Tuesday, July 22, 2014
Why all the rebranding? The Mississippi Experience
Last week we looked at how Oregon State University changed because it felt its customers, the students, wanted a different product. This week, David Jones of Mississippi State talks about how a changing world led to changes in its approach:
Unlike Oregon State, our undergraduate program completely disappeared early on in the 2000’s. It has been somewhat maintained through a concentration in forestry and through a graduate-level program. What we found was there was a great deal of confusion about what the “Forest Products Department” did or how it fit with the mission of the university. To limit confusion and align the department with current funding from grants, we changed our name to the “Department of Sustainable Bioproducts.” This name encompasses the many different facets that we now cover, including lumber, composites, environmental research and biological research.
Of course, changing the name is only the first step in the process for us. Currently we are working on rebuilding an undergraduate curriculum to better cover the changing face of bioproducts. This is a difficult process, as all coursework must be carefully decided upon to make sure it will prepare students for life after the university. This includes adding courses on other materials, such as kenaf, corn stover and other plant materials. There has not been a move away from forest products, but an addition of other plant materials that have been utilized along with wood for many decades.
While the undergraduate program was in decline and eventually disappeared, we continued to provide support and outreach to the industry. This includes providing research and development for new products when it was too costly for the manufacturer. This included research in agricultural fibers as additives to traditional wood based materials. The bottom line is that the world’s view (and use) of bioproducts has expanded far beyond wood, and we’ve expanded our reach in response.
Tuesday, July 15, 2014
Why All the Rebranding? The Oregon State Experience
Most of the traditional wood science programs in the U.S. have recently changed the names of their degree programs, their department names, or both. Departments of “forest products” have become departments of “sustainable biomaterials,” “sustainable bioproducts,” or perhaps “bioproducts and biosystems engineering.” Wood science and wood technology degrees have become degrees in renewable materials and sustainable biomaterials. Some within the industry have been critical of the redesigns, especially when it comes to undergraduate curricula that they perceive to be watered down from the “good old days” when they were students.
What has driven the change? I asked two universities to comment on this. First up, we have a look at the Oregon Experience by Chris Knowles:
At OSU, the primary motivation has been centered on attracting students. At the depth of the Great Recession (the recent one) we dropped to 17 total undergraduate students in our Wood Technology program, which equated to less than two students per faculty member. At that level, the university begins to question the point of maintaining a program at all!
Clearly we needed to do something different, given the changes taking place in our customer base (students), not to mention the pressure coming from the university administration. In a true, market-oriented approach, we went to our customers to learn what they want in a degree and in a career. We conducted focus groups with high school seniors and with current OSU freshmen. The key takeaways we learned in the process were that the impacts of the recession were top-of-mind for many students and each person often knew one or more people who lost their job during the recession. Therefore, the students were looking for an education that would provide them with broad possibilities and flexibility. “Wood Technology” was not something they saw as providing this.
As part of the focus group process, students voted on titles of a degree program that they would find appealing. They had multiple choices; among them was “wood technology” and “renewable materials.” Renewable Materials was the descriptor that was most popular among the focus group participants, while wood technology was dead last. It shouldn’t be too hard to guess what degree we now offer.
The name change was just the beginning of our efforts. We also had in-depth conversations with other stakeholder groups including the potential employers of the graduates we produce. The faculty then held a retreat to determine how the old wood technology curriculum would need to be changed in order to deliver a degree program that would live up to the name “renewable materials” and meet the needs of our stakeholders. A new curriculum was developed that included deleting some old courses (such as “Introduction to Wood Science”), creating some new courses (such as “Renewable Materials for a Green Planet”) and modifying the content in other courses (such as “Manufacturing with Renewable Materials,” which was previously called “Primary Manufacturing”).
Additionally, we modified the delivery method for some content. For example, the Primary, Secondary, and Composites Manufacturing courses each had lab sessions where students would tour relevant forest industry manufacturing facilities. The new manufacturing courses, “Manufacturing with Renewable Materials I and II,” do not have lab sessions. The students now take a new course called “Renewable Materials Manufacturing Experience” where the students tour a wide variety of manufacturing facilities in one intensive week-long course. The end product is a degree program that provides students with a blend of technical content and practical business and communication skills that we feel prepares students to enter the broad field of renewable materials.
The outcome of our efforts is that we now have over 60 undergraduates in our program. The makeup of those 60 is quite different than what we have had in the past. We have significantly more females in the program (nearly half) and many come from an urban background. We feel that these youngsters are exactly what are needed to help transition the forest industry into the growing bio-economy, shifting away from commodity products, and enhancing global competitiveness. The first students to complete the full curriculum graduated this year, so it is still too soon to see how this will play out with their employers. However, we expect the redesign will prove to be a valuable contribution to Oregon’s forest sector and the future competitiveness of its companies.
Tuesday, July 08, 2014
ILP Down Under, Part 2
We’re continuing our look at the ILP, which, as a refresher, is collectively two related bits of legislation: the Illegal Logging Prohibition Act 2012 and the Illegal Logging Prohibition Amendment Regulation 2013.
The Australian government has generally outlined a four-step due diligence process for importers and first-tier domestic producers.
1. Do “basic research.” This is to be done by the importer/processor to understand the risk level for a species and where it was harvested for their current or planned supply chain.
2. (Unlike Lacey), if the product is covered by a third-party system such as FSC, PEFC, or a recognized legality verification program (such as EU FLEGT licensing), that is considered sufficient demonstration of little or no risk to handle without further research or risk mitigation. If the product is not covered by a thiparty system, the company must determine risk using against four risk factors or use a Country Specific Guideline that Australian Government is currently preparing in collaboration with many other countries.
