When a new forest pest arrives in Australia, the immediate concern is ecological: what damage will it do to our forests? But the economic impacts are often even more dramatic, and they ripple through the timber industry, export markets, and regional economies in ways that aren’t always obvious.

Let’s talk about what these incursions actually cost and why the forestry sector spends so much on biosecurity.

Direct Timber Losses

The most visible cost is direct damage to commercial plantations and native forests. When pests establish, they reduce growth rates, kill trees, and lower timber quality.

The sirex woodwasp, first detected in Tasmania in the 1950s, provides a sobering example. Before effective biological control was established, it killed millions of pine trees across Australia. Even now, with sirex under reasonable management, it still causes ongoing losses estimated at $5-10 million annually in reduced growth and the cost of biological control programs.

That’s for a pest we’ve had for 70 years and learned to manage. New arrivals can be far worse before control methods are developed.

When the red imported fire ant was found in Queensland in 2001 (though not primarily a forest pest, it impacts forestry operations), the National Red Imported Fire Ant Eradication Program has cost over $600 million to date. And it’s still not eradicated.

The Export Market Impact

Australia exports around $2.5 billion worth of wood and wood products annually. Access to international markets depends on maintaining our pest-free status for key species.

When a new pest is detected, export markets react quickly. Countries that import Australian timber and wood products want assurances that they’re not also importing pests. This can mean new phytosanitary requirements, additional treatments, or in the worst case, temporary export restrictions.

After the brown marmorated stink bug was found in Australia (it’s a polyphagous pest that can affect many plant species including trees), several trading partners immediately tightened import requirements for Australian goods. The compliance costs alone ran into tens of millions of dollars.

For timber exporters, these market disruptions are potentially more damaging than the pest itself. A sawmill might have contracts to supply timber to Japan or China. If new treatment requirements make those contracts unprofitable or the country temporarily bans imports from affected regions, that’s immediate revenue loss.

The Australian Forest Products Association estimates that each significant pest incursion creates $20-50 million in export market disruption costs through additional treatments, certification requirements, and lost contracts.

Eradication Costs

When a new forest pest is detected early, there’s often an attempt at eradication. These programs are expensive.

They involve intensive surveillance to map the extent of the incursion, destruction of infested material, treatment programs, and ongoing monitoring to verify success. You need entomologists, field crews, laboratory analysis, and coordination across multiple agencies.

The Asian gypsy moth incursions in various Australian ports over the years have each triggered eradication responses costing hundreds of thousands to millions of dollars. Most have been successful, preventing establishment of a pest that could devastate eucalypt forests. But success isn’t cheap.

Even when eradication attempts fail and the pest establishes permanently, you’ve still spent the eradication money. That’s sunk cost on top of the ongoing management costs you’ll now face forever.

Long-Term Management Costs

For pests that establish permanently, there are perpetual management costs.

Biological control programs for sirex, for example, require ongoing monitoring and releases of parasitoid wasps. The network of traps, the laboratory facilities for rearing control agents, the field staff to maintain the program—these costs continue year after year.

Some pests require ongoing treatments. If there’s no effective biological control, commercial plantations might need regular applications of insecticides or other interventions. These costs get built into the cost structure of Australian forestry and make our timber less competitive against countries without the same pest pressures.

The Centre for Invasive Species Solutions estimated in 2025 that Australian forestry spends approximately $85 million annually on established pest management. This doesn’t include research into new control methods or surveillance for new arrivals—just managing the pests we already have.

Opportunity Costs

There’s also what economists call opportunity costs—the things you can’t do because resources are tied up managing pests.

Research funding spent on pest management is funding not spent on genetics, silviculture improvements, or market development. Field staff time spent on pest surveillance is time not spent on other forestry operations. Land that’s lost productivity due to pest damage produces less timber and less revenue.

Some areas have become uneconomical for forestry due to pest pressure. Regions where multiple pests overlap, creating compounding damage, sometimes get removed from production entirely. That’s plantation land that could have been producing timber indefinitely but instead reverts to lower-value uses.

