The pallet to firewood pest connection

At least 58 non-native wood-boring insect species have been detected in the United States since 1985; nearly all are suspected of having entered the country in crates, pallets, or other forms of packaging made of wood. And despite the far tighter regulations on wooden packaging that were put in place in 2006, some wood boring insects are bound to continue sneaking into North America.

Since these insects live deep inside wood, they are difficult for people to detect. This means that importers and shipping companies have a tough time seeing if wood is contaminated, and just about anyone could unknowingly spread these pests within contaminated firewood.

Two examples of the severe harm that this sort of pest can wreak are the Asian longhorned beetle and emerald ash borer. The Asian longhorned beetle (ALB) has been introduced to North America and Europe more than a dozen times via contaminated wood packaging from China. Most of these outbreaks were not discovered for many years – because even though this is a large insect, it spends most of the year hidden inside the heart of the tree.

The U.S., Canadian, and European governments have spent close to $600 million dollars- and removed nearly 100,000 trees- in order to eradicate these outbreaks. Thankfully, these programs are succeeding: as of this writing, four of the seven North American ALB populations have been eradicated: Chicago IL; Long Island NY; Hudson County NJ; and Toronto, Canada.

But three outbreaks remain – a fairly isolated infestation within New York City, the large infestation in Worcester, Massachusetts, and the newest found ALB infestation in Clermont County, Ohio. The infestations in Massachusetts and Ohio will be difficult to eradicate, but history has shown that it is possible if given the proper time and resources.

The emerald ash borer apparently entered North America only once, according to genetic evidence and scientific analysis of infested trees . However, it has spread rapidly to an area of almost 200,000 square miles in 19 states. So far, EAB has killed more than 50 million trees. After spending more than $300 million over 10 years, the U.S. and Canadian governments now leave efforts to states, cities, and homeowners. Towns and homeowners are now responsible for the costly (estimated at $1.2 billion per year) removal of dead and dying ash trees before they fall over, damage property, or injure people.

It can feel so disheartening to read about these problems, but there are several concrete things that anyone can do that will really help.

  • Don’t move firewood- use only local or heat treated firewood when you go camping or traveling.
  • Tell your friends, your coworkers, and your family about the issue of contaminated firewood.
  • Educate yourself on how to spot the symptoms of pest infestations. Learn about ALB exit holes, take a look at this picture of a nearly dead ash tree with strange leafy sprouts near the base of the trunk (caused by EAB damage), and look around for excessive or strange looking woodpecker damage on individual trees.
  • If you see a sickly or dying tree that you suspect might be infested by pests, report it to your state agricultural, natural resources, or forestry agency. Quick reporting can make the difference between a small infestation that is controlled quickly, or a huge infestation that causes the deaths of thousands of trees.

Preventing pest entry on plants

We’ve talked a lot here on Don’t Move Firewood about how forest pests can enter North America on or in the wood of packaging materials, such as pallets. One thing that we talk less about is that many pests also have reached our shores on imports of living plants. Examples of this problem include the hemlock woolly adelgid, winter moth, and the pathogen sudden oak death.


Until recently, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has tried to prevent new introductions by physically inspecting plant shipments. However, finding pests is very difficult because pests can be tiny, non-symptomatic at the time of import, or just simply very well hidden inside the plant. And of course it is unrealistic to inspect anything more than a minute percentage of total imports.


Protecting our forests and other natural resources for pests demands a more effective approach.


Recognizing this need, APHIS recently created a “limbo” category, known by its lengthy acronym NAPPRA (Not Authorized Pending Pest Risk Analysis). When certain types of plants from specific countries are deemed likely to harbor a particular pest, APHIS can temporarily prohibit imports of these plants via NAPPRA while it analyzes the pest risk and adopts safeguards to ensure that imported plants will be as pest-free as possible.


Last week, APHIS took the first action under this new authority by listing 107 plant genera which are likely to transport one of 13 types of pests. For example, imports of birches, dogwoods, poplars, willows, and 70 other genera of trees and shrubs from Europe and much of Asia are prohibited because they could introduce to the U.S. the citrus longhorned beetle – a close relative of the Asian longhorned beetle (ALB). Citrus longhorned beetles are able to attack an even greater variety of trees than the ALB. Both these large beetles spend months deep inside trees as larvae and thus are very difficult to discover via inspections.


Of course, many of the pests being prevented by these new actions could, if established, travel on contaminated firewood. Here at Don’t Move Firewood we are excited that APHIS has begun applying their new NAPPRA authority to protect our forests. Exciting times!


The Asian gypsy moth problem

The Asian gypsy moth attacks many hardwood or deciduous trees as well as several conifers, including Douglas fir, hemlock, larch, pine, and spruce. Since the female Asian gypsy moths can fly – unlike the European gypsy moth already widespread in the Northeast USA– it spreads more rapidly.

Asian gypsy moths are found in the Russian Far East, China, Korea, and Japan. Like all moths, they are attracted to lights – including lights at ports where ships are loaded. The females then lay their eggs on the ships.

To protect our forests, U.S. and Canadian customs agencies inspect ships coming from northern Asia; ships found with moth eggs attached to the ship or its cargo must return to the open sea and clean off the eggs. Inspecting the ships is difficult, time-consuming, dangerous – and not always a perfect process – which leaves our forests vulnerable.

The U.S., Canada, and Mexico have adopted a regional standard that makes China, Korea, and Japan responsible for ensuring that the ships travelling to North America are not carrying gypsy moth eggs. They must inspect the ships, monitor moth populations in ports and nearby forests, and take other actions to reduce the likelihood of moths laying eggs on the ships. For example, moths are not attracted to lights of a certain wavelength, so using those specific types of lighting reduces the risk while allowing port operations to continue.

This program was applied to Russia in the mid-1990s. It has worked: few ships from Russia now carry gypsy moth eggs.

China, Korea, and Japan are now gearing up their programs – but improvement is needed. In 2012, 31 ships with egg masses were detected by U.S. Customs and Border Protection and required to leave port until they could pass inspection.

Given how difficult it is to inspect ships, it would be easy for some egg masses to escape detection and hatch – starting another outbreak in North America. If it gets established, the Asian gypsy moth could easily be transported on firewood, just like the European gypsy moth. Remember – even if a pest outbreak has not been officially detected, the risk is still present.