3. If the product is found to be low risk, then the company may consider their due diligence completed and the business can proceed.
4. If the product is found to be anything other than low risk, the company must take documented steps to mitigate that risk before continuing the business. The risk mitigation is not specific but must be "adequate and proportionate" to the risk.
The Country Specific Guidelines are a very interesting development. Meant to assist importers of wood harvested in those countries, they should provide quick shortcuts of what the exporting country regards as "legal timber". The first one produced is for the Solomon Islands. Other country guidelines will follow for Australia's major trading partners—not just countries that are regarded as not low risk, either.
Importers of these regulated timber products will also be required to make a declaration of compliance with the Regulation with Customs when they import. Unlike Lacey, however, this declaration will be just a yes/no type declaration and answering no will not result in goods being held up at the border. The compliance authority (Australian Department of Agriculture in this case) is likely to be following up those who answer no. Public advice from the Australian government is that for the first 18 months after Nov. 30, 2014, their emphasis will be on educating industry how to comply rather than trying to "catch out" businesses not complying.
Penalties are at the discretion of a court; the maximum penalties that may be applied currently are:
These go into play only if the importer of regulated timber product and their trade/action can be shown to have been negligent when importing illegally logged timber. These same maximum penalties apply if an importer or domestic processor “knowingly, intentionally or recklessly” imported or processed illegally logged timber.
- five years imprisonment, and/or
- $85,000 for an individual, and/or
- $425,000 for a corporation
- plus forfeiture of timber product / raw logs
The Australian Timber Industry has also been on the front lines in preparing for the Regulation. They have developed a range of tools, templates and additional detailed information about due diligence. Largely based on the tools and templates produced for European Timber Trade Federation as well as assorted U.S. sources, they have been modified for the Australian legislation. These are freely available to domestic and international companies.
The risk based approach of the Australian legislation means that exporters to Australia of products made from wood which is generally regarded as little or no risk, such as U.S. and Canada, shouldn’t have to do anything particularly onerous for their Australian customers to justify a low (or better) risk rating. However it's expected that Australian importers will take a while to understand the legislation and what information they need to ask (or not ask!) for. The good work of organizations such as AHEC for exporters to the EU in supplying a standardized form of information will greatly assist importers to Australia.
For more Australian Government information:
For more Australian industry timber due diligence information:
Tuesday, July 01, 2014
ILP Down Under, Part 1
We have “Lacey” and the folks Down Under have “ILP.” ILP is collectively two related bits of legislation: The first is the primary piece of legislation, the Illegal Logging Prohibition Act 2012, and the second is the subordinate Illegal Logging Prohibition Amendment Regulation 2013.
The coverage and focus of the two parts differ somewhat. All imports of products made of wood and Australian processors of raw logs are covered by the Act, while the Regulation only applies to importers of "Regulated Timber Products" as well as domestic processors of raw logs. (This list of "Regulated Timber Products" is almost identical to the Lacey list of products for which a declaration currently must be made—lumber, decking, flooring, pulp, paper, wood furniture, etc.) The Regulation begins to cover imports on Nov. 30, 2014.
While similar in principle to Lacey and the European Union's EUTR and with the same basic goal—eliminate illegal wood in the supply chain—there are quite a few differences in practice, of course. Naturally, this is important to American exporters; however, importers may find a bit of research into the legislation useful as well, as Australia has put tremendous emphasis on due diligence. And to support those businesses affected, the government and the Australian timber industry have both developed a number of tools and guidelines to help. These tools can be accessed by anyone from two websites (listed below) and may provide companies with ideas that will help them comply with either/both Lacey and the EUTR.
ILP is different from Lacey (but similar to the EUTR) in the fact that responsibility stops at the entry into the general marketplace. Only the actual importer or the domestic processor (e.g. sawmiller) has full liability. Those downstream that do not directly import timber or process domestic raw logs are not covered—unlike Lacey, where American distributors and retailers are responsible for all material they trade in, domestic and imported.
Another difference is that in Australia there is a two-tier prohibition system. Under the Act (the primary part), the importer or domestic producer can be prosecuted based on if they “knowingly, intentionally or recklessly” imported or processed illegally logged timber. Under the Regulation, the importer can be prosecuted based on if they imported illegally logged timber and it can be proven that they were "negligent." Note that both emphasize a deliberate misconduct or a clear failure on the part of the importer. This is a significant difference from Lacey, where an importer can act aggressively in good faith to eliminate illegal material and still be prosecuted for some action by someone earlier in the supply chain over which they had no control and no knowledge.
The program, like the EUTR, requires companies to make a real effort. Importers of these regulated timber products, as well as domestic processors, also have to undertake a process of due diligence to minimize the risk that the goods they handle could have been illegally harvested. Stephen Mitchell of the Timber Development Association stated that “If a company is found to have illegally harvested timber in their possession, but can also demonstrate having in place a sound due-diligence program in an attempt to avoid such a situation, it is hard to see any prosecution action being undertaken.”
That makes two immediate differences from Lacey—first the focus here is specific to illegally harvested material, while Lacey potentially covers any possible related infraction. (For example, the second Gibson investigation was related to HTS codes, not to the potential illegal harvest of the wood in question.) The second difference is the requirement that a company has a due-diligence program. For Lacey, having a good due-diligence program will obviously help if there is an enforcement action and be taken into consideration by the government, but it is not protection against enforcement, nor is it mandated by the statute. (Of course it’s just plain common sense and good corporate behavior to have one, even if it’s not specifically mandated!)
