Wilding conifers

Common name: Wilding conifers

Botanical name: See table

Management programme: Progressive containment

                

Wilding conifers are an invasive pest tree that affects landscapes and pastoral productivity across New Zealand, including Otago.

It is estimated that wilding conifers are spreading at around 5% annually. Failure to control their spread at an early stage can quickly lead to increasing numbers of trees taking hold, and the costs of control escalating exponentially. This is the case in parts of Otago, where the cost of eradicating some areas of historically-planted conifers (known as legacy plantings) has now become prohibitive.

Wilding conifers are any introduced conifer tree, including (but not limited to) any of the species listed in Table 3, established by natural means. This doesn’t apply if 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 1ha or more of predominantly planted trees. This excludes planted conifers of less than 1ha, such as windbreaks and shelterbelts existing before March 2019.

               

                  

Progressive containment programme

The progressive containment programme aims to stop a pest from spreading and/or contain it to a certain area.

Regional Pest Management Plan

Why are they a pest?

Wilding conifers can have significant impacts on native ecosystems, by shading out low-stature native plants. Where there is thick wilding conifer growth, this can lead to local extinction of native plant communities, the drying of wetlands and riparian areas, and resulting impacts on native fauna through the loss of habitat. Soil and soil fauna are also altered when wilding conifers replace native ecosystems.

Otago’s iconic landscape is vulnerable to the invasion of wilding conifers. If not controlled, they would significantly change the landscape and impact on our recreational, hydrological and conservation values. Particularly at risk is our high country and tussock grasslands. The growing problem has been recognised for some years and as a result, the Wakatipu Wilding Conifer Control Group and the Central Otago Wilding Control Group established themselves solely to fight wilding conifers.

Click here to see images

                         

What are the rules?

Over the life of the pest plan (10 years) the goal is to ensure that the spread of wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch doesn’t cause unreasonable costs to the occupiers of neighbouring properties where control operations have taken place, or where the neighbouring occupier is undertaking active wilding conifer management.

Below are the rules for wilding confiers in our pest plan, these can be complex so if you want to someone in our biosecurity team about these rules call ORC on 0800 474 082 or email pests@orc.govt.nz.

Plan Rule 6.3.4.1 Within the Otago Region occupiers shall destroy all wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch present on land that they occupy prior to cone bearing, if:

  1. The wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines, and/or larch are located within an area which has had control operations carried out to destroy wilding conifers since January 2016; and
  2. The control operations were publicly funded (either in full or in part).

Plan Rule 6.3.4.2 Within the Otago Region occupiers shall destroy all wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch present on land they occupy within 200m of an adjoining property boundary prior to cone bearing, if:

  1. Wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch have previously been destroyed through control operations on the adjoining property; and
  2. The control operations on the adjoining property were within 200m of the boundary and were undertaken since January 2016.

Plan Rule 6.3.4.3 (Note: This is designated a Good Neighbour Rule) Within the Otago Region occupiers shall destroy all wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch present on land they occupy within 200m of an adjoining property boundary prior to cone bearing where:

  1. The adjoining land has previously been cleared through control operations since January 2016; and
  2. The occupier of that adjoining land is taking reasonable steps to manage wilding conifers, contorta, Corsican, Scots, mountain and dwarf mountain pines and/or larch on their land, within 200m of the boundary.

 

The different types of wilding conifers

Table 3: Introduced conifer trees in our pest plan

Common name

Botanical name

Bishops pine

Pinus muricata

Contorta (lodgepole) pine

Pinus contorta

Corsican pine

Pinus nigra

Douglas fir

Pseudotsuga menziesii

Larch

Larix decidua

Maritime pine

Pinus pinaster

Mountain pine and dwarf mountain pine

Pinus mugo and P.uncinata

Ponderosa pine

Pinus ponderosa

Radiata pine

Pinus radiata

Scots pine

Pinus sylvestris

 

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 forest and mature forest 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. This is why these are defined as pests in their own right as well as coming under the wilding conifer definition. This stops new plantings of these species and also ensures that where they are cleared using publicly funded control operations, stay clear.

