If you want to plant a forest in New Zealand, you have to control the weeds. The challenge is that environmental certification standards are restricting weed control options for forest growers. This dilemma means that weed control must be treated not as a nuisance, but as a science.

Scion is part of a collaborative research programme known as “Undermining Weeds” that provides the science skills necessary to overcome common problems faced by primary producers in New Zealand.

For forest managers, weed control is necessary to ensure tree survival and improve growth throughout the life of the stand. The key is to achieve these benefits at minimum cost while avoiding negative impacts on the environment.

Scion’s research programme aimed at forest weeds includes developing biological control options, identifying acceptable herbicides* and reducing spray volumes. Scion also provides training to forest managers on aerial spray operations, with emphasis on reducing risks from spray drift.

Timberlands Forest Risk Manager, Colin Maunder says this kind of research has been vital for the industry to achieve cost effective weed management treatment options while retaining Forest Stewardship Council (FSC) certification.

“We are keen to support the weeds programme because it shows FSC that we are serious about reducing chemical use. The research is providing good scientific information on which to base policy debates and management decisions,” he says.

The Undermining Weeds programme is a collaboration between AgResearch, Scion, Landcare Research and Plant Protection Chemistry NZ. This relatively small but highly effective programme has been identified by the Ministry of Science and Innovation as a good example of research that is delivering tangible benefits across the primary sector.

Partners within the forestry sector include Future Forests Research and the Forest Stewardship Council Cluster Group.

* A screening study of suitable herbicides for controlling five major weed species in FSC certified plantations has recently been published in the New Zealand Journal of Forestry Science (Rolando C.A., Gous, S.F., and Watt, M.S.)
See www.scionresearch.com/nzjfs

Want to know more about weed research?
CONTACT: Michael Watt
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What happens when trees become the weed?

Wilding conifers are a major weed in many areas of New Zealand. In collaboration with the Department of Conservation (DOC), Scion has developed a method for combating wilding conifers in steep terrain using aerial attack.

Trials across the South Island show that application of herbicide using a high pressure spray jet has achieved an excellent kill rate on trees up to six metres in height. This method enables a safer and faster option than manual control with chainsaws, saving over half the cost.  For more information contact
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The wilding conifer programme is a collaboration between DOC and Scion, subcontracted by Landcare Research.