Next week we’ll look at how the Australian government plans to enforce the new requirements. In the meantime:
For more Australian government information:
For more Australian industry timber due diligence information:
Tuesday, June 24, 2014
Russian Woods to Be Listed on CITES, Part 2
After learning that Mongolian oak and Manchurian ash will be listed in Appendix III of CITES (more on what CITES is here), I contacted the U.S. government’s Fish and Wildlife Service for more information on conducting proper and legal trade in these woods. They immediately responded with the following advice and information, which I have bulleted here to make it easy for everyone to follow:
- The two Russian timber species listed are:
- Quercus mongolica (Oak)
- Fraxinus mandshurica (Ash)
- Both listings were annotated with Annotation #5, which means that only logs, sawn wood and veneer sheets are covered under the listing
- The listing will become effective on June 24, 2014. Production exported prior to that date is not covered.
- Because the Russian Federation is the listing country, shipments of logs, sawn wood, and veneer sheets of these two species from the Russian Federation must be accompanied by CITES export permits. Further:
- Exports of logs, sawn wood, and veneer sheets of these two species from all other countries, including where the species are not native but may be grown in plantations, must be accompanied by CITES Certificates of Origin.
- All re-exports of logs, sawn wood, and veneer sheets of these two species, regardless of country of origin, must be accompanied by CITES re-export certificates.
- Finished products, such as furniture, of these two species are not subject to CITES requirements and therefore do not have to be accompanied by CITES documents when traded internationally.
- CITES-listed plants and plant products must enter the United States through a "Designated Port." If you have questions about designated ports, please go here for more information.
- U.S. CITES interagency partners, including both USDA-APHIS and CBP, are aware of these new listings. Port inspectors should be aware of the new listings and ready to implement them for all shipments entering the United States on or after June 24.
- For permits and more information, go here.
Tuesday, June 17, 2014
Russian Woods to Be Listed on CITES, Part 1
A Russian oak tree. (Courtesy of Brian Milakovsky/WWF-Russia)
Last week our Alphabet Soup series defined CITES. CITES is in the news for the flooring industry right now because Mongolian oak and Manchurian ash from Russia (and other species) will be added to CITES listings at the end of the month. I talked to Linda K. Walker, Director, Global Forest & Trade Network-North America about these additions:
Linda, how did these species get added?
Russia's Ministry of Natural Resources and Ecology pushed for inclusion of Mongolian oak (Quercus mongolica) and Manchurian ash (Fraxinus mandshurica) in Appendix III of CITES due to the well-documented levels of illegal logging of these species in the Russian Far East. For example, WWF Russia conducted a comparative analysis of the volume of Mongolian oak legally permitted for harvest in the Russian Far East in 2010 with the "roundwood equivalent" of the volume of exported oak logs, boards and veneer. It revealed that 2 times more oak was logged for export than was permitted by law.
That’s compelling evidence. Once the listing goes active, what will happen?
According to our WWF-Russia colleagues, inclusion of oak and ash in Appendix III means that before companies can export these species from the Russian Federation, they will have to present evidence of the legal origin of the timber to the Russian Environmental Monitoring Agency (Rosprirodnadzor). On the basis of that evidence, the agency will decide whether or not to issue an export permit.
The necessity to present such a document will greatly complicate the export of Mongolian oak and Manchurian ash that was logged without any authorization, which should in turn reduce the illegal harvesting. However, the system for collection and checking of documents is still being developed.
So what should buyers look for?
Buyers should ensure that they’ve exercised the due care required of them by laws such as the Lacey Act. Based on what we know about the reliability of documentation for these particular species at this point, we think “due care” here means not just taking documentation at face value, but also analyzing these documents, if possible with the participation of local experts, to ensure that the timber harvest they authorize could really have been the source of the imported products. There are several official documents we expect exporters to offer as documentation:
1) A "forest declaration," the document which determines the location, volume and species composition of timber harvest for forest leaseholders.
2) A purchase contract for conducting of "intermediate logging" (various forms of thinning, intended to improve growing conditions for the remaining trees) or "sanitary logging" (intended to remove sick and dying trees to improve the health and rigor of the stand) in forests not given out under lease.
Examples of the documents mentioned above and others can be found in WWF-Russia’s “Keep it Legal” guide.
However, WWF-Russia believes that great care must be taken to develop this system so that fraudulent “multiple use” of logging authorization documents is prevented.
What is “multiple use?”
There is a limited quantity of such authorizing documents produced in a year, and in theory the volume of oak and ash permitted for logging by these documents should determine how much of these species will be exported from Russia. We do not want to see authorization for X cubic meters of logs be "recycled" and used again. This is often a challenge for buyers who believe they are receiving genuine documentation—because in fact, the document was genuine for the first use, just not repeated uses.
Therefore, in addition to buyers carefully scrutinizing the documentation offered to them, WWF believes it is crucial for the Environmental Monitoring Agency to develop a regularly updated database of the documents presented to the Environmental Monitoring Agency to procure a CITES export permit, and to keep track of the volume exported under each document (keeping in mind that after processing the exported volume will only be a part of the larger, roundwood volume authorized for logging in the documents). This will allow Russian officials to ensure that the same documents are not used multiple times to launder illegally harvested wood.
If such steps are taken, CITES listing could play an important role in excluding illegal Mongolian oak and Manchurian ash timber from the market, and shifting competitive advantage to those companies that operate on a legal basis.
Any other “best practice” recommendations?
