Greatest Hits 4 – Getting Technical: Stable Isotope Analysis, Part 2

Chris Knowles of Oregon State University and I got into some SERIOUS chemistry last week. Let’s see how it applies to the wood industry now.

Chris, you gave us a chemistry lesson last week. How do we USE this stable isotope analysis in the real world?

Among other uses, stable isotope analysis has a relatively long history of use for dating materials. Carbon dating provides an estimation of generally ±50 years for samples less than about 10,000 years old. However, the older the material, the less accurate the estimation will be. This estimate is based on a number of assumptions that may or may not be accurate. The bottom line is that this type of analysis will not identify the exact age of any material. It will only provide an estimate.

More recently, scientists have been exploring the potential to use the natural variability in stable isotopes by region to determine geographic origin of natural materials, including wood products. While the chemical analysis has a long history of use in other applications, the applications for tracking geographic origin of wood are still in their infancy.

How accurate is stable isotope analysis?

Several research papers I’ve read on this topic indicate that origin can be determined at a regional level with 70-90% accuracy at a regional level in some species. However the technique has not proven effective at differentiating across political boundaries to this date. Carbon on one side of a state line is pretty much the same as that a few feet across the border.

Research in South America has shown the potential to identify origin within approximately 100 miles in some tropical hardwood species, but that said, it is important to know that this has not been tested across very many species. There are far more unknowns than there are knowns at this point in time…

As the science currently stands, stable isotope analysis is not the silver bullet that will allow for accurate identification of the origin for wood products. There is still more research that needs to be done before the technology can be applied in that way.

What is the future of stable isotope analysis for tracking wood origin?

The future is yet to be seen. I think there is some potential to improve the accuracy of the technology significantly through more research. As I mentioned previously, the research on this application for the technology is still in very early stages. In order for it to be a useful tool in accurately tracking the origin of timber products we need to develop accurate and robust maps of the ratios of stable isotopes across the forested landscapes of the world. Since each species varies, the information would need to be collected for each of the commercially important species across it’s native and planted ranges. This information can then serve as a basis against which future stable isotope analysis results can be compared to. The challenge is this research will take many years and a tremendous amount of money to complete.

Once a robust and accurate database has been developed, I think there is some real potential in this technology. Previous research has shown that the accuracy of tracking origin is dramatically improved by using a combination of elements impacted by the environmental conditions (i.e., hydrogen, oxygen, nitrogen, sulfur) and elements impacted by the geological conditions of the site (i.e., iron, copper, zinc). In the future I think the potential exists for this technology to be utilized to reliably track the origin of some wood species.

Is it worth it?

It can be. The good thing about this type of science, both the DNA and the stable isotope analysis, is that they can’t really be falsified. As many of the environmental groups say, it would be a fact based condition, not a document based system. It will eliminate a lot doubt in the consumer’s mind. It also can work on material in most any form and age. We could do a lot of interesting tracking with this type of work.

The negative of course is the money—I don’t think this is feasible for every load of timber, much less value added products, produced anywhere in the world to be tracked like this. It will lead to further discrimination against some developing nations who can’t afford this—and those are the nations that need a healthy forest industry more than any others. As you know, a healthy forest industry leads to a healthy forest and if those countries are marginalized out of the market because of costs, they’ll just burn the forests and use the land for something else.

So Chris, will you come back and talk DNA sometime?

If people want more hard science, I’ll do my best!   In the meantime, if people want more info, they can go to these pages:

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