Ms McDiarmid said converting forestry to make way for cows was a double whammy for the climate, as it destroyed forests and replaced them with dairy farming which was the most greenhouse gas intensive form of land use.
Agriculture was responsible for 49 per cent of New Zealand's greenhouse gas emissions.
This figure had increased by 15 per cent since 1990, and dairying was responsible for this increase.
Ms McDiarmid said that according to the Ministry of Agriculture and Forestry about 455,000ha of forestry land in New Zealand was at risk of being converted into pastoral use.
"This is nearly seven times the size of Lake Taupo."
Government figures also projected that the number of dairy cows in New Zealand would increase by up to 21 per cent by 2010.
"We can expect a corresponding increase in greenhouse gas emissions."
Landcorp Farming chief executive Chris Kelly , told the Herald Landcorp was contracted to lease and manage the land from the landowner Kiwi Forests Ltd, which was run by three Auckland businessman.
"We do not own the land or the trees."
The Aucklanders had decided to harvest 9000ha of the 24,000ha forest block.
Landcorp was contracted to manage the cleared land of which half would be used for dry stock and the rest converted to dairy.
"If we weren't doing it someone else would be."
Mr Kelly did not know what was planned for the remaining forest.
He said the trees planted by Greenpeace had been removed again soon after the volunteers left.
"The owners of the land have taken some action, the trees have gone and as I understand it are being donated to a local group."
Greenpeace communications manager Suzette Jackson said police had arrived mid-morning, and warned the volunteers against trespassing further.
"We left then because we weren't trying to get our team arrested, and we managed to plant all our trees.
"It's good to hear they're not going to go in and rip them out, that they will be able to be planted somewhere else," Ms Jackson said.
- NZPA