Know your source. It is essential that companies know the country of origin of their wood products, as often Mongolian oak and Manchurian ash from Russia can be incorrectly labeled as originating from forests in China or other countries. WWF also recommends that companies source wood products certified by the Forest Stewardship Council, which has developed detailed standards for legality as well as social and environmental considerations for responsible forestry.
Thank you, Linda, and thanks to all of the good work you and others at the WWF and GFTN groups do to support legal and responsible trade. Next week, we’ll look a bit more at this new CITES listing.
Tuesday, June 10, 2014
Alphabet Soup Series, Part 13 of Many: CITES
CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is an international treaty governing trade in endangered or potentially endangered plants and animals. Roughly 5,000 species of animals and 29,000 species of plants are listed in one of three “Appendices.”
As buyers of wood products, the simple way to look at the Appendices is as three levels of risk and control, and to remember that CITES is country-specific.
As noted, CITES is a country-specific listing. So Quercus mongolica from Russia will be listed from the end of this month and have trade controls put into place, but Quercus mongolica from China will not be. Note that sometimes Customs will get confused by CITES listings—they will see the species on the list, but not note the country of origin. This has been a particular challenge for some species, like genuine mahogany, that grow in multiple countries. Always make sure you know the actual origin (required under Lacey, too, of course!) for your material.
- Appendix I, about 1,200 species, are species that are threatened with extinction and generally no trade at all is allowed.
- Appendix II covers about endangered 21,000 species or species that are either similar to or potential substitutes for others on the listing. Trade is controlled with documentation checks and special licensing requirements.
- Appendix III includes about 170 species which have been listed by the country of origin to help control their trade.
CITES can be a product-specific listing. A listing might cover logs, but not flooring.
Remember, too, that trade in CITES is under constant control. That means if you import a product under CITES control and then export it, you need documentation in both directions. The control of trade follows that material always; it’s not just related to the first trade. This is why CITES is always an issue for musicians—many guitars or other musical instruments have inlays or other material that are of wood now under CITES control. Musicians need to either have documentation showing the production was “pre CITES listing” or that the wood is properly controlled—and they have to carry that with them for every border crossing.
More information on CITES can be found here:
Stay tuned: In next week's post we'll find out more about Russian oak being listed on CITES at the end of this month.
Tuesday, May 27, 2014
It’s My Birthday
Normally I don’t worry about my birthday, at least I haven’t since maybe I was 12? I’ve got good friends who often surprise me with a cake or a pie, and sometimes I go out to eat, but most of the time, I don’t even think about it too much.
But this week I’m going to use it to reflect on the passing of time and how much things have changed ...
... nah, forget it. I’m taking the day off!
Wednesday, May 21, 2014
Typing EPA Commentary: Join Me!
Hi, All! I’m not going to have much of a blog today because I’m working on NWFA commentary on the new EPA regulations.
The key issue under discussion now is the requirement for third-party certification of downstream producers. Currently under CARB (and soon under the EPA), companies producing plywood and particleboard and MDF/HDF need to be independently certified that their production’s formaldehyde emissions remain under specified levels. At debate now is if engineered flooring will basically face a double certification burden—if companies producing engineered flooring will have to buy certified cores and then re-certify their own production.
One option being considered in response to that is setting a fixed emissions limit for all laminated products and then having companies self-certify that their product meets that level. They’ll have to take appropriate steps to ensure that’s true, and there will be penalties if they are found out of compliance.
A particular challenge is the issue of how to handle three-layer production. CARB originally excluded lumber core from the covered construction categories. The EPA has stated that they feel they are mandated by how Congress wrote the legislation to include lumber core. (Because the EPA is adding it, CARB is considering following suit.) If so, depending on how the final regulations come down, engineered flooring manufacturers using plywood or HDF will have to buy certified cores and will self-certify that their final product meets a specified emissions level. However, those producing any type of layered lumber core product will have to go through the costly certification process directly. There doesn’t seem to be much of a way around this, although it makes no logical sense in the real world. (It came from Congress—should I really be expecting logic?)
This means a whole new group of companies that have never gone through CARB will be expected to suddenly figure out the certification system—build testing chambers, write manuals, etc. I hope we’re given enough time.
There are plenty of other issues to comment on—ensuring confidentiality, protecting the small manufacturers, determining exactly what testing protocols are used and then there is plenty to cover on the label question!—but for the wood flooring industry, this lumber core twist is a big challenge, and I’m not sure how it’s going to get resolved.
I would encourage everyone to go and post a short statement along the lines of:
I would like to encourage the EPA to:
Comment now, please—they need to hear from you! Feel free to cut and paste!
- Exclude laminators and fabricators from the TPC certification system.
- To develop a de minimis level that would reduce the regulatory burden on small businesses producing custom flooring.
- Continue the exclusion of lumber core engineered flooring from the TPC certification system by defining it as a finished laminated product rather than as hardwood plywood. If the product is included, ensure sufficient time for these newly included manufacturers to join the system.
- Have a simplified label to reduce market confusion and to reduce labeling burdens on retailers and distributors.
- Ensure long-term mutual recognition between CARB/EPA for accreditation, testing, and record keeping/reporting.
- Protect confidential business information for all companies in the supply chain.
OK, while you do that, I’ll get back to typing…
Tuesday, May 13, 2014
What About Monnin Hardness?
Scott Leavengood of OSU is back with more on wood hardness! I’m just going to turn this post right over to him to address a question received a few months back on “Monnin hardness” testing. However, first I do want to say that it sounds like the wood flooring industry needs to look into creating a meaningful test (or tests) specific to our industry. And that test should also reflect the various forms our product takes—solid, engineered with various cores and face veneer thicknesses, and of course, the type of finish we might apply… anyone have any suggestions? Feel free to post ideas.
