A former New Zealander of the Year is taking a swing at the government's Billion Trees Programme, saying it's going off track.
Two thirds of the trees funded through the $240 million grants programme are supposed to be natives.
But anthropologist and environmentalist Dame Anne Salmond said foresters were overwhelmingly using this fund to plant exotic pine trees.
But the minister responsible Shane Jones said the native planting threshold will be met.
The billion trees programme is the brainchild of New Zealand First - with an ambitious target of planting a billion trees by 2028.
The majority of the funding is supposed to be put into planting natives.
But Dame Anne is concerned things are going off track.
"Well I think the billion trees policy is great and I think the promise to plant two thirds natives was a good one but that's not what's happening. From everything that's being said it's at the moment 88 percent pine trees and 12 percent natives."
Dame Anne said other countries were doing their own version of the Billion Tree Programme, including China and Germany, and they were taking a 'close to nature' approach ...where forestry was designed around its environment and often included large numbers of natives.
"The whole policy is intended to tackle climate change and there's a global consensus that plantation forests like pinus radiata for example are not the way to do this but natural forests sequester according to scientific articles recently published - 40 times more carbon than plantation forests which are felled of course."
Dame Anne said that focusing on exotic tree species - such as pine - could also lead to more problems down the track.
"It's not only the case that we are investing in pine trees instead of natives, but the question is are we going to be able to sell them. The stated intent of two-thirds natives should be adhered to and I don't know how they've got to a situation where they've got 88 percent in pine trees. Obviously something is going wrong with the way that policy is being executed."
But Forestry Minister Shane Jones defended the programme in Christchurch today.
He was in the city to announce funding to help two native planting and restoration projects in Canterbury.
"I don't want to say anything deprecatory of a personal nature about a famous New Zealander and indeed my old lecturer in 1978 but I think unfortunately her article represents a fresh wave of confusion. There are a whole host of waves both political, ideological, washing along the political seashore that I occupy and unfortunately her facts are not accurate."
Mr Jones is confident that the native tree threshold will be met, but said the mood of the private market had an impact on how quickly it was reached.
"We are expanding the size of the nation's lung to enable us to build a bigger platform for sequestration to cope with the climate change journey. Sure I have a lot of affection for native trees but the reality is people spending their own money will make a choice to favour exotics and the Crown can fill the gap with natives.
"It is taking a lot longer for landowners to step up to the plate although they have a larger grant entitlement to plant totora, puriri, manuka, and most of the exotics are being spent to effect catchment outcomes, improve soil consolidation and very quickly turn around negative environmental outcomes."
The government hopes to reach its billion tree target by 2028 - Mr Jones said they should be planting 100 million a year from 2020.