Imported timber has been a persistent biosecurity concern. Wood pests can survive long international journeys, hide in containers and pallets, and establish in destination forests if they evade inspection. The list of priority threats evolves as international trade patterns shift and as previously contained pests expand their ranges.

The persistent threats

Several pest categories have been priority concerns for years and remain so:

Pine wilt nematode. Carried by various beetle vectors, pine wilt nematode has caused significant pine mortality in Asian and parts of European forests. Risk pathway is primarily through pine and fir wood products and packaging materials. Inspection regimes treat pine wood imports with heightened scrutiny.

Asian longhorn beetle. Established in parts of North America and Europe. Risk pathway is wood packaging, specifically pallets and dunnage, made from infested wood. International standards (ISPM 15) address this but compliance varies.

Emerald ash borer. Has caused devastating ash decline in North America. Risk to Australian ash species is uncertain but precaution dictates continued vigilance. Pathway primarily through ash wood products.

Various bark and ambrosia beetles. Multiple species in various source countries, often co-occurring with fungal symbionts that compound damage. The list of concerning species is long and updated regularly.

The emerging threats

Several pests have gained increased attention in recent years:

Polyphagous shot-hole borer. A small ambrosia beetle that has caused significant urban and forest tree damage in California, Israel, and South Africa. Risk pathway is wood products, but the beetle has hosts across many tree species. Established in Western Australia in some contexts. Containment is difficult.

Spotted lanternfly. While not specifically a timber pest, its wide host range includes many tree species and its movement is associated with various wood products and shipping pathways. Awareness has grown significantly in 2025-2026.

Pine processionary caterpillar. Significant pine forest pest in Mediterranean Europe with potential spread routes. Climate change is expanding its range. Inspection of European pine imports has increased focus on this species.

Various Phytophthora species. Soil-borne pathogens affecting forests globally. While not strictly timber pests, they spread through nursery stock, soil contamination, and plant materials. The list of pathogens of concern continues to expand.

How risks are changing

Several trends affect the timber pest risk picture:

Climate change is shifting pest ranges. Pests that were previously limited by climate are expanding. This affects both source country pest pressure and the risk that incoming pests find favorable conditions in Australian forests.

Trade pattern shifts change risk profiles. As trading partners change, the species and conditions of risk change. Increased trade with previously minor partners brings new pest exposure profiles.

Wood processing and packaging changes. As wood packaging is replaced with alternative materials in some contexts, the risk pathway shifts but doesn’t disappear. Wood-substitute materials sometimes have their own biosecurity concerns.

International standards evolution. ISPM 15 compliance for wood packaging has improved over years but isn’t universal. Some emerging pests aren’t fully addressed by current standard treatments.

What inspections focus on

Frontline timber import inspection focuses on:

• Visible signs of insect damage (holes, frass, gallery patterns)
• Suspect wood condition (still green wood, presence of bark, treatment markings)
• Compliance with ISPM 15 for wood packaging
• Documentation of treatment regimes for high-value imports
• Random sampling for laboratory analysis when warranted

The 80/20 rule applies — most imports are uneventful, a small percentage require detailed attention, and a very small percentage are genuine biosecurity issues. The challenge is identifying which is which efficiently at high volume.

What importers should do

For importers of timber and timber products:

Source from compliant suppliers. ISPM 15 compliance, treatment certifications, and pest risk documentation should be standard. Suppliers without strong biosecurity practices create problems for importers.

Document treatment regimes thoroughly. When biosecurity questions arise, good documentation enables fast resolution. Poor documentation extends inspection time and creates costs.

Plan for delays in high-risk categories. Pine, hardwood from regions with active pest concerns, and bulk timber imports all involve longer inspection times than alternatives. Procurement timelines need to account for this.

Engage with industry consultation. Biosecurity rules evolve. Industry input matters. Importer associations and individual companies that engage with consultative processes get better outcomes than those who don’t.

Report concerns proactively. Importers who identify potential issues in their supply chain and report them get treated very differently than importers who try to push through and get caught later. The system rewards transparency.

What forest managers should watch

For forest managers and land managers:

• Monitor for unusual tree decline or unusual insect activity
• Report unusual findings promptly through official channels
• Participate in surveillance programs where available
• Stay informed about pest threats relevant to your forest type
• Consider biosecurity implications in management decisions (movement of equipment, timing of operations)

Early detection is the strongest tool against established incursions. The pests that cause the most damage are usually the ones that were detected late or not at all.

The longer-term picture

Timber pest risk is unlikely to decrease in the next decade. The combination of trade volume growth, climate change, and continued pest expansion globally points toward more rather than less pressure on biosecurity systems.

The systems that work well share characteristics:

• Risk-based inspection that prioritizes attention where threats are highest
• Strong international coordination on pest risk information
• Active surveillance domestically to catch incursions early
• Industry partnerships that align commercial and biosecurity interests
• Continued investment in detection technology and trained inspectors

Australia’s biosecurity system has these characteristics in reasonable measure. It’s not perfect — no system is. It’s better than many comparable systems. Maintaining and improving it requires continued investment and political support.

For practitioners, the practical work is the daily work — careful inspection, good documentation, prompt reporting of concerns, and continuous learning about evolving threats. That work, done well across thousands of touchpoints, produces the system-level outcomes the country depends on. The investment in that work matters more than the technology or policy that gets the headlines.