Environment Canterbury has launched this season's campaign to control wilding conifers in the region with work focusing on the Waimakariri, Hurunui and Waitaki catchments.
Control in high country areas employs a practice called "skid-hopping" where helicopters take specialist contractors into more mountainous areas. Because the helicopters cannot land, chainsaw operators hop on and off the skids to cut down those hard-to-reach trees.
Wilding conifers, or 'weed trees', are self sown trees that have spread from research plots, lakeside amenity plantings and farm plantations. They threaten Canterbury’s high country landscapes, tussock grasslands and pasture productivity by competing aggressively for light and space.
Environment Canterbury biosecurity manager Graham Sullivan says that even at eight years old, some species are able to produce seed. Control then becomes a long-term problem as new seedlings will continue to spring up for years to come.
"Prevention is better than the cure - the amount of work and the cost involved increases dramatically once trees exceed 50mm at the base. It’s important that we deal to these pest trees before they can take advantage of summer growth conditions and produce a new crop of seed," says Graham Sullivan.
Eugenie Sage, Environment Canterbury pest management committee chair, says that $226,000 of ratepayers' money is spent annually on controlling wilding conifers and land-occupiers spend many times that on the problem.
"Community initiatives such as those carried out by the Waimakariri Ecological Landscape Restoration Alliance (WELRA) and Lake Ohau Conservation Trust are also critical in tackling this needle-clad invader," says Cr Sage.
"Environment Canterbury's Resource Care team organises groups of willing volunteers, armed with pruning saws or loppers to deal to trees in open country while they are still small. Every year for the last 13 years, over 200 volunteers have come forward to help. That energy and commitment is hugely important. Without their assistance, areas between Porters Pass and Lake Lyndon or Cave Stream could now be covered by weed trees," she says.
"Canterbury has many special habitats that are worth protecting. Wilding conifers require sustained control on many fronts over many years. The regional council is in this battle for the long haul."
For information about the wilding conifers control programme, visit www.ecan.govt.nz/wildingconifers or call Graham Sullivan on 03 687 7835.
For further information: Environment Canterbury Pest Management Committee Chair Councillor Eugenie Sage, 021 155 3937.