Call to tackle wilding conifer spread in Northland

 

The increasing impact wilding conifers are having on Northland’s coastal margins, dune lakes and rare gumland ecosystems has prompted the Northland Regional Council (NRC) to drive the push – with assistance from Landcare Research – to fully assess the extent and impact wilding conifers are having on the North.

Council Biosecurity Manager Don McKenzie says wilding conifers have long been an issue in Northland, many of them the descendants of escapees from commercial forestry plantations or shelter belt plantings decades ago.

He says the regional council does have rules requiring control of wilding pines along property boundaries – but not wider controls for the trees – in its Northland Regional Pest and Marine Pathways Management Plan 2017-2027.

Wilding conifers can comprise several species; cedars, pines (including pinus radiata), firs, cypress, larches, and spruces. While the impacts of wilding conifers in the South Island are well-known and understood – and have attracted significant control funding in recent years – the situation in Northland is less-clear.

“We know from our staff’s own observations in the field, and our examination of recent aerial imagery, that wilding pines are having an increasing, and unwanted, impact on our coastal margins, dune lakes and rare gumland ecosystems.”

The problem appears to be worsening with wilding pines slowly increasing their reach and scale, especially in places like the Ngunguru Sandspit and dune lakes in both the Far North are and the Kaipara District, including the Kai Iwi Lakes system.

“Wilding conifers are an issue because not only do they colonise and change the existing environment, displacing native species, they can adversely impact on water tables. Roadside wilding conifers can also be problematic for power and other infrastructural companies, costing them significant sums to trim and remove to protect that infrastructure from potential tree-related damage.”
Northland’s sub-tropical climate also appears to be especially favourable to the conifers, which are typically unwanted commercially because their poor form and heavy branches result in low grade logs which have minimal value.

Mr McKenzie says he believes wilding conifers should be attributed the same pest status as other species like wild ginger, given their potential impacts on the region.

NRC was now in the process of convening a regional stakeholder group of key agencies and interests in February to examine the wider wilding conifer issue. 

Biosecurity Manager Don McKenzie with a wilding conifer.