In the meantime, Scott, the floor (so to speak) is yours:
We received a great question from a reader about Monnin hardness. As the reader said, don’t the Brinell or Monnin hardness tests “…better replicate the abuse a floor takes from a high heel shoe?” Further, consumers want to know “…what damage is caused by constant pressure by the heel on the floor, not how much force is needed to cause a really bad dent.”
First, let’s talk about Monnin hardness. I must admit that I’d never heard of this test method. So I did a little research to learn more about it. Chapter 9 of the book In Situ Assessment of Structural Timber, describes several hardness tests, including the Monnin test. This test is similar to the other hardness tests except a larger ball (a cylinder, in fact) is used. You might recall the Brinnell and Janka tests involved embedding a ball of 10 to a little over 11 mm into wood. With Monnin hardness, the test involves embedding a 30-mm cylinder with a maximum load of 2 kN (about 450 lbs.) over a period of 5 seconds. The figure below (from that same chapter in In Situ Assessment of Structural Timber) shows the test apparatus.
Since it’s hard to measure the depth of the penetration (t), the width of the indentation (l) is measured instead and depth calculated from that. Monnin hardness is 1 over the depth of penetration.
And maybe you’re thinking now what I thought when I read about this test method—it sounds a bit challenging to accurately measure the width, too! That’s actually what the authors of the book chapter say: “Because it is not easy to measure accurately the width of the impression, the Monnin hardness is subject to greater experimental error than in the Janka test.” Looking back at part 4 of this series, you might recall that the same situation exists for the Brinell test—measuring hardness with the Brinell test requires measuring the depth of penetration. This is really tough to do accurately!
So there’s the bottom line, really. As the reader said, consumers want to know what damage is caused by constant pressure on a floor, such as by a heel vs. how much force is needed to cause the floor to dent (i.e., Janka hardness). And the Brinell and Monnin tests do seem to provide a better measure of hardness measured in terms of damage caused by constant pressure. So why is it then that most measures of hardness we see reported are from the Janka test vs. the other test methods? Well it seems the answer is due to two primary reasons:
In conclusion, we should mention that the test we now know as Janka has been modified from the original. Gabriel Janka’s test was originally developed as a modified Brinell hardness test; he expressed the results as the load divided by the projected area of contact. However the ASTM test has always reported the results as the load at a penetration of 0.222 inches (i.e., half the depth of the ball).
- Janka hardness involves less experimental error
- It’s an easier test to conduct.
Riggio, M., and M. Piazza. 2010. Chapter 9: Hardness Test. In: In Situ Assessment of Structural Timber. B. Kasal and T. Tanner (eds.).
Doyle, J. and J.C.F. Walker. 1985. Indentation Hardness of Wood. Wood and Fiber Science 17(3): 369-376.
Tuesday, May 06, 2014
Universities as a Business Resource, Part 2
We’re back with David Jones of Mississippi State University and Chris Knowles of Oregon State University, who are going to give us a bit more insight into the University Extension Program. (See last week's post from them here.)
Chris: As I mentioned, I work in wood products extension, part of the Forestry & Natural Resources group at OSU. There are about 25 of us who work in that group and we make up the largest group of forestry extension faculty in the country. The vast majority of our group focuses on forestry and forest management related topics.
There are four of us at the Oregon Wood Innovation Center who work with the wood products industry. We work with the forest products industry in a wide variety of ways, including providing continuing education (we offer a number of annual courses on topics ranging from sales to quality control to dry kiln operation), answering technical questions, conducting small-scale testing and research for companies, and assisting with development of new products.
I think the best way for you to understand how we work with companies is to provide some examples of projects we have completed in the past.
One of my favorite examples would be helping an Oregon company in their export program using some good solid wood science. In that specific case, the Oregon company was selling hemlock to a manufacturer in China. The Chinese customer was looking into switching to a supplier in Canada. The Chinese customer required some minimum strength properties for the wood, and the Canadian supplier claimed that hemlock from Western Canada met the minimum requirements but hemlock from Oregon did not. The company wanted to know if there was any previous research that would show if any strength differences exist between hemlock from Western Canada and hemlock from Oregon.
I dug into the literature on this topic and found a recent research project that happened to have been completed by one of my OSU colleagues that showed there was no difference in the strength properties between the two regions. The Oregon supplier provided their Chinese customer with the information and was able to continue doing business with this customer.
David: Like Chris, there are a group of forestry and natural resource Extension professionals in Mississippi. We cover everything from planting trees, the wildlife that occurs in the forest, to the products that are made from wood. Unlike Chris, I am the only Extension faculty member at the university that works with the forest products industry. This means I have to rely on other professors in the department that I work in. All faculty members at Mississippi State University are required to provide service: some do it through service to professional societies, others serve on committees, and in my department we as a group tend to provide service to industry.
An example of industry outreach I did recently was to a company that produces a type of furniture that is primarily used by funeral homes. They were having issues with wood drying, gluing, and damage during transportation. I visited the company several times and collected information about how they manufactured and shipped their materials. I was able to identify issues that they were having and the root causes of the problems. I then developed a training program for the company to educate the employees about wood, so that they could solve the problems they were having along with future issues they might encounter.
Above are just a couple of examples of how we have worked with companies in the past. There are countless other examples. So, if you have a question or a problem you need assistance with solving, we suggest you reach out to your local Extension agent and see if they can be of assistance. If you don’t know who your local Extension agent is, contact us and we can help you find them. Also, do check our websites, as we have a lot of information already posted and links to other resources.