Contorta in particular, is an unwanted organism, is the most invasive introduced conifer species and represents a significant proportion of all wilding conifers and original sources of wilding conifer spread.

           

What if I use conifers for my shelter belt?

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 1ha. However, ORC’s Biosecurity Strategy sets out transition arrangements for their long-term removal, starting with the removal of Contorta shelter belts.

       

What are we doing?

A National Wilding Conifer Control Programme has been developed and funded by government agencies, landowners and local communities to address infestations. The extent within Otago ranges from very dense wilding infestations in the Wakatipu area, through to very low wilding conifer numbers scattered over thousands of hectares. Control efforts to date have been very successful where the work has been carried out, but will require an ongoing effort for many years to come in follow-up work, and in areas where control is yet to be undertaken. The seed source for spread is, in some cases, from planted conifers in the form of shelterbelts and forestry plantations. ORC will work proactively with land occupiers with planted shelter belts and forestry plantations to reduce spread.

The graph below shows the estimated increase across Otago in hectares infested by wilding conifers over the next 20 years if the present management regime continues.

 

In 2015, a national wilding conifer management strategy was developed, promoting a co-ordinated and collaborative multi-agency approach to wilding conifer management by relevant agencies. Several groups are already actively engaged in the control of wilding conifers across Otago.

ORC administer central government funding for the control of wilding conifers in Otago. We also collect a regional rate to support community groups undertaking control work.

The Queenstown community-run Wakatipu Wilding Control Trust has produced a wilding conifer control strategy. This trust, and the Central Otago Wilding Conifer Control Group, which has developed its own strategy, have put thousands of volunteer hours into containing, controlling and eradicating wilding conifers.

       

Which parts of Otago are most infested with wilding conifers?

The western, central and northern areas of the region have various levels of wilding conifer invasion. Many affected areas contain scattered trees, but heavily infested areas exist in western inland locations that are lightly vegetated 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.

 

Images

            

Douglas fir - Source: Weedbusters

Douglas fir - Source: Weedbusters

             

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

          

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

            

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

            

Marty Grounds of Groundspray Environmental Weed Control instructs participants on wilding pine control methods at a 2014 ORC field day near Naseby

Marty Grounds of Groundspray Environmental Weed Control instructs participants on wilding pine control methods at a 2014 ORC field day near Naseby

       

Spread adjacent to Naseby forest

Spread adjacent to Naseby forest

         

Hills behind Alexandra. Photo: Chris Pascoe

Hills behind Alexandra. Photo: Chris Pascoe

           

Douglas fir - Source: Weedbusters

Douglas fir - Source: Weedbusters

             

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

            

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

          

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

             

Volunteers get ready for a day of wilding control at Ben Lomond, Queenstown in 2011. Photo: ODT

Volunteers get ready for a day of wilding control at Ben Lomond, Queenstown in 2011. Photo: ODT

             

Kakanui Range

Kakanui Range

Douglas fir - Source: Weedbusters

Douglas fir - Source: Weedbusters

                 

Douglas fir - Source: Weedbusters

Douglas fir - Source: Weedbusters

           

              

Contorta pine - Source: Weedbusters

Contorta pine - Source: Weedbusters

         

Department of Conservation ranger Brenton Wilson watches as a helicopter sprays wilding conifers above Fernhill, Queenstown in January 2015. Photo: ODT

Department of Conservation ranger Brenton Wilson watches as a helicopter sprays wilding conifers above Fernhill, Queenstown in January 2015. Photo: ODT

            

Upper Manuherikia with Hawkduns in background

Upper Manuherikia with Hawkduns in background

            

Hills southeast of Alexandra

Hills southeast of Alexandra

    

Definitions

Land occupier – An occupier is the person who physically occupies the place, the owner of the place and any agent, employee, or other person acting or apparently acting in the general management or control of the place. For example if you are renting a house owned by someone else that does not live on that property, you are the occupier and are responsible for pest management under the pest plan. You can see more about the responsibilities of occupiers (including owners) in section 3.3.1 of the pest plan.

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