Ancient forest podocarp trees victim of erosion
An ancient forest with a lineage that stretches back to when New Zealand was part of the supercontinent Gondwana has been losing trees to erosion for years.
Podocarp trees at Marlborough’s Onamalutu Scenic Reserve have been lying in the O¯ hinemahuta River since July, but they are just the latest to fall victim to the riverbank’s erosion.
Emails seen by Stuff show the Department of Conservation was looking into fallen trees in the reserve in 2018, as a result of flood events ‘‘over the last couple of years’’.
But people who live beside or visit the forest frequently say the trees have been falling over for longer than that. DOC has confirmed it is now working on a longer term solution.
Ma¯ori carver Andrew MacDonald spent much of his childhood playing at the Onamalutu Reserve, about 40km west of Blenheim.
He explained how, back in 2018, he asked if he could have fallen logs for carving. DOC told him the trees were the council’s responsibility once they fell into the river. The logs were actually still DOC’s responsibility, but it needed a resource consent from the council.
So this time, when he found more trees in the river, MacDonald approached the council for consent in November last year, and was told it would cost $1000 with no guarantee his application would be successful. MacDonald decided against the application.
DOC South Marlborough operations manager Phil Bradfield said the riverbank erosion accelerated around the middle of last year when trees fell into the river, and erosion had occurred to a lesser extent before that.
University of Otago botany associate professor Dr David Orlovich said podocarps were an ancient group of trees and shrubs that dated back to Gondwana, a supercontinent that existed from about 550 million years ago.
‘‘The podocarps are a really unique feature of the southern hemisphere flora and New Zealand species are a very important part of this. The threat of erosion is a major issue for these local populations.’’