Finally, while we’ll be happy to answer something simple on wood properties or drying techniques, we encourage you to be creative, too—we enjoy a challenge!
Tuesday, April 29, 2014
Universities as a Business Resource, Part 1
Today’s blog comes to us courtesy of David Jones of Mississippi State University and Chris Knowles of Oregon State University. Readers know that many (most?!) of my posts so far this year have been done with professors of wood science from several different universities. Now, I’ve been using universities as a resource for years—not just for blog posts—for everything from information on new technologies to marketing to testing services. And I thought it was time to really drive home what a terrific resource they can be for all of us. They have jointly penned a little essay on their work. Gentlemen, take it away:
As faculty members at Oregon State University and Mississippi State University, the question we hate being asked the most is, “What do you teach?” When we tell them that we don’t teach, they generally reply with a snicker and ask how they can get a gig like that. We then have to spend time explaining how it is that we can be faculty members and not teach—like we’re doing now…
Most people automatically assume that all faculty members at a university teach undergraduate students. While most university faculty members do, in fact, teach undergraduate students, not all do. This begs the question, if a faculty member does not teach, what do they do? Most universities have a three-part mission that includes:
Consequently, most faculty members teach, conduct research or do a combination of the two.
- Educating students
- Conducting research
- Service and outreach.
However, there is still one major responsibility that a small subset of faculty members have that we have yet to discuss: Extension. We both happen to be Extension faculty members. Extension faculty have the job of working with and educating audiences that are external to the university, including audiences such as farmers, foresters, community leaders, youth, business owners, and, in the case of our jobs, the forest products industry. That’s right, it is our responsibility to work with the forest products industry (primarily in the states of Mississippi and Oregon) and help connect them with the resources available to them through the University.
So what is Extension? The easiest way for us to explain Extension is to look at where Extension began—in agriculture. Up until very recently, the state of the art research in agriculture was conducted at universities. University researchers worked to solve problems faced by everyday farmers, including increasing efficiency, productivity and survival rates. These improvements in agriculture were useless unless the newly discovered information made it into the hands of the farmers who were actually growing our food. Seeing the need to communicate the results of university research to relevant audiences, Congress passed an act to create and fund the Cooperative Extension Service, more commonly referred to as Extension.
This act mandated a third mission for a small group of universities (known as Land Grant Universities) around the country: to “extend” the knowledge they generate to relevant audiences. This model still holds today, and it is likely that you have an Extension office in the county where you live. Today there are more than 100 Land Grant Universities around the country. You can find the Land Grant University closest to you here.
Extension started in agriculture, and to this day agriculture is the dominant focus. Other large-scale Extension programs that you may have heard of include 4-H and Family and Community Health. The Extension Service at Oregon State University has five primary areas of focus:
- Agriculture & Natural Resources
- Family & Community Health
- Forestry & Natural Resources
- Sea Grant.
I’m going to break here for length, but I’d encourage readers to visit both websites to see the impressive list of services these two universities can offer. For example, on the Oregon site, you can find a Shrink-Swell App to help industry professionals determine how much a piece of wood will expand or contract, depending on the air's temperature and moisture. Now that’s a handy tool! And did you know that MSU has a state-of-the-art mechanical testing laboratory or that they’ll help you with everything from monitoring your mill’s emissions to designing the perfect resin formulations?
Next week, Chris and David will give us some examples of specific business outreach they’ve done for the wood industry.
Tuesday, April 22, 2014
Getting Technical: Wood Hardness, Part 5: Resources
Scott Leavengood of Oregon State University was kind enough to pull together this list of resources for those of you interested in learning more about wood hardness.
ASTM Standard D143, 2009, "Standard Test Methods for Small Clear Specimens of Timber," ASTM International, West Conshohocken, PA, 2009, www.astm.org. 31 p.
ASTM Standard E10, 2012, "Standard Test Method for Brinell Hardness of Metallic Materials," ASTM International, West Conshohocken, PA, 2012, www.astm.org. 32 p.
ASTM Standard D7136, 2012. “Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer Matrix Composite to a Drop-Weight Impact Event,” ASTM International, West Conshohocken, PA, 2012, www.astm.org. 16 p.
Bektas, I., M.H. Alma, and N. As. 2001. Determination of the relationships between Brinell and Janka hardness of eastern beech (Fagus orientalis Lipsky). Forest Products Journal 51(11/12):84-88.
Forest Products Laboratory. 1999, “Wood Handbook—Wood as an Engineering Material,” Gen. Tech. Rep. FPL–GTR–113. Madison, WI: USDA, Forest Service, Forest Products Laboratory. 463 p.
Niemiec, S., G.R. Ahrens, S. Willits, and D.E. Hibbs. 1995. Hardwoods of the Pacific Northwest, Research Contribution 8. Forest Research Laboratory, Oregon State University.
And more casual but interesting stories and looks at Janka:
Article from Makezine.com: How Wood Hardness is Measured
Wednesday, April 16, 2014
Getting (Really!) Technical: Wood Hardness, Part 4: Janka vs. Brinell
We’re back with Scott Leavengood of OSU talking about wood hardness. Scott already gave us a detailed look at Janka. This time, we’re going to look at Brinell.
Scott, there is another way of testing hardness, right?
When wood scientists and wood science textbooks talk about wood hardness, it’s almost universally (from my experience anyway) a reference to Janka hardness. However, there’s another test known as the Brinell hardness test, named after Swedish engineer Johan August Brinell. The ASTM test for Brinell hardness is ASTM E10, but please note that this test is specifically for metallic objects – there is no ASTM standard for measuring the Brinell hardness of wood.
