sustainable. According to its Forest Inventory and Analysis, the number of trees in US forests increases by about 3 percent each year, while about 2 percent of trees are removed, for a net growth in the number of trees.This growth is reflected in the EPA Inventory of Greenhouse Gas Emissions and Sinks, which reports that the amount of carbon dioxide offset by US forests has increased during the past 20 years due to forest regeneration.
Yet the impact of pallets on local ecological systems varies from place to place. Some forests are managed better than others. Poor forest management practices reduce biodiversity and degrade wildlife habitat. “The quality of forest management drives the level of restoration or destruction in the forested environment,” says Brad Kahn of the Forest Stewardship Council, which sets standards and certifies forests that are responsibly managed.
In general, less demand for wood products would require less of a need to cut down trees. If pallets were repaired and re-used more efficiently, some deforestation would be avoided. The good news is that the shipping and warehouse industries are making strides in pallet re-use. The Forest Service’s Araman estimates that nearlyhalf of all pallets purchased have been repaired and recycled. The pallet industry also promotes “pooling” as a cost-saving way to reduce the need for new pallets: companies can rent pallets that are eventually returned to a central location to be repaired and reused. Think of it as the corporate version of the sharing economy.
While the pallet industry and retailers try to re-use more pallets, the pallet carries another environmental risk: invasive insects. Invasive insects’ ecological damage taken can't be overstated. Among the most infamous of these invasive pests are the Asian longhorned beetle, the emerald ash borer, and the redbay ambrosia beetle. “In the last 20 years we've found numerous highly damaging pests that have come in on crates, pallets and wood packaging,” says Faith Campbell, senior policy representative for The Nature Conservancy.
“As near as anyone can tell, the emerald ash borer is going to kill nearly all the ashes in North America – that's 16 or 17 species.”
This chronic problem is closely tied in with the workings of the global economy. As we ceaselessly move goods around the world, tiny hitchhikers often hop a ride on the wood pallets. The redbay ambrosia beetle, which was reported first in Savannah, Georgia, has now spread to five other states, including Florida, where it is infecting avocado trees with laurel wilt fungus. The Asian longhorned beetle, known for killing maple trees, is also destroying hardwood trees in 15 different families. “The alarming thing about the Asian longhorned beetle is that it keeps showing up in wood packaging, even though we thought we had eradicated the outbreak,” Campbell says.
There are procedures in place to try to stop the spread of these invasives, but they aren’t always effective. Before pallets or other wood packaging materials can be OK'd for international use, they must be treated to kill any insects that may be on the surface or imbedded in the wood. The International Plant Protection Convention (IPPC) requires pallets that will cross national borders to be either heat treated (130 degrees F. for 30 minutes) or fumigated with methyl bromide, then marked with the IPPC logo, indicating the type of treatment. (In addition to being toxic, methyl bromide is a significant ozone depleting substance that mostly has been phased out of use by the Montreal Protocol. It continues being sprayed on pallets and wooden packaging under a critical use exemption.)
How do the insects survive the heat treatment or pesticide? Campbell says the insects haven't developed any new resistance: The fault lies with the companies that are supposed to be complying with international law. Some of the breaches are unintentional – the result of faulty fumigation or uneven heating of the wood. But Campbell says she has also seen forgeries of the required stamps on crates, proving that some pallet manufacturers are cutting corners.
Once an invasive insect lands in North America, it has an easy time moving from state to state. Pallets that travel within the United States are not required to be heat treated or fumigated. “There's no reason to think US-made packaging doesn’t have pests in it,” Campbell says.
Government officials at one time considered requiring all pallets in the US to be treated, even if they were just being used domestically, but the idea never gained traction. The Nature Conservancy’s Campbell, who is part of the Continental Dialogue of Non-Native Forest Insect Pests and Diseases, pins her hopes on a combination of technology and education. Personally, she would like to see the industry shift from unprocessed wood to what’s called “oriented strand wood.” Consisting of long strands of wood held together with synthetic resin, OSB resists wood-boring insects. Its main drawback is that it would be extremely difficult to get an international agreement because of the increased costs. In the meantime, education can help. Government officials in Canada, the US and Mexico are trying to arrange workshops with counterparts in China and other Asian nations to reduce the movement of insects across borders.
Plastic pallets are another option that could stop invasive insects and possibly shrink the ecological footprint of wooden pallets. Insects can't bore into them, so they don't require any fumigation; their lighter weight reduces the use of fossil fuel; and they can be manufactured from recycled plastic. However, their higher initial costs has limited their penetration of the pallet market to about 5 percent. All of which means that, at least for the foreseeable future, the environmental problems associated with wood pallets will likely persist.