Department of Conservation officers in New Zealand thought they’d walked into the original Jack and the Beanstalk story when they came across a massive feral kiwifruit vine strangling the forest canopy in an East Coast reserve on the North Island.
In what could have been a scene from a Peter Jackson set, they discovered a huge vine running rampant, reaching 24 metres up into a Pukatea canopy tree in the Rakaukaka scenic reserve near Gisborne.
Technical Support Officer with the East Coast Hawke’s Bay Conservancy Don McLean said the feral vine was well established and into the forest canopy, smothering the native vegetation in the semi coastal kahikatea-broadleaved forest.
“This feral kiwifruit vine had similar potential damage for lowland remnant forest patches as we see with vines such as old man’s beard,“ Mr McLean said.
The 5.7 hectare DOC Rakaukaka reserve is a semi coastal forest patch, and is surrounded by orchards. It is believed the feral vine was an orchard escape.
Mr McLean said feral vines smother forest margins and forest regrowth, reducing light, particularly in canopy gaps.
“This prevents the regeneration of native vegetation, and in turn, destroys food sources for birds, insects and other species.
“The weight of the vines can also end up breaking the branches of the trees they hang on.”
A spokesman for Weedbusters, the national inter-agency weeds education and awareness programme, Keith Briden, said the reserve was the only one in the Gisborne area known to have feral kiwifruit vines.
“This vine was probably the highest a feral kiwifruit vine has been found growing in the canopy of native forest in New Zealand.”
Mr Briden said that when kiwifruit vines went feral, they became aggressive environmental weeds.
“We don’t want them in our forests,” he said.
Contractors have been brought in to help clear the giant kiwi fruit vine from the reserve.
Mr Briden said regular weed surveillance would be undertaken to ensure the vine did not grow back again, and that no new vines established.
“Feral kiwifruit have also been a concern in Bay of Plenty gullies in recent years, and the kiwifruit industry has been working with Environment Bay of Plenty to contain the vines,” Mr Briden said.
Environment Bay of Plenty plant pest coordinator John Mather said the control of wild kiwifruit in the Bay of Plenty was proceeding very well.
“Much of our current control work is with younger vines, less than seven years old”
Mr Mather said wild kiwifruit could be very long lived. One cultivated vine in Korea is reported to be 600 years old. A single 30-year-old vine can smother 1000 square metres of scrub and young bush.