What’s the difference between the two?
As we discussed, the Janka test is where they take a steel ball and push it in one half the depth of the ball. They note the pressure it took to get to that depth. It’s basically a force rating. But with the Brinell, the force is a constant. The test involves pushing in a steel ball at a fixed pressure for a fixed period of time. A measurement is made of the diameter of the indentation which is then used to calculate a formal rating. It’s more of a measure of the “give” of the wood.
There is another variable—the type of ball used. Brinell is expressed as an “HBW” where the last letter indicates the type of ball used – ‘W’ for tungsten carbide, ‘S’ for hardened steel.
So the Brinell is a calculation? It’s not simple like Janka, an actual measured pressure number?
I once was told that every formula in an article cut the number of readers in half, so I hesitate to get more technical. In simple terms, Brinell hardness is calculated by dividing the test force by the surface area of the indentation. But if you want the actual math….
The test (to determine HBW 10/100--which means using a tungsten carbide ball of 10mm and a pressure of applied load of 100kg) is conducted as follows: The ball is brought into contact with the surface of the test specimen; the test machine head should move quickly enough such that the full load (100 kg) is reached within 1-8 seconds. This load is held for 10-15 seconds (possibly longer if the material “exhibits excessive plastic flow”) and released. The diameter (in two locations – one along the grain the other across the grain, 90° to the first measurement) of the indentation is then measured. The Brinell Hardness number is then calculated as:
Where: HBW = Brinell Hardness
F = nominal force (kgf)
D = diameter of the ball (mm)
d = diameter of the indentation (average of the 2 measurements in mm)
If that formula makes your head hurt, again it’s essentially the test force divided by the surface area of the indentation.
And what does that mean for wood?
As an example, if the average indentation diameter was measured as 5.6 mm, then HBW 10/100 would be 3.7, which is about the average for red oak.
You told me previously that the Janka for northern red oak is 1290 lbs. Is there any relationship?
Do you mean that if someone reported Brinell hardness for a species, could we convert it to Janka, or vice-versa?
Unfortunately, there is no such conversion factor, although some have tried to develop one. For example, Turkish researchers measured Janka hardness and Brinell hardness for eastern beech and then used linear regression to determine how closely they were related. The good news is they found that the values were related closely enough that “the Janka hardness of the wood specimens of eastern beech species could be converted into Brinell hardness and vice versa.”
And the bad news?
The bad news is the underlined part – a different formula must be determined for every species.
I guess the wood industry will stay with Janka for the moment, but it’s great to understand the difference. Thank you!
Tuesday, April 08, 2014
Getting Technical: Wood Hardness, Part 3: Comparing Species
Scott Leavengood of Oregon State University has more numbers for us this week on wood hardness. (Click here to see last week's post on the incredible variation in Janka hardness he found in just one board.)
Scott, you did some more testing for us?
Yes, we did some other species that we had around the office. For ponderosa pine, the average hardness on the tangential face was 490 lbs. and 504 lbs. for the radial face of the same piece (the published value is 460 lbs.). Red alder showed more of a difference—but again, in the opposite direction than I expected—the average hardness on the radial face was 563 lbs., and it was 828 lbs. on the tangential face (the published value is 590 lbs.).
The table below shows the other species and results. As you can see, for the species we tested, only ponderosa pine had an average anywhere close to published values. All the others were much harder than what is published.
So what’s going on here? Clearly the least we can say that wood is variable—highly variable! But do you have any explanations? Or advice on how to use this?
I can’t explain it all, unfortunately. On the black oak flooring, we saw a range in Janka hardness of nearly 1,000 lbs. in tests conducted about 2 inches apart on the same piece!
We do need to keep in mind that the published values for these species are for tests conducted on wood at 12% moisture content (we tested the samples at about 6% moisture content—and the strength properties increase as the moisture content decreases, i.e., wood is stronger when it’s drier). Further, the published values are for hundreds of test specimens. We only looked at 3-10 tests per sample here. It could well be if we tested a few hundred more boards, we’d come up with more similar values.
Wrapping things up here, what do these values really mean?
Again, they are a good measure of one critical property of flooring: resistance to indentation. But given the variability, how reliable are they? All wood is variable, so really the best we can do is specify an average, but maybe listing an average with a range and sample size wouldn’t hurt!
Is there some other property we could measure that would tell us something similar about resistance to denting in flooring?
The Janka and Brinell tests (I’ll look at Brinell later, OK?) both involve a relatively slow, steady pressure to examine resistance to indentation. However, many times we are also worried about dents that occur from dropped objects for example, that is, from an impact vs. slow steady pressure. Well, there are test methods for impact as well (such as ASTM D7136), and we do these sorts of tests on wood plastic composites and other materials at OWIC. However I’ve never heard of any such tests being applied to solid wood flooring. It certainly could be an interesting way to evaluate different materials as well as the effect of different types of finishes, for example a hard, brittle finish vs. a more pliable finish.
Can you do some more tests for us in another blog post? I’m curious about engineered wood flooring in particular.
My thanks to Scott (and Trina) for their help on this. Scott has promised to do more testing on floors, so we’ll return to this topic later this year.
Tuesday, April 01, 2014
Getting Technical: Wood Hardness, Part 2: Variations in Results
We’re back with Scott Leavengood of Oregon State University (OSU) talking about wood hardness.
Scott, last week you talked about how, scientifically, the Janka test is designed. Now, this week, tell me about how incredibly inconsistent the results can be!
