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
All plants on MPI's National Pest Plant Accord (NPPA) are unwanted organisms under the Biosecurity Act 1993 whose formal or casual trade contributes significantly to their spread.
Plants on the Accord cannot legally be propagated, distributed, or sold in New Zealand. If allowed to spread further, these pest plants could seriously damage our economy and environment.
Progressive Containment Programme
There are a number of pests that are well established in the Hawke’s Bay region but their present infestation levels are still low enough for those levels to be reduced region-wide through a progressive containment programme. Progressive Containment programmes have the less specific aim of reducing levels of infestation within their respective management zones. While the general intent is to reduce these infestations to zero-levels at some time into the future, the primary focus of a progressive containment programme is to preventing a pest from spreading. For well-established pests whose harmful effects and spread can still be reduced, progressive containment offers the best ratio of cost to benefits.
The goal is to maintain a pest population at the lowest feasible level and confine it to a particular area while reducing numbers over time. In some cases this will result in fewer sites infested or in others the overall density of the pest will reduce over a 10 year duration period. Containment programmes usually target habitats of high ecological value that require protection and restoration.
Rules
Sections 52 and 53 of the Biosecurity Act (1993)
No person shall knowingly communicate, cause to be communicated, release, or cause to be released, or otherwise spread any pest or unwanted organism, in accordance with Sections 52 and 53 of the Biosecurity Act 1993
More informationPlan Rule 8
Except where an occupier of land has entered into a Written Management Agreement approved by Hawke's Bay Regional Council, an occupier, on receipt of a written direction from an Authorised Person, shall destroy all wilding conifers, Scots pine, mountain pine and dwarf mountain pines present on land they occupy within 200 metres of an adjoining property boundary prior to cone bearing, if the occupier of the adjoining property is taking reasonable steps to manage wilding conifers on their land, within 200 metres of the boundary.
More informationPlan Rule 7
Except where an occupier of land has entered into a Written Management Agreement approved by Hawke's Bay Regional Council, an occupier of land shall:
a) destroy all contorta plants on their land prior to cone bearing; and
b) destroy all Scots pine, mountain pine and dwarf mountain pine on their land within the containment area defined in Figure 10 prior to cone bearing; and
c) destroy all wilding conifers present on land they occupy prior to cone bearing, if
I.The wilding conifers are located within an area which has had control operations carried out to destroy wilding conifers or any other planted conifer species that were causing the spread of wilding conifers; and
II.The control operations were publicly funded (either in full or in part).
Good Neighbour Rule (GNR)
The "Good Neighbour Rule", under the New Zealand Biosecurity Act (1993), requires occupiers of land to take measures to prevent certain pests from spreading to adjacent properties. There are a number of pests where regulatory control within a property is unwarranted because occupiers make adequate control decisions based on their individual requirements. However, the ease that a pest spreads means that controlling property boundaries may still be required. The Good Neighbour Rule also applies where pest control along a property boundary is deemed inadequate.
More informationTaxonomies
FamilyPinaceae
TypePlants
GroupTree
HabitatLand
Management ProgrammeNational Pest Plant AccordProgressive Containment Programme
RulesSections 52 and 53 of the Biosecurity Act (1993)Plan Rule 8Plan Rule 7Good Neighbour Rule (GNR)
