Wilding conifers (also known as wilding pines) are introduced conifer trees which have self-seeded or established by natural means and have not been intentionally planted. “Conifers” refers to species of fir, larch and pine trees, and wilding conifers can be any species of introduced conifer.

Wilding conifers are any introduced conifer tree, including (but not limited to) any of the species listed in the table below, established by natural means. This doesn’t apply to conifers within a forest plantation that don’t create any greater risk of wilding conifer spread to neighbouring or nearby land than the forest plantation that it is a part of. For the purposes of this definition, a forest plantation is an area of 1 hectare or more of predominantly planted trees. This excludes planted conifers of less than 1 hectare, such as windbreaks and shelterbelts existing before March 2019.

Most wilding conifer species do not pose a significant threat to established native forests, however some species are adapting to new areas. Douglas fir in particular has a higher shade tolerance than other introduced conifer species and can consequently spread into shrublands, regenerating native and mature forests where there are canopy gaps and a relatively sparse understory.

Contorta (lodgepole) pine, Corsican pine, Scots pine, dwarf mountain pine, mountain pine and larch have very limited commercial value and are also highly invasive. Contorta (lodgepole) pine has been declared an unwanted organism under the Biosecurity Act 1993 since 2001, which means it cannot be bred, propagated, distributed or sold.

Contorta, in particular, is an unwanted organism and is the most invasive introduced conifer species.

If left uncontrolled, wilding conifers can have a huge impact on the environment. They can quickly develop into dense forests, with the potential to permanently alter ecosystems and landscapes, reduce water yields and land productivity, and limit future land use options.

Otago’s iconic landscapes are vulnerable to the invasion of wilding conifers, with around 70% of the region estimated to be “very highly vulnerable” to infestation¹. Particularly at risk are the high country and tussock grasslands — environments that tend to have short plants and sparse vegetation, as well as being lightly grazed. Wilding conifers not only thrive and dominate in these environments, but they also spread easily and extensively in windy, exposed landscapes.

Wilding conifers out-compete and push out native vegetation, particularly low-growing plant types, and dense infestations can dry wetlands and riparian areas. This loss of habitat has flow-on impacts on native fauna.

The unique character of natural landscapes can be dramatically changed by wilding conifer infestations. Stunning views can be blocked and changed, and dense infestations can block access to, and enjoyment of, recreational areas.

In areas of extensive pastoral farming, wilding conifers reduce available grazing land and if uncontrolled can limit future land use options due to the exponential increase in costs of removal once they become established. Dense infestations can reduce water yields, especially in low rainfall catchments, impacting on water availability and aquatic ecosystems. They can also heighten the risk of wildfires.

Māori cultural values can also be impacted through physical changes to culturally important landscapes, landforms, and sites; impacts on mahika kai; and potential impacts on the mauri of wetlands and waterways.

A cost-benefit analysis commissioned by MPI in 2018 quantified the economic impacts of wilding conifer infestation on productive land, water for irrigation and hydroelectricity generation, biodiversity, fire safety and household income as being $6.3 billion over a 50-year period².

Wilding conifers establish through natural seed spread, either from mature wilding conifers or from planted conifers. Seeds are mainly spread by wind but can also be moved by stock, vehicles, and machinery. Although most conifer seeds will fall within a few hundred metres of the parent tree, the seeds of some species can be blown very large distances in high wind events. Consequently, wilding conifer infestation is often characterised by scattered trees over large distances, as well as more dense growth close to the parent tree(s).

The extensive and scattered pattern of long-distance wilding conifer spread can make early detection challenging, especially in large high-country landscapes. Early detection and control are important, as control costs escalate exponentially as infestations become established.

Unchecked, wilding confers have the power to alter landscapes and cause environmental devastation.

The western, central, and northern areas of Otago have various levels of wilding conifer invasion. Many affected areas contain scattered trees, but heavily infested areas exist in western inland locations with a smaller amount of vegetation and lightly grazed. The infestation is somewhat less in the middle areas and increases slightly in the north-east.

Wilding conifers are a significant issue in the Queenstown Lakes district, where dense infestations are associated with historical plantings around settlements, eroding slopes and recreation areas, as well as commercial plantations and woodlots.

