New Zealand has suffered a dramatic decline in native biodiversity which a University of Canterbury researcher has called the most pervasive environmental issue facing the country. Many of the issues associated with New Zealand’s declining biodiversity have close links to the loss and clearance of native forests.
UC forestry researcher Adam Forbes says due to the pressures of land development, native forests have suffered most heavily from clearance to the point where only one quarter of its pre-human extent remains. He wants to see if native forests can be restored within unwanted pine plantations.
“While about a third of New Zealand’s land area lies within the public conservation estate, much of this is located in inland mountain areas. It appears that reliance on conservation land alone is an inadequate conservation strategy.
“Increasing emphasis is being placed on the management of production landscapes for the maintenance of biodiversity with forestry plantations covering almost seven percent of the country.
“While most plantations are harvested on regular 30-year cycles some pine forests, because of their location or wishes of their owners, are unlikely to ever be harvested.
“These plantation areas provide a chance to restore native forests. But this opportunity is poorly understood and needs further research,’’ Forbes says.
He is researching under supervision from Professor David Norton, how native forest plants establish and succeed in an existing pine plantation. With no clear-fell harvesting and with sufficient time, a native forest can be developed and returned back to how the land looked 150 years ago. Forbes is looking at ways in which the growth of a native forest can be accelerated.
“There is a possibility that increasing the amount of light that reaches the forest floor by removing some canopy, and thinning out plants such as tree ferns that cause heavy shade on the plantation forest floor, will help exotic plantations become forests dominated by native plants more quickly.
“I am also interested in how a native forest grown from an exotic plantation forest can capture atmospheric carbon in the long term.
“Another option, and one with a potential financial gain, is the possibility of using the sheltered conditions within an exotic plantation to raise native trees for later timber harvest,” Forbes says.
The UC research project will be conducted in pine forests within the central North Island and Marlborough.