Detecting Timber Faults at Scion

Scion researchers are unlocking the mysteries of what is going on inside trees and what it means for New Zealand’s wood products.   New technology is now letting scientists understand what is happening inside trees, and at a level which has never been possible in the past.

Previously trees were cored for information with a single core taken at breast height, or 1.4m above the ground. But the information which could be gained from this is like taking a soil sample from only one hole and using that across the whole farm to indicate soil fertility.

Now it’s possible to slice up a tree – a bit like slicing up a cucumber – into a series of discs for analysis. Scion researchers have developed new methods for analyzing information from these discs.

This work has been funded by Future Forests Research, a vehicle which combines government and industry funding. It is one of the core projects in a six-year programme of research.

Mike Riordan, Radiata Management Theme Leader from Future Forests Research says “These guys have come up with some clever and innovative solutions to problems that have beleaguered the industry.

The industry wants to produce timber which stays straight and doesn’t warp, and which performs to end user expectations. For example, this work will help to explain why one 4×2 will twist and cup, and others don’t.”

It’s estimated that each year downgrading of poor quality timber after milling and drying costs the industry millions of dollars per year. Up to 10% of timber is downgraded due to excessive distortion, which reduces returns and profitability for the sector.

The Wood Council of New Zealand, which is a pan-sector organization, has a strategic plan to grow the industry from $4.5 billion a year to $12 billion.

“To do that we have to better understand the wood resource that we currently grow and make sure that we send material to the most appropriate processing plants. This will help increase the proportion of our wood supply which is processed domestically, rather than going offshore,” Mike says.

The industry needs to be more internationally competitive by getting better recoveries of the timber it already mills. “And our end users need to know products will meet their performance expectations. This is important if we want to see more timber used in construction.”

The wood properties which are measured are:

1. Wood chemistry (galactan, which is a hemicellulose; glucose and lignin) using near infra-red spectroscopy. This is the same technology that is used in agribusiness applications such as in combine harvesters to look at the sugar and moisture content of the grain as it is harvested.

2. MFA – microfibril angle: the winding angle of cellulose chains around the cell wall. Low MFA levels mean the wood is very stiff. This uses an ultrasonic technique: the stiffer the wood, the faster the soundwaves move through it.

3. Density – this uses X-ray technology.

4. Spiral grain – this has been difficult and time consuming to measure up until now. In a kiwi “number 8” wire innovation, a Scion colleague butchered a flatbed scanner and put it back together to look at the spiral grain. This research is a world first.

Some of the trees tested have been sampled every 300mm, so have had up to 100 discs (or biscuits) cut from them. This level of resolution allows the researchers to measure the variation in wood properties at a scale that drives end product performance.

At present the methods are still at a prototype stage of development. However, a new $1million project is underway to create a robot to make an automated and integrated testing system to industrialise the process for a cost of $1000 a tree. This is expected to be completed by the middle of 2013.

The researchers want to understand the impacts of different genetics, of different management methods and different sites on the trees.

“If we can sample enough of these trees we can build up a picture and use it to predict what we will get from different combinations of genetics, management and areas of the country.”

They want to sample several thousand trees across all their trials in NZ to build up a picture of what is happening in the trees. Then they will be able to create models and maps of wood properties across different genetics, management methods and sites.

“From this we can predict the quality of timber that will come from the trees and can then direct them to the most appropriate end use. Wood processors will have improved confidence that the logs they are buying will yield the desired products, which will improve their bottom line.”

Mike says the work done to date has just started to give the industry insights into what is possible. It has also helped to better strengthen the forest to customer value chain. It’s a “plank to plant” idea.