A global strategy needed for forest health and biosecurity

21 August 2015

Maintaining successful biosecurity systems is vital for protecting our forests assert the authors of a review published today in the prestigious journal “Science”.

Forests worldwide are continually under threat from introduced insects and pathogens despite the best biosecurity efforts. Without a concerted global effort to understand and control invasive pests the problem is expected to worsen as international trade increases.

“Keeping invasive pests out of forests should be a top priority for all countries,” according to Dr Eckehard Brockerhoff, Principal Scientist at Scion and a co-author of the review that considers the need for a global strategy to keep planted forests healthy.

“Planted forests of radiata pine have been successful partly because the trees have been separated from their natural pests. The downside is that they are also vulnerable if these pests accidentally arrive or if trees encounter new pests for which they have no resistance.”

“Keeping forests secure relies on quarantine, treatment of imported goods, and monitoring insect traps and trees around ports and other high risk sites. When these biosecurity measures are applied strictly they work very well. New Zealand has some of the best practices in the world.”

“But global biosecurity is only as strong as the weakest link. Many countries don’t have the resources to put biosecurity measures in place for plants and plant products. Once a pest becomes established it can be impossible to eradicate, and the pest can use the new country as a stepping stone for further invasions.”

“For example, pine pitch canker disease, caused by the pathogen Fusarium circinatum, is one of the worst diseases of pines. It has already invaded eight countries, and at least some of these invasions could have been prevented through better awareness and regulation of plant movements.”  

“The only way we can realistically deal with tree pests will be through global collaboration - sharing experience and research findings. While bodies like the International Union of Forest Research Organisations (IUFRO) help to facilitate collaboration, there is no single body or funding structure to support a global strategy for dealing with pests in planted forests.”

Dr Brockerhoff and his co-authors from the University of Pretoria say the perfect time to talk about this issue is now because the World Forestry Congress of the Food and Agriculture Organisation of the United Nations is focussing on forest health and sustainability when it meets in September in South Africa.

Forests are natural resources of global significance. They regulate climate, store carbon, prevent erosion and improve water and air quality and at least one in six people relies on forests for food and their livelihood. In New Zealand, the planted forestry industry is the third largest export earner and contributes around $5 billion a year to the economy.

Crucial to preparing for future pest invasions is not just recognising there is a problem but also investing in research and innovation. Scientists at Crown research institute Scion and other organisations in New Zealand and overseas are using techniques such as introducing natural predators (or biological control), knowledge of tree genetics and an improved understanding of forest ecosystems to develop non-chemical methods for controlling existing pests and preparing for future threats.

New Zealand is considered a world leader in biosecurity, but it is not possible to exclude all forest pests and pathogens forever.

“We have excellent systems in place to prevent the arrival of forest pests and diseases, to respond to incursions of potential threats, and to manage those that do become established,” said Dr Brockerhoff.

“But single country strategies will not be sufficient as the threats to both planted and indigenous forests are increasing worldwide.”

With increasing globalisation and international trade it is important for New Zealand to maintain strong international networks to address the biosecurity challenge collectively and, through science partnerships, help countries that may not have the resources or expertise to put biosecurity measures in place.