Progress on tree removal on agenda

WITH phase one of a national wilding control programme in its third and final year and planning for phase two of the programme under way, Omarama will host the NZ Wilding Conifer Conference next week.

Ministry for Primary Industries wilding conifer control programme manager Sherman Smith said the trees were the ‘‘No 1 plant pest’’ in New Zealand.

The programme would continue to contain and progressively remove the windspread offspring of about 10 tree species, including Douglas fir and Pinus radiata, from vulnerable landscapes, he said.

‘‘When they grow in the wrong place, they outcompete native species, drain valuable water resources, reduce productive farmland, harbour pests and create a fire hazard,’’ Mr Smith said. ‘‘They also irreversibly change the iconic landscapes and vistas such as those Central Otago is famed for.

‘‘We know that the cost of control operations increases significantly over time if wildings are left to spread, so early intervention is the most costeffective option. For example, treating light infestations can cost as little as $20 per hectare to control, versus as much as $2000 to treat denser infestations.’’

Before control started, the trees were spreading at a rate of about 90,000ha a year, and with control under way they still cover about 5% of the landscape.

If left to spread unchecked, it was estimated the plants would cover 20% of New Zealand’s total land area — or 5,400,000ha — by 2030.

The national wilding conifer control programme, led by the Ministry for Primary Industries and supported by the Department of Conservation, Land Information New Zealand, the New Zealand Defence Force, and regional and district councils, is supported by Crown research agencies and groups such as the New Zealand Forest Owners’ Association and Federated Farmers.

A variety of community groups and trusts also work in partnership with the programme.

National Wilding Conifer Group coordinator Rowan Sprague said the annual conference would highlight the success achieved and the challenges that remain in the Mackenzie Basin.

A conference field trip stopping at Peters Lookout, Irishman Creek Station and Mt Cook Station would focus on the work already done and the challenges remaining.

The New Zealand Emissions Trading Scheme, management strategies for Pukaki Downs and Glentanner and a collaborative project with the Mackenzie Basin Wilding Tree Trust, Environment Canterbury, the Ministry for Primary Industries, the Department of Conservation, Land Information New Zealand and landowners will all be discussed during the conference.