Northern infestation threatens Molesworth conifer control

Saturday, 15 March 2025

Wilding pine seedlings popping up in Tarndale, Molesworth. An incursion of wilding pines north of the reserve in South Marlborough could be the source of the seeds.

John Oswald is the chairperson of the South Marlborough Landscape Restoration Trust.

OPINION: A recent Weekend Express article (March 1) outlined how the International Visitor Levy will help fund the MPI National Wilding Conifer Control Programme (WCCP) that runs the wilding pine control work on Molesworth Station.

This huge environmental problem is not just confined to Molesworth, and elsewhere in Marlborough the South Marlborough Landscape Restoration Trust (SMLRT) has been tackling wilding conifers.

Over the last eight years, the trust has cleared wildings from 80,000ha in the Upper Awatere, 24,000ha in the adjacent Ferny Gair block and 10,000ha at Black Birch, plus 20,000ha in the Ned.

Contorta pines spread above the native bush line in the Lower Silverstream Valley, a tributary of the Branch River.

However the elephant in the room is the 52,000ha Branch/Leatham catchment. This is arguably NZ’s worst wilding pine infestation and lies to the north of Molesworth between the top end of the Wairau River and the northern boundary of Molesworth Station.

Contorta pines and douglas fir were planted here by the NZ Forest Service in the 70s and 80s, against the advice of local high country farmers.

Periodic seed rain events caused by the prevailing north-west wind have contaminated the high country south of this block and during operational work in the Awatere SMLRT found 30 patches of contorta which almost certainly resulted from seed blown in from the Branch/Leatham 25km away.

South Marlborough Landscape Restoration Trust chairperson John Oswald with a tiny wilding pine plucked from the Awatere.

Without the current control work these trees will eventually go all the way to Kaikōura.

Recently thousands of hectares of Molesworth and neighbouring Muller Station have been contaminated by seeds blowing through the Saxton Saddle from the Upper Leatham.

And herein lies the dilemma. $12 million has been spent so far by the NWCCP on wilding control work on Molesworth, but unless the source of this seed is dealt with, the campaign on Molesworth cannot succeed, and the $12m expenditure will have been in vain.

SMLRT has, in the last two years, started operational work in the Branch/Leatham and is currently wanding from helicopters the scattered wildings in the 10,000ha Raglan Tops sector, utilising a $450,000 grant from the Rata Foundation who have been a very supportive funder, and a believer in the trust’s ultimate aim to have the Branch/Leatham included in the National Programme.

As a part of its advocacy work the trust has also produced a detailed, peer reviewed, Ten Year Plan to demonstrate that it is possible to tackle this huge weed problem that has the potential to wreck all of the Marlborough high country.

SMLRT was formed in 2016 and has four part-time employees to co-ordinate our operational work, run the admin and volunteer programme and conduct advocacy work on behalf of the trust and the nationwide Wilding Pine Network.

SMLRT is managed by seven trustees and ex-officio board members from DOC, LINZ and MDC, and receives much appreciated funding support from MDC and DOC.

However the operational work is paid for from money (in excess of $1.5m) that we have raised from the Lotteries Commission, Rata Foundation and contributions from landowners.