A Southland pest control group fears 18 years of work could be in jeopardy amid difficult conditions.

Since 2006, Mid Dome Wilding Trees Charitable Trust has worked to cull rogue pines from over 40,000 ha of land east of the Mataura River.

But funding had become increasingly difficult to obtain, and the once $5.5 million operation was now operating on a fraction of its budget.

Trust chair Ali Ballantine told Environment Southland on Friday that her group was beginning to feel the pinch.

LINZ was set to cut its $100,000 per annum funding from next financial year, and DoC had reduced its funding over 12 years from $300,000 per annum to just $50,000.

“Our programme area and surrounding landowners are now also facing wilding spread infestation from a growing number of carbon and productive Douglas fir plantations on nearby high and windy seed takeoff sites,” Ballantine said.

“All our good work is at risk.”

The submission prepared by the trust for council’s long term plan hearing said wilding trees were widely regarded as the country’s worst weed problem.

They currently affected over 2 million ha of land which would increase to 25 per cent of the country’s total land area if left unchecked.

Southland was highlighted as a significantly affected area.

The trust believed the council had historic responsibility for the issue due to the Catchment Board instigating plantings at Mid Dome between the 1960s and 1980s.

Ballantine said it was time for the council to boost its annual funding of $50,000 — which had remained stagnant for 18 years — to “at least” $80,000 per year.

Proposed new capital-value based Biosecuirty and Biodiversity rates were a good idea, she said, with the trust keen to receive the income from landowners within the programme area.

“If we hadn’t had the programme in place since 2006, then all the land as far as West Otago would now be infested, because you have a bunny hop effect,” Ballantine said.

"We think we've done a pretty good job of stopping that spread. Most of seed rain now would come within our programme area."

The trust’s review of the Mid Dome Wilding Tree Strategy last year showed approximately $20 million had been spent to date.

It concluded the programme was halfway towards its goal of completing works by 2034.

Ballantine has previously served on Environment Southland as a councillor and chair.

LDR is local body journalism co-funded by RNZ and NZ On Air