Wilding conifers, also known aswilding pines, areinvasive trees in thehigh country ofNew Zealand. Millions of dollars are spent on controlling their spread.[1]
In theSouth Island they threaten 210,000 hectares of public land administered by theDepartment of Conservation. They are also present on privately owned land and other public land such as roadsides. The wilding conifers are considered to be a threat tobiodiversity, farm productivity and to landscape values. Since they often invadetussock grasslands – which are characterised by low-lying vegetation that is considered to be anatural environment – the tall trees become a prominent and unwanted feature.
There are ten main species that have become wildings:[2]
The various species dominate in different areas of New Zealand. Radiata pine (Pinus radiata) is used for 90% of the plantation forests in New Zealand[3] and some of the wilding conifer is a result of these forests.
Without any control measures, wilding conifers will spread over an increasing area with economic and environmental consequences. As well as volunteers organised by environmental groups, regional councils and the Department of Conservation invest in wild conifer removal.[citation needed]
A South Island Wilding Conifer Management Group was formed in 2006 and obtained funding from theMinistry of Agriculture and Forestry Sustainable Farming Fund.[4]
Mechanical removal by hand pulling seedlings, and the use of brush cutters andchainsaws are common control methods. Spray trials are also being carried out. In 2004 a spraying operation by the Department of Conservation at Mid Dome in theSouthland region causedspray drift onto surrounding areas including the towns ofAthol andKingston.[5]
Pest management is administered byregional councils. There are sixteen differentregions in New Zealand and wilding conifers only occur in a few of these regions, predominantly in the South Island. TheDepartment of Conservation manages wilding conifers on public land under its jurisdiction.[citation needed]
In its 2005 Pest Management Strategy theCanterbury Regional Council (Ecan) has the objective of eradicating all self-sown wilding conifers in ecologically sensitive areas in its jurisdiction. To do this a range of measures are used, including carrying out wilding conifer control operations, encouraging reporting of the presence of wilding conifers, encouraging the removal of seed sources and advocating changes to the district plans of theterritorial authorities to prevent or control the planting of inappropriate conifers.[6]
Wilding conifers infest theKaweka Forest Park.[citation needed]
Pinus contorta infests the south Marlborough area and is classed as a "Containment Control Pest", which are pests that are managed to prevent spreading to new areas. Other wilding species exist in Marlborough but Lodgepole Pine is the focus for pest management.[7]
Pinus contorta is a pest plant listed in theOtago Regional CouncilPest Management Strategy for Otago.[8]
A major area of wilding conifer spread is in the Mid Dome Area in theSouthland region. TheMid Dome Wilding Trees Charitable Trust was set up in 2006[9] and in 2008 the government allocated $54,000 from the Biodiversity Funds to control wildings on about 1,000 hectares (2,500 acres) in the area.[10]
