What does it look like?
Conifers are woody plants that have cones instead of flowers. Leaves are needle like and have a resinous scent when crushed. They include cedars, pines, firs, cypress, larches, and spruces. Trees can grow up to 70 metres tall. Wilding conifer is the New Zealand term for introduced conifers that are spreading across the landscape – self-sown and unwanted. Ten introduced conifer species are responsible for most wilding infestations, and are listed for Progressive Containment in Hawkes Bay’s Regional Pest Management Plan.
|
COMMON NAME |
SCIENTIFIC NAME |
|
Douglas Fir |
Pseudotsuga menziesii |
|
Contorta pine |
Pinus contorta |
|
Scots pine |
Pinus sylvestris |
|
Mountain pine and Dwarf mountain pine |
Pinus unicinata and Pinus mugo |
|
Bishops pine |
Pinus muricata |
|
Maritime pine |
Pinus pinaster |
|
Ponderosa pine |
Pinus ponderosa |
|
Corsican pine |
Pinus nigra |
|
European larch |
Larix decidua |
|
Radiata pine |
Pinus radiata |
Two of these species - radiata pine and Douglas fir - are also important commercial species, but only when the trees are planted in an appropriate place, at suitable spacings, and tended as they grow.
One species, the lodgepole (contorta) pine has been declared an unwanted organism under the Biosecurity Act 1993, which means it cannot be bred, propagated, distributed or sold.
Wilding conifers can grow in a range of habitats, including grasslands, shrublands, scrub riparian ecosystems and coastal dunes, from high altitudes to near sea level. Low stature native vegetation and ecosystems such as shrublands are particularly vulnerable to invasion.
Spread by seeds, they can start reproducing at 8 years of age, or even younger in some cases. Known seed viability ranges from 4 years (Pinus contorta) to 15 years (Pseudotsuga menziesii).
Why is it a problem?
When conifer cones mature on the tree, they open to release masses of wind-blown seeds. These seeds travel kilometres downwind and need no special conditions to take root and grow.
Without control, dense forests can form that have environmental consequences, using up water and altering landscapes significantly, displacing native plants and animals. Wilding conifers are a major problem in areas where there is no native forest, such as above the bush line, in mineral belts and tussock grasslands.
In native forests, wilding conifers compete for space with native trees and plants and don't provide the advantages that native trees do, like food for native birds or insects. Their needles form an acidic carpet which discourages regeneration of native forest floor species.
While wilding conifers are a pest, planted conifers are a valuable resource. For this reason, the ‘wilding conifer’ definition incorporates all ten of the most spread-prone conifer species but specifically applies only to those trees that are naturally regenerated rather than intentionally planted.
Control methods
Herbicide control
Drill holes at 100mm intervals around the trunk and fill with undiluted glyphosate or metsulfuron-methyl (600g/kg e.g. Escort ®) mixed at 20g/L water. Or,
Spray a collar around the trunk with one part triclopyr (eg Grazon®) to three parts biodiesel (eg Codacide®).
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
More information
On behalf of the Ministry of Primary Industries, we administer the National Wilding Conifer Control Programme in the region where it relates to privately owned land, conducting control operations in areas most affected by wilding conifer spread or to eliminate existing seed sources.
We work collaboratively with regional neighbours – Horizons, Bay of Plenty Regional Council and the Department of Conservation to coordinate these programmes.
We also enforce Plan Rules 7 & 8 which relate to the destruction of wilding conifers present on private land.
Related links
Management Programme
National Pest Plant Accord (NPPA)
The NPPA is designed to prevent the sale, distribution and propagation of a set list of pest plants (the Accord list) within New Zealand. If allowed to spread further, these pest plants could seriously damage the New Zealand economy and environment.
More informationProgressive Containment Programme
To contain or reduce the geographic distribution of the subject, or an organism being spread by the subject, to an area over time.
Rules
Sections 52 and 53
Sections 52 and 53 of the Biosecurity Act 1993, which prevent the communication, release, spread, sale and propagation of pests, must be complied with.
Taxonomies
FamilyPinaceae
TypePlants
GroupTree
HabitatLand
Management ProgrammeNational Pest Plant Accord (NPPA)Progressive Containment Programme
RulesSections 52 and 53
