Most New Zealanders do not realise the threat to the environment and the economy posed by wilding conifers, Environment Southland chairman Ali Timms says.
The country was at a ‘‘tipping point'', she said, and more money was needed to control and eradicate the pest trees.
‘‘This is a classic weed issue. The cheapest time to do any sort of weed control is now.''Wilding conifers spread naturally and established themselves on pasture land and high slopes, Ms Timms said.
Rather than growing into harvestable timber, most became ‘‘scrubby bush which out-competes everything else'', she said. They also consumed water which could be used elsewhere and were a fire risk.
In December, 2014, the New Zealand Wilding Conifer Management Strategy was released - the result of co-operation between many parties, including the Ministry for Primary Industries (MPI), Department of Conservation (Doc), regional and district councils, and the New Zealand Forest Owners Association.
Last week, Local Government New Zealand (LGNZ) called on the Government and others to do more.
The issue was now so severe New Zealand could not afford any further delay in efforts to ‘‘tackle the relentless spread of the invasive trees'', LGNZ regional sector chairman and Otago Regional Council chairman Stephen Woodhead said.
Wilding conifers occupied around 1.8 million ha, nearly 6% of New Zealand's land area, he said.
While the problem was at its worst in the South, particularly Otago, Marlborough, Canterbury, Queenstown and Southland, the trees were also spreading through areas of the North Island, such as the central plateau. The potential economic impact was estimated at $1.2billion over 20 years.
‘‘If we don't mount a co-ordinated control effort now, there will be devastating long-term impacts for New Zealand's environment and economy,'' he said.
The estimated cost of a co-ordinated effort over a 15-year period was $160million-$180million, and any delay would increase control costs exponentially by $30million-$50million a year, he said.
Ms Timms has been involved with wilding conifer control on Mid Dome, Northern Southland, for the past 15 years. A trust was formed in 2008 to lobby for funding and co-ordinate control work.
Since 1993, $7.1million had been spent there, she said, including a Government grant of $1.2million three years ago.
While some progress had been made, more funding was needed, Ms Timms said.
‘‘Now we at last have a new formula of helicopter boom foliar spray available we have a clear way forward. We just need more money to be able to do the spraying. We don't want to see our good work go backwards.''
An MPI spokesman said more than $5.1million was invested every year by central Government with control work largely managed by Doc, supported by Land Information New Zealand and the New Zealand Defence Force.
MPI had also contributed $600,000 to two research projects to improve knowledge on the prevention and control of wilding conifers, he said.
