Friday, December 8, 2023

We’re buying our own wood back

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Technology developed by the New Zealand forestry sector more than 20 years ago and now used overseas could still offer some value-add options for Kiwi foresters today. Richard Rennie spoke to industry experts on how acetylising wood processing technology can turn pine into a high-value building product.
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A British firm is using a process developed in New Zealand to turn pine logs into high-value building timber then selling it back to Kiwis.

The fast-growing NZ pines are among the most suitable to be turned into high-value building material that can be used in place of hard woods by the acetylation process.

The British firm Accsys uses that process, partially developed in NZ by Scion predecessor the NZ Forest Research Institute, and bought by Accsys in 2006. The process alters molecules in the wood, modifying its physical properties to protect the timber from wood-eating insects and organisms without the use of the usual toxic preservatives.

It is known by its trademark, Accoya. 

The sale enabled the technology to be scaled up from its initial pilot plant plan that wasn’t built in NZ at the time. The technology was touted as a method to create a hardwood type wood as an alternative to harvesting endangered tropical hardwood trees.

Today the attractive wood product has applications for decorative building finishes but also forms the basis for weather-proof, leak-proof core construction material. It is also used for decking, window frames and even to line canals.

Forest Growers Research chief executive Russell Dale laments the loss of the technology. 

He believes there could still be potential for such a plant to be developed here, given the demand for the product and the value-added margins embedded in it.

“You are taking pruned logs at $180-$200 a tonne and converting them to a product valued at $3000-$4000 a tonne. It sounds like a good option.” 

NZ pine is felled, sawn, dried, shipped to Europe and processed as Accoya only to be shipped back here as high-value building material.

However, Dale is also realistic about the economics of long-term forestry plantings in NZ.

“If you went that way you rely on pruned logs to supply the plant and owners still have to make that significant decision about pruning in the hope there will be a market to pay the premium for that cost in 25-30 years’ time.”

Most big central North Island forestry operators have now chosen to cease pruning, opting for the industrial log market in China rather than incur the higher pruning costs. 

But the slide in log prices last year and again because of covid-19 has exposed how vulnerable NZ is to such a market.

Dale said for many smaller farm forestry owners pruning logs to supply an Accoya type plant is quite feasible. It is a way to hedge their bets against another slide in log values. Premiums for pruned logs run at about $60-$70 extra a tonne over unpruned.

Long-time farm forester Dennis Hocking said the technology ticks the boxes for its non-toxic, sustainable, value-added opportunities.

“NZ is also one of the very few places in the world where we do prune our pines. Thanks to our shorter growing time the return is always sooner than you would get in the northern hemisphere forests.” 

He suspects having a plant in NZ with the technology might be unlikely but there could be more opportunity to expand the supply NZ delivers to the European company producing Accoya.

“No doubt, pruning is labour intensive but it could also prove a worthwhile investment and employment source in these forests in coming years.”

His own operation is 50:50 forestry to farm and he credits the higher-value pruned harvest from his forestry operation for keeping the operation viable and profitable.

Wood Processors and Manufacturers chief executive Jon Tanner said certainty of supply and quality are critical for providing the feedstock to a capital-intensive acetylising plant. 

“One of the problems in NZ is this is a long-run business but most forest estate is owned privately. 

“This is unlike in Europe where government ownership lends more longer-term certainty and therefore underpins investment. Even pension funds here which we thought would provide that longer-term view are now reconsidering their investments in forestry after only seven years.”

Dale said it is a tragedy the technology developed here in NZ was not picked up at the time.

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