Regional Economic Impacts

In regional areas where forestry is a major employer, pest incursions can devastate local economies.

Sawmills close when timber supply drops. Transport companies lose contracts. Forestry workers lose jobs. The flow-on effects touch retail, services, and other businesses that depend on the forestry sector.

After significant pest impacts in parts of Victoria’s plantation estate in the early 2000s, several small mills closed permanently. The towns they operated in never fully recovered the employment and economic activity those mills represented.

Research by the Regional Australia Institute found that forestry-dependent communities typically experience an economic multiplier of about 1.8—meaning every dollar of forestry revenue generates $1.80 in total regional economic activity. When pest damage reduces forestry output, that multiplier works in reverse.

The Insurance Model

Given these costs, forestry biosecurity is essentially insurance. You spend money on surveillance, risk mitigation, and preparedness to avoid much larger costs from pest incursions.

The tricky part is that it’s hard to measure success. If we spend $10 million on biosecurity and no new pests establish, did we waste $10 million or prevent $100 million in losses? It’s impossible to know for certain what incursions were prevented.

This creates a political challenge. Funding for surveillance and prevention competes with other priorities, and it’s harder to justify spending money on threats that might never materialise than on immediate visible problems.

But the maths is pretty clear. According to analysis by the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES), every dollar spent on forestry biosecurity returns approximately $4-5 in avoided costs. That’s a good investment by any standard.

Quantifying Risk

Modern forestry biosecurity increasingly uses risk assessment models to prioritise threats and allocate resources efficiently.

These models consider factors like:

• Likelihood of arrival (which pests are common in our trading partners, volume of imports from affected areas, interception records)
• Likelihood of establishment (climate matching, host availability)
• Potential impact (host range, damage severity, existing control options)

By multiplying these factors, you get a risk score that helps decide where to focus effort. A pest that’s highly likely to arrive but would have minimal impact gets less attention than one that’s moderately likely to arrive but would be catastrophic if it established.

The Australian Forest Biosecurity Strategy, developed by Plant Health Australia in collaboration with industry and government, uses this approach to identify priority pests and allocate surveillance resources.

What’s It Worth?

So what’s the total economic cost of forest pests in Australia? It’s hard to calculate precisely because impacts range from obvious (timber losses) to subtle (reduced growth rates) to speculative (export markets we might have accessed if we didn’t have certain pests).

Conservative estimates put the annual cost at $150-200 million in direct impacts (timber losses, management costs, export disruptions). When you include opportunity costs and regional economic multiplier effects, it’s likely double that or more.

For context, the total value of Australian wood and wood product production is about $5 billion annually. Forest pests are taking a 3-4% bite out of that, year after year.

Looking Forward

Climate change is likely to increase pest pressure. Warmer conditions allow some pests to expand their range within Australia. Stressed trees are more vulnerable to attack. Some control methods (like cold winters that knock back pest populations) become less reliable.

At the same time, international trade continues to grow, creating more pathways for new pests to arrive. Container shipping, timber imports, and even mail parcels can carry hitchhiking insects and pathogens.

This means biosecurity investment will need to increase just to maintain current risk levels. The alternative—accepting higher pest pressure and its economic consequences—would be far more costly.

The forestry sector understands this. Industry contributions to surveillance and response programs have been increasing. There’s strong support for rigorous import controls and biosecurity measures, even though these create some additional compliance costs for legitimate trade.

The Bottom Line

Forest pest incursions are expensive. Really expensive. They damage timber resources, disrupt export markets, require costly eradication attempts, create permanent management costs, and harm regional economies.

The money spent on forestry biosecurity—surveillance, research, preparedness, and response—is money well spent. It’s not a cost centre; it’s risk management with a proven return on investment.

Every pest we detect early and eradicate is a bullet dodged. Every new arrival we prevent through better import controls is a long-term cost avoided.

Understanding these economics helps explain why the forestry sector takes biosecurity so seriously. It’s not regulatory box-ticking—it’s protecting billions of dollars in assets and livelihoods.