If your Christmas tree is browning up at the edges and it's time for it to go, the Department of Conservation (DoC) wants you to think carefully about how you get rid of it.
Wilding pines spread near Lake Pukaki in the Mackenzie Basin. Photo: MPI
New Zealand has a serious problem with wilding pines, which a number of government agencies, along with community groups, are trying to get on top of.
Wilding pines are considered invasive weeds and the worst areas of infestation are generally in the high country - such as the central plateau in the North Island and the Mackenzie Country and Wakatipu Basin in the south.
DoC technical advisor Keith Briden said about 6 percent of New Zealand was affected by wilding pines - a problem expected to treble within about 20 years that problem will be three times as bad and up to 20 percent of the New Zealand land area will be affected."
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The trees can have up to 17,000 viable seeds and are capable of spreading 20km.
The young trees spread in tussock land around Queenstown. Photo: Scion
Mr Briden said some of New Zealand's most famous tourist landscapes would be completely transformed into wilding pine forests if action was not taken. Once they took hold, they were expensive to eradicate so it was far better to control them when they were small trees, before they started seeding.
The pines made a nice Christmas tree but people needed to think about taking and disposing of them, he said.
"What we don't want is people taking those trees off the site, putting them on their roof racks or on their trailers and then carting those trees round. It only takes a few seeds to come out and form a new infestation.
"And the other thing we don't want them to do is when they finish with their Christmas trees, at the end of the season, is to take them out into the countryside or onto a DoC reserve and dump them."
Community groups fight back
In Queenstown, the Wakatipu Wilding Conifer Control Group works hard to try and control the spread of wilding pines. The community group is running an adopt-a-plot programme for people to adopt a bit of land and then clear it of any rogue trees.
Group chairman Peter Willsman said they actually encouraged people to take wildings as Christmas trees as a way of getting rid of them.
"There just so many thousands and thousands of wilding trees around this area that the more people take for Christmas trees, the better."
But he said he did not believe the ones taken for Christmas posed a risk.
"They would have to be very big to seed, and certainly if they were seeding we wouldn't want them to dump them anywhere, no. But seeding is from cones and you'd have to have quite a large tree to have cones on Douglas fir or most of the pinus species."
Wilding pines invade farmland on Molesworth Station. Photo: MPI
Toby Regan sells Christmas trees in Wellington's Aro Valley as part of fund raising for the local school, pre-school and community centre, where they offer an environmentally friendly disposal service for tree buyers.
"We have a recycling service so we'll get people to drop their trees off back to us and we'll mulch it, and give them back the mulch afterwards for their gardens - so that's one way of minimising the possible wilding trees growing."
'Useless trees'
The Ministry for Primary Industries takes a leading role in co-ordinating the fight against wilding pines in terms of pest management. Last year, it released a national strategy to deal with the pines.
The manager of its long-term management group, John Sanson, said public awareness was crucial.
"A lot of people will be driving around over the country over the summer holidays, and perhaps a lot of people would look out the car window and see some trees out on the landscape - and perhaps nor appreciate that in some cases those trees are wilding spread conifers.
"[They] might just be a few trees dotted across the landscape now but if we don't do something to remove those, in a few years they'll start to seed and, ultimately, in a decade or two become a very substantial forest of useless trees."
Mr Sanson said people needed to consider how they could become part of the fight against wilding pines.
Meanwhile, DoC has urged people getting rid of their Christmas trees to either take them to a landfill or cut them up and put them in their green bins.