Risk Management: Elements to Consider in Developing Plant Health Policy for Forest Products

Marcell Dawson

The plant health policy developer is primarily functioning as a risk manager. This paper will (i) highlight the elements that risk managers need to consider in developing effective plant health policies; (ii) outline steps involved in the risk management process; and (iii) illustrate examples of current plant health policy considerations relative to the transport of forest products in international trade.

The development of effective plant health policy requires risk managers to (i) work cooperatively within a consultation framework of various experts, namely, technical/scientific, industry, government, and the general public; and (ii) use a risk management process to ensure all essential elements are included and that key decisions are effectively communicated to stakeholders.

The risk management process consists of essentially three stages:

(i) pest risk assessment (PRA);

(ii) identification, evaluation and selection of risk mitigation options (also referred to as the risk management stage); and

(iii) risk communication.

The PRA involves identifying the risks/hazards involved in the transport of specific commodities from one region/country to another, such as pests that are not known to exist in one country and if introduced into that country could become established and cause significant loss or impact to plant resources of the importing country. It is important that the risk manager have a complete PRA with details of pest distributions, pest pathways, probability of establishment and potential economic impacts of pest introduction. In an ideal world, PRAs would be complete and accurate, however, in the real world risk managers must deal with incomplete science to make decisions. They often rely on predictive models or quantitative analysis to make policy decisions.

In the second stage (risk management), risk managers rely, in addition to the scientific information provided in the PRA, to economic assessments, which provide comparative costs of implementing potential policy decisions regarding mitigation options. It is important for the risk manager that as many mitigation options as possible be considered, and that credible scientific studies be provided to support the efficacy of each mitigation option. The cost of proven efficacious options should then be factored against the cost of not implementing proposed measures prior to making a decision. Plant health regulators are advised to follow the International Plant Protection Convention (IPPC) plant health principles when making policy decisions. One of these IPPC principles is “the cost of implementing plant health regulation should not exceed the benefit.” Other elements that must be considered are impacts to trade, and regional and political differences.

Plant health regulation can have both positive and negative consequences. For example, the prohibition or restriction on imported commodities can seriously affect (i) international trade patterns/relations; (ii) economic development in certain commodity sectors; and (iii) increase the cost of certain commodities to customers. On the other hand, the proper application of plant health regulations will help protect a country’s plant resources from devastating pests and diseases, and reduce environmental impacts from exotic pest invasion and future pest management programs which often involve increased use of pesticides to combat pest outbreaks or costly eradication programs involving the destruction of host material. In addition, by providing pest-free areas, countries may benefit from an increase in trade, and lower production and certification costs for certain commodities.

Because of the seriousness of plant health policy decisions, it is essential that policy be developed in an environment of transparent and inclusive communication with all stakeholders, in essence the final stage of risk management is effective risk communication. Effective risk communication begins with formulating a well thought out communication plan. The plan should contain a summary of the supporting science, with references linked to the supporting third party studies and outline the pros and cons of various policy options. Information should be presented in a concise, simple manner so the general public can understand the essential elements. The plan should identify all parties that could be affected by the intended policy decision, “stakeholders.”

Once the communication plan is completed, the risk manager should invite all stakeholders to participate in the decision making process, “consultation.” One method of consultation that I’ve employed successfully is to invite a broad group of stakeholders, ensuring that the likely proponents and opponents to change are invited, to participate in a general information session. Then ask the larger group to nominate/select a smaller working group to represent them in analyzing data and finding solutions, while the larger group continues to be involved in progress reporting meetings. This can be done in various ways, i.e., e-mail distribution list, regular conference call meetings, etc.

Another key aspect of effective communication is ensuring that all parties are equipped with the same essential information, and that each stakeholder group nominate a limited number of media-trained spokespersons who are given up to date information by their working group representative.

The second half of my paper will present information regarding possible pest mitigation options available for forest products. This information, although compiled by a broad group of expert scientists, is still a “work in progress,” and by the time this paper is read will likely be out of date or incomplete.

Pest mitigation begins with good forest management. Keeping pests out of a crop production area or controlling pests at a nondamaging level are good first steps. Selection of healthy timber and culling out weakened stands are other manners of ensuring a low risk of pest presence in forest products. Debarking of logs will eliminate bark beetles and surface pests, including many fungal fruiting bodies. Cutting of the outer portion of the log (sapwood) will remove sapwood pests. In some cases, visual inspection of forest products can be successfully applied to remove certain pests, e.g., boring insects which leave readily identifiable traces such as grub-holes. However, this option is very resource demanding and is likely limited to high quality specialized products, i.e., log houses.