There are four rules under the programme, summarised below:

Rule 6.3.4.1

If control operations to remove wilding conifers have been undertaken on a property using public funding (either in full or in part), the occupier is subsequently required to protect this investment by removing any pest conifers on the property.

“Pest conifers” includes wilding conifers and planted pest conifers (e.g., Contorta shelterbelts).

Rule 6.3.4.2

Occupiers must remove any pest conifers on their property that are located within 200m of a neighbour’s boundary, if control operations that removed pest conifers from within 200m of the boundary have occurred on the neighbour’s property since January 2016.

“Pest conifers” includes wilding conifers and planted pest conifers (e.g., Contorta shelterbelts).

Rule 6.3.4.4

Occupiers must remove any pest agent conifers on their property that are located within 200m of a neighbour’s boundary, if control operations that removed pest conifers from within 200m of the boundary have occurred on the neighbour’s property since January 2016.

“Pest agent conifers” are non-plantation planted conifers that spread wilding conifers (e.g., Douglas fir shelterbelts).

Rule 6.3.4.3

This is a designated Good Neighbour Rule so applies to private land and Crown land.

Occupiers must remove any pest conifers on their property that are located within 200m of a neighbour’s boundary, if the neighbouring occupier is taking reasonable steps to manage pest conifers on their land within 200m of the boundary, and wilding conifers have been cleared on the neighbour’s property since January 2016.

The “reasonable steps” that the neighbouring occupier is taking may include:

• Removal of mature pest conifers
• Removal of seedling wilding conifers
• Regular monitoring for wilding conifers, and removal of them if found

“Pest conifers” includes wilding conifers and planted pest conifers (e.g., Contorta shelterbelts).

Contorta shelter belts and other conifer shelter belts are often used to provide shelter for stock. It can be difficult to successfully control or manage the spread of wilding conifers over the long term if the existing planted seed sources are not removed or appropriately managed and contained. The pest plan does not require you to remove existing shelter belts and other existing planted conifers less than 1 hectare. However, ORC’s Biosecurity Strategy sets out transition arrangements for their long-term removal, starting with the removal of Contorta shelter belts.

Preventing the spread of wilding conifers is one of the most important actions landowners and occupiers can take to protect Otago’s unique landscapes, primary industry, tourism, and the economy from the impact of wilding conifers.

However, achieving the RPMP and national objectives for wilding conifers will require landowners and occupiers, community groups, industry, researchers, and local and central government to work together. And although land occupiers are responsible for controlling wilding conifers on their land, there is a role for all New Zealanders to be aware of this expanding issue, and support taking action.

If you have any questions about wilding conifers in Otago, your responsibilities as an occupier, or ways you can get involved in wilding conifer control, please contact:

The ORC biosecurity team

• Email biosecurity@orc.govt.nz
• Call 0800 474 082

Or the community wilding conifer control group nearest you.

Wilding conifer: Any introduced conifer tree, including (but not limited to) any of the species listed in the Otago Regional Pest Management Plan 2019-2029, established by natural means unless it is located within a forest plantation, and does not create any greater risk of wilding conifer spread to adjacent or nearby land than the forest plantation that it is a part of.

Pest conifer: Includes any wilding conifers and planted pest conifers (e.g., Contorta shelterbelts) listed in the Otago Regional Pest Management Plan 2019-2029, including Corsican pine, European larch, Scots pine, contorta pine, mountain pine and dwarf mountain pine.

Pest agent: Any introduced planted conifer that is contributing toward the establishment and spread of wilding conifers. It excludes trees located within a plantation forest. Defining conifers as pest agents intends to look further than those that are Wilding or already classed as pests and address other planted species that are causing harm and contributing to Wilding conifer spread.

<sup>1. Wildlands Contract Report No. 3754a prepared for MPI. Methods for the Prioritisation of Wilding Conifer sites across New Zealand. February 2016.
2. Wyatt, S., 2018, Benefits and Costs of the Wilding Pine Management Programme Phase 2, Sapere</sup>

orc.govt.nz/wildingconifers