Plans to transition radiata to natives look like greenwashing

Dave Read has farmed in the Wairoa district for 35 years and has researched the effects of NZ climate policy for many years. 

Ongoing concern about climate change has fuelled debate about the part carbon sequestration might play in reducing New Zealand’s net carbon emissions. 

Land-use change is happening at pace in New Zealand. Companies plant forests, and then earn income by selling carbon credits through the Emissions Trading Scheme (ETS). 

Recently, some companies have claimed they will transition radiata forests to natives. They have already planted tens of thousands of hectares of land. Despite many people in these companies and some academics passionately believing radiata can transition to native forests, this looks a lot like greenwashing. 

Both images with this article are of 15-year-old radiata forests. The second one is a real forest owned by a company promoting transition forests. The first one is from a digitally constructed 100-year sequence in the same company’s advertising material. The stark difference between these two pictures should make us question whether “transition forest” claims are valid. This company was asked for comment, but declined to reply. 

Even with the present depressed price for carbon, forest owners can make huge returns by selling carbon credits to industries that pollute. 

Under the rules, owners of radiata forest that will be harvested can only claim the first 16 years of sequestration because this is the average carbon held by their forest over several harvest cycles. 

Radiata forest owners with a short-term outlook can make much more money by becoming a “permanent forest” under the ETS; they pledge never to harvest their trees. Under ETS rules, they can then continue to earn carbon credits as long as the forest is growing faster than trees are dying. For 70-90 years they can earn a lot, but after that the income ceases; the land can never be used for another purpose because the trees (and the carbon they contain) must be maintained in perpetuity. “Permanent” radiata forests have a high fire risk. As can be seen in the photo, they have a lot of dead wood due to minimal thinning and no pruning. 

The other problem with permanent radiata forests is they have a bad public image. The public would much rather see hills covered with green pasture or diverse native forests, or at the very least a real product such as timber being produced. 

Unfortunately, native forests are expensive to establish and they grow slowly, earning far fewer carbon credits than radiata in the short term. 

These are the social and economic forces that have led companies to spend tens of thousands of dollars promoting transition forests, which use radiata as a nurse crop for native trees. 

These companies use a management regime that will maximise revenue from carbon credits. They avoid any dip in earnings by thinning only a few trees. 

The early research behind the idea of radiata transitioning to natives was done under pine forests at Kaiangaroa. These forests were grown for timber at 300 trees a hectare, which allows some light to support ground cover. The bare carpet of needles seen in the picture is under a forest with over double this number of trees. 

The whole idea is dependent on nearby remnant bush providing a source of seed. Even for seeds dispersed by birds, 80-90 per cent of seed is dropped within 100m of the source. 

When there are no nearby seed sources, the owners propose making light wells and planting species that can withstand some browsing. This is because most new forests (unlike those at Kaiangaroa) are surrounded by farmland. They have high populations of goats and deer, which go out to feed on the surrounding pasture and return to the shelter of the forest. 

The model in the image gallery above shows the amount of carbon dioxide (CO2) the real forest is likely to store under the management proposed for transition to natives. Due to the effects of deer, goats and invasive weed species, it looks nothing like the computer-generated marketing images. Worse still, if we follow the modelling beyond 100 years, we see a false peak followed by a period in which dying radiata emit carbon. 

Note: At present, the Ministry for Primary Industries has look-up tables for natives for only their first 50 years of growth. This graph is based on numbers produced by NZ Forest Research Institute. A technical reviewer of this model stressed these sequestration numbers are very optimistic. 

Greenwashing is being used to persuade us to give social licence to forests that will still look like dark, gloomy radiata forests for the next 100 years or so. 

These “permanent forests” will leave a huge carbon liability for future generations. It would be easy for these companies to walk away at the false peak of storage with all their profits. Their legacy will be a further 100 years of carbon emissions that would need to be covered by carbon credits purchased by the taxpayer at huge expense.