Wilding pines a ticking time bomb

John Oswald Chairman of the South Marlborough Landscape Restoration Trust describes the 52,000 Hectares of the Branch Leatham Valley “a ticking time bomb of compounding seed-rain dispersal.” “Without commitment to a plan to eradicate wilding pines, these trees will replace indigenous biodiversity and tussock in the mountain landscapes of South Marlborough, all the way to Kaikoura.”  The efforts of SMLTRT to restore and protect alpine landscapes and native diversity by controlling wilding pines covers 870,00 Hectares of the region.

On a recent Field Day at The Muller Station attendees were shown herbicide treated pine seedlings that had travelled 30kms downwind from source plants. Station owner, Steve Satterthwaite believes that within 20 years 28,000ha of pastoral lease will be populated by impenetrable pines, unless they are controlled.

A ten year, operational, peer reviewed plan, and budget has been developed by the Trust to demonstrate the feasibility and time frame of possible control options in the Branch/Leatham.This is estimated to cost $100 million over ten years.The proliferation of wilding pines threatens the increased incidence of wildfires and ground water availability. The impenetrable trees impact the region’s tourism, hydroelectricity, agricultural viability, and viticulture as well as at least 29 nationally threatened or at-risk plant species, occurring in the area. In a recent study in Otago, replacement of tussock with pine species predicted up to 45% loss of water yield. If 500,000 Ha of Mackenzie Country were forested in wilding pines there would be an estimated reduction in water flow of twice the median flow of the Clarence River. It is estimated that within 30 years more than 25% of New Zealand could be covered in wilding pines, unless the problem is controlled. For years the Ministry of Primary Industries funding focus has been on eradicating trees in the Rangitahi/Molesworth areas with the Branch/Leatham being put into the ‘too hard basket’. A three-year, $450,000 grant from the Rata Foundation is supporting the operational efforts of SMLRT and volunteers on the ground in the Branch/Leatham. This has allowed the Trust to raise awareness of the issue with local and central government.  Primarily formed in 2016 by concerned environmentalists the Trust has already cleared approximately 134,000 hectares in the Awatere, Ferny Gair/Black Birch and Lower Wairau areas,with 100% local landowner buy in. Oswald firmly believes that unless their spread is controlled, the introduction of the trees will prove to have a worse effect on the environment than other misguided man-made additions, such as rabbits, deer and pigs. Failing to tackle the Branch Leatham wilding pine problem will result in the reinfestation of areas such as the Molesworth and surrounding high country properties, where millions of dollars have already been spent on eradication. The trees that created this problem were originally sown by Government Forest Services, supposedly to prevent erosion, but the extent of future spread was not considered at the time. Ironically the Branch/Leatham runs had been abandoned because of their tendency to revert to native scrub such as manuka. Had the land been left alone it would have quickly been covered in native bush which would have contained any likely erosion. Wilding pines have however shown remarkable resilience and are now establishing at higher altitudes above the bush line, so will have to be controlled if the spread of seed is to be curtailed.

SMLRT estimate that to continue with the programme of eradication $100 million will be required over ten years. Where will the money come from? Marlborough District Council Environment Manager, Alan Johnson recently implied that the future of some core environmental projects may be ‘hanging in the air as funding dries up’. Marlborough was given $37.4 million to fund six projects until 2027 as part of the previous government’s $1.2 billion ‘Jobs for Nature Programme’ in May 2020.  SMLRT’s representatives are constantly lobbying government ministers in Wellington, ensuring that the authorities are aware of the problem and of the urgency of tackling the infestation, while the cost of removing the wilding pines rises by 30% per year. The Trust is hoping to secure a small portion of the International Visitor Conservation and Tourism Levy to fund the eradication programme, so avoiding any additional burden on the taxpayer. The Government recently raised the levy 200% to $100.Oswald calculates that $8 of the levy would be enough to finance their project.