Conifers

(Wilding Conifers / Pest Conifers)

Common name: Wilding conifers and pest conifers (cedars, pines, firs, cypress, larches, and spruces) 
Botanical name: Pinus spp. 
Management programme: Sustained Control Rule 5, Progressive Containment 

Why are they pests?

• Wilding and pest conifers can have significant impacts on native ecosystems, particularly areas of low-stature native plants. They disrupt soil composition and nutrient levels, inhibiting native plant growth. 
• Species such as dwarf mountain pines invade alpine scree slopes, altering erosion processes. 
• Their growth reduces surface water flows, affecting aquatic ecosystems and water availability. This contributes to lower water yields, especially in sensitive catchments. 
• Their groundwater extraction patterns contribute to droughts and floods while infestations reduce available grazing land and increase land control costs. 
• Dense stands limit future land use options and thrive even on poor soils. 
• Lodgepole pines are particularly invasive, dominating large areas. They pose the biggest threat to highly vulnerable and critically threatened frost flat ecosystems. 
• Many conifer species are fire adapted and burn easily, therefore their spread increases wildfire risk, particularly in dry conditions. 
• Dense infestations diminish landscape and amenity values, impeding access to and enjoyment of recreational areas. 

Where are they found?

• Risk areas include frost flats, native forests, clearings and high country. 
• Wildling conifers are spread via wind dispersal, where seeds can be carried long distances by the wind. 
• Wilding pines can be found throughout the Bay of Plenty. The worst affected areas are the upper Rangitāiki, Mt Tarawera, Te Urewera and East Cape. 

What do they look like?

• A conifer is a tree that bears cones and has needle-like or scale-like leaves that are typically evergreen. 
• The term wilding conifer applies to any introduced conifer species when in its wilding form, self-seeded and growing without human support. 
• Conifer species recognised as currently contributing most to the wilding conifer problem include a range of cedars, pines, firs, cypress, larches, and spruces. 

Spot the differences in each species.

What are the rules?

The various wilding and pest conifer species present in the Bay of Plenty are classified as either Sustained Control or Progressive Containment pests, as outlined in the table below: 

Sustained Control 

Sustained Control pests are well established in the region and preventing the spread is no longer a realistic objective. Management focuses on reducing general impacts of the pest. Landowners/occupiers are responsible for the control of these pest species on their land. The Regional Council may enforce control. 
 
Occupiers must destroy wilding conifers if they are either within 200m of any property boundary where the adjoining occupier is also controlling them OR if required by a written direction from an authorised person. 

Progressive Containment 

Progressive Containment pests are those that the Regional Council aims to prevent from spreading, reduce the distribution, or eradicate within parts of the region over time. Landowners or occupiers are responsible for the control of Progressive Containment species on their property. The Regional Council may enforce the control of these pest species. 

How do you get rid of it?

Recommended: 

• Hand pulling:  
  Small seedlings can be hand pulled or dug out. Ensure roots are completely removed from the ground and soil is shaken from them. 
• Drilling and injecting:  
  Drill holes at a downward angle about 50mm into the trunk. 
  Holes should be spaced about 200mm apart around the trunk. Fill with neat herbicide. 
• Ground basal bark application:  
  An oil-based herbicide designed to penetrate basal bark has been developed, and offers advantages over foliar spraying and more labour-intensive methods of delivering herbicide internally to the trunk. The herbicide is applied as a wide collar around the trunk.  
• Felling:  
  Felling is an effective method of control provided all live foliage is removed from the stump. If this is not possible because of the terrain, herbicide should be applied to the stump. 
• Aerial spraying - Aerial basal bark application:  
  Helicopters are sometimes used to apply herbicide via a nozzle on a long lance. This method is particularly useful for covering trees spread widely across the high country and can be the only practical way to control trees growing on cliff faces. 

CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.

Read more on pest control advice, information and regulations