28 August 2012
A report prepared for the Ministry for Primary Industries recommends that a national strategy be prepared for wilding conifer management. It also recommends an accord be developed between the forestry industry, Local Government New Zealand, MPI, the Department of Conservation and LINZ.Wilding Conifers in New Zealand: Beyond the status report, was prepared by Victoria A Froude for Pacific Eco-logic Limited. It assesses the wilding conifer situation across the country and identifies ways to improve wilding conifer management.
The many parties on the Wilding Conifer Management Group (WCMG) were consulted during the preparation of the report and have endorsed its recommendations.
Ten introduced conifer species are responsible for most wilding conifers. While many of these species are not now planted commercially, some (e.g. radiata pine and Douglas fir still are.
Contorta pine (Pinus contorta) is the most invasive introduced conifer species and is an “unwanted organism” under the Biosecurity Act. Other introduced conifers that produce unwanted wildings include Scots pine (Pinus sylvestris), Mountain pines (Pinus mugo subsp mugo & Pinus subsp uncinata), Corsican pine (Pinus nigra), Douglas fir, European larch (Larix decidua), Ponderosa pine (Pinus ponderosa), Muricata pine (Pinus muricata) and Maritime pine (Pinus pinaster).
In a 2007 survey, some 805,000 ha of the eastern South Island were found to be affected by wildings. This included 185,000 ha mapped as having a wilding cover and a 660,000 ha that had received past control but were thought to still have wilding conifers (albeit at low levels). Wilding conifers in the North Island have not been fully mapped although it is estimated that approximately 300,000 ha are affected at various densities.
Wilding conifers grow faster and taller than low-stature indigenous vegetation. Indigenous ecosystems that are at particular risk from wilding conifer invasion include: tussock and other indigenous grasslands, alpine ecosystems, subalpine and dryland scrub and shrublands, frost-flats, wetlands, turf communities, geothermal areas, dunelands, ultramafic/serpentine areas, rockfields and herbfields, riparian areas, coastal margins, bluffs and cliffs. A number of the more invasive wilding conifer species (e.g. contorta pine, mountain pine and Corsican pine) are able to grow at altitudes above the treeline formed by indigenous forest species.
Wilding conifers that grow above the native treeline cannot be replaced by native species as part of natural succession processes. In some cases wilding conifer spread may lead to the local extinction of native plant communities and populations of native plant and animal species. Soil properties and soil fauna are also changed when introduced conifers replace native ecosystems.
MPI will lead further work to implement the key recommendations of the Froude report through the development of a non-regulatory strategy.
To read the report, click here.