An international biosecurity conference started in Rotorua on Monday.
About 150 forestry scientists, managers and policy makers from around the world are attending the conference.
Dr Brian Richardson, of New Zealand's forestry research institute, Scion, which is hosting the conference, says it is an opportunity to assess the growing threat to forests from pests and diseases and how to counter the sorts of biosecurity risks that New Zealand has already experienced.
Dr Richardson says it is important to avoid getting to the point where an eradication programme, such as that used against the painted apple moth in Auckland, is needed.
The conference will also consider issues such as managing vegetation without herbicides and finding alternatives to the fumigant methyl bromide, used to control quarantine pests. Use of the gas has become an issue because it depletes the ozone layer and is toxic to the human nervous system.