The use of heat through various methods, i.e., kiln drying, steam treatment, hot water bath, and microwave technology, is very effective in killing most pests. Scientific studies have shown that treating wood to ensure a wood core temperature of 56°C for 30 minutes is effective in killing most insects, nematodes and some pathogens. Currently, most countries recognize kiln drying wood to below 20% moisture content as a safe plant health treatment for wood. Some countries require specific wood core temperatures be met to eradicate a specific pest, e.g., the European Union requires conifer wood to be heat treated to a core temperature of 56° for at least 30 min to kill pine wood nematode (Bursaphelencus sp.) and its insect vector (Monochamus sp.). By increasing the core temperature to 71°C for 75 min most pathogens can also be killed, however, by requiring the wood to be heat treated to the higher temperatures, many industries would not be able to economically achieve the higher treatment standard due to unavailability of sufficient cost-effective technology and in some cases, because of unacceptable damage caused to the product due to the higher temperature treatment process. One scientist has concluded that heat pasteurization at 67°C for 60 min will kill most pests of quarantine significance, and this treatment may be economically feasible for some uses. It is important to note that scientific studies conducted in the area of heat treatment have been performed in vitro and have focussed on killing temperatures for various organisms rather than looking at temperatures able to render the organism incapable of reproducing itself in a new host, in nature. It is also important to note that most pathogens require at least 20% moisture content to complete their life cycle. Therefore, a combination of heat treatment to achieve a core temperature of 56 ° for 30 min and drying the wood to a moisture content of 19% or less will greatly reduce the risk of spreading most pathogenic organisms found in wood and could be seen as an acceptable alternative for many forest products. It will also reduce the risk of re-infestation because the kiln drying process permanently alters the cell structure of the wood making it less attractive to secondary pest attacks.

Chemical treatments range from gas fumigation to liquid sprays or dips. The best known of the gas fumigation treatments is methyl bromide. However, studies in the control of wood organisms are limited to select species and pests. Methyl bromide is targeted for phase out due to environmental concerns under the “Montreal protocol.” Other fumigation compounds appear to be less effective than methyl bromide. Overall, the use of gas fumigation is not as effective as heat treatments because there are concerns with penetration of the compound into the wood, and recent evidence suggests that fumigants do not perform well in temperatures below 10°Celsius.

Chemical sprays and dips may be effective for surface treatments but are ineffective in killing pests that reside inside of wood. However, liquid chemical agents used in combination with heat under pressure, “chemical pressure impregnation (CPI)” may be effective against many wood pests. However, few scientific studies exist that show the effectiveness of CPI in killing pests that are present in the wood prior to treatment. This is likely due to the fact that most CPI treatments are used as wood preservatives and aim at keeping the pests out of the wood rather than killing pests that are already present in the wood.

The following examples illustrate current policy decisions relative to the import of forest products from a Canadian perspective:

1) Plant health policy for the import of logs from off continent sources into Canada. Policies were completed based on pest risk assessments that identified the risk of specific temperate species from specific countries. PRAs are conducted in response to importer requests to import specific log species from specific areas. Tropical species are exempt due to Canada having no tropical forests to protect from pests associated with these species. The base treatment for temperate species where a pest risk has been identified requires debarking and heat treatment to a core temperature of 52°C for 30 min for logs. A decision was made by a Canadian scientific and regulatory panel in 1996 that the level of risk presented by this product was one that Canada could live with, given that, debarking removes bark beetles and other surface pests and heat treatment at 52°C for 30 min at the core will kill most wood insects and nematodes and some pathogens (based on Canadian studies for eradication of pine wood nematode and its insect vector, Monochamus). In addition, special import permits may be granted to allow for other treatments or processes. These are reviewed on a case by case basis, e.g., during the winter period logs may be imported into Canada under less restrictive requirements due to the lower risk of pest introduction and spread because of colder ambient temperatures.

2) Plant health policy for solid wood packing material (SWPM). Due to the manner in which wood packing, ie., pallets, crates, skids, and dunnage, are used in moving various cargoes in trade, it is usually impossible to determine the type of wood used or the origin of the wood. Therefore, a PRA was conducted focussing on the pathway rather than on specific pests. However, a broad range of individual pests were selected from recent interceptions in SWPM arriving in Canada with imported cargoes from various regions of the world. The PRA is currently (as of January 2001) in draft format and being reviewed within Canada and it should be available for international review by the time of this conference.

Canada is participating in the development of an international plant health standard for SWPM via the designated IPPC working group. The key components of the proposed standard are baseline treatments (supported by scientific study) to provide an acceptable level of protection from pests associated with SWPM, and an internationally recognized marking system (supported by national plant protection inspection/auditing programs) to provide a visual product certification scheme permitting trace-back of the SWPM to source.

Although some scientists are likely to recommend that the proposed heat treatment of 56°C for 30 min in the draft IPPC “Wood Packing Material Standard” should be raised to 67°C for 60 min or 71°C for 75 min to ensure that a larger range of possible pathogens are killed, but it is my opinion that the proposed heat treatment standard for kiln-dried wood (dried in a kiln to below 20% moisture content) be maintained for practical reasons. Namely, because the current industry practice of kiln drying conifer wood can meet the current standard, whereas raising the bar is not economically feasible at this time. Also, the drying of lumber to below 20% moisture content will reduce the risk of pathogens because most fungi require a moisture content of 20% to complete their development. It is also my opinion that a standard for heat treatment without moisture reduction “heat pasteurization” could be adopted at the higher temperature/time standard and would likely serve as a preferred mitigation option for deciduous SWPM, because hardwoods used in the manufacture of pallets are normally assembled in a green state due to ease of stapling or nailing, and kiln drying costs for hardwoods is expensive and not economically feasible for use as packing wood.

Canadian plant health officials are willing to accept some risk to ensure greater industry compliance to practical solutions via a new international wood packing material standard and are working with industry and scientists to help identify other possible mitigation options.