Well, it certainly doesn’t take long for people that work with wood to realize the enormous variability in this wonderful, renewable raw material. Part of that has already been addressed with regards to grain orientation; as discussed earlier, the ASTM Janka hardness test specifies measuring hardness on the radial surface, tangential surface, and end grain. It’s logical that there’s variability between species, of course—oak is much harder than basswood. But there’s also variability within species, and even within an individual board.
So we can assume that hardness varies with grain orientation. But by how much does it vary?
Janka hardness is one of the properties we measure often at the Oregon Wood Innovation Center (OWIC). So we decided to do a little test: We measured Janka hardness on several pieces of wood we had lying around, including a piece of California black oak (which is in the red oak species group).
The published Janka hardness value for this species is 1,100 lbs., which is not quite as hard as the generally accepted level of 1,290 lbs. for northern red oak. We tested this small piece of quartersawn flooring in five places, including a couple of times on or near a knot and got an average hardness of 3,066 lbs.—nearly three times the published value! But again, we tested right on or very near a knot in a couple places. But even without those knotty values, the average hardness is 2,521 lbs., which is well over twice the published value—and the range was from 1,810 lbs. to 2,948 lbs., again, not including the two tests directly on a knot:
Normally we expect higher values on a radial face (quartersawn) than on a tangential face (flatsawn). However, our tests on other pieces didn’t show that to be the case. In fact, there was either no substantial difference, or the results went the other way.
Fascinating. Love that oak picture—such amazing variation. Any idea why is there such a difference in hardness even on the same piece for measurements taken just a few inches apart?
It wasn’t at all obvious looking at the samples, so we decided to look under the microscope. And right off the bat, I’d like to thank Trina Evensen, one of my Renewable Materials students, for doing all the hardness testing and microscope work.
Trina cut through the indented portions of the California black oak flooring to have a closer look. These are both from the same piece of flooring and, again, about 2 inches apart. Can you see a difference? On the lower piece that rated at 1810 lbs., the wood cells fractured, so the failure was relatively abrupt:
The dots you see inside the circled area are the large earlywood pores (end grain). Compare that to the sample on the top, and you can’t see any fractured cells or end grain. These cells simply compressed and deformed throughout the duration of the test, so the hardness value was quite high.
This is the first time I’ve looked at a hardness test this way, but it does seem to agree with what I’ve seen many times—when the test values are low, you typically see fractures within the indentations; and when they are high, the indentations are often very smooth—almost like you’d see on metal or plastic.
Fascinating, Scott, thank you! Can we do more?
Absolutely! I’ll pull together a few more numbers for you and then you can also send me some samples and I’ll get you more tests later this year.
Sounds like a plan, thank you!
Tuesday, March 25, 2014
Getting Technical: The Scoop on Wood Hardness, Part 1: What is Janka?
Continuing our series, “Getting Technical,” this week, I’m going back to Oregon State University’s Wood Innovation Center to talk to Scott Leavengood, about wood hardness. Scott has agreed to offer up a multi-part miniseries on wood hardness. This week we’re going to start by discussing Janka generally and then we’re going to go in depth, really “hit the point” into the wood. (That word play that makes more sense when you consider what the Janka test really is…)
The tip of a Janka test ball.
When it comes to flooring, there’s one physical characteristic that seems to be the first question many people ask: What’s the hardness? Most folks seem to feel that’s going to indicate the performance of the product. Certainly, most of us understand that the quality of manufacturing, particularly the quality and type of finish, will be more important in the long term than the wood itself, but we still need to understand hardness basics. So how is it measured? And how reliable and valid are the test results? Scott and I take a shot at addressing those questions in this and subsequent posts. And to the readers, please know while we may get a bit technical at times, you’re going to want to pay attention to this series—I think some of the test results that Scott and his team did specifically for this series will really interest you!
Scott, thanks for doing this. So let’s start by just looking at “Janka.” Can you give me something of the history of the test? For example, what does the name mean? And how is it pronounced properly? Hard J or soft? “jan-ka or” “yank-a?”
Well, everybody I know calls it the Janka test with a hard J, however, given that it's named for an Austrian, I wonder if the Y isn't more accurate. Maybe it's like “rodeo”— ask a Texan how to pronounce it, then ask a native Spanish speaker... And according to everyone’s very fast reference source, it’s related to the name “John,” which would imply the softer version, as well.
The Austrian in question is Gabriel Janka, who worked for the Forest Products Lab of the U.S. Department of Agriculture (USDA). He was asked to scientifically measure the hardness for U.S. hardwoods. He developed this test that we use to this day (since formalized by the American Society for Testing and Materials (ASTM)).
OK, so how are we going to test for this?
In many tests of material properties, we measure one property to serve as an indicator of some other property of interest. For example, veneer mills often measure how long it takes for a sound wave to travel from end-to-end on a sheet of veneer; in simple terms, the faster the travel time, the higher the density of the wood and therefore, in general, the greater the strength. This technique is used to grade veneer for engineered wood products, like the flanges on wood I-beams used for floor joists.
Hardness, however, is one of those properties where we essentially directly measure the property of interest. With a wood floor, one critical performance criteria is the likelihood of the wood denting due to pressure from a stiletto heel, the tip of a small chair leg, a rock stuck in the sole of a shoe, etc. And so the standard test methods essentially replicate that process by embedding a metal ball into the wood and then reporting the force required.
So I can take any ball bearing and try to push it into wood?
As with every good scientific test, you want to follow an established standard so that your test results can be duplicated by others. We use the ASTM’s standard D143 for measuring the mechanical and physical properties of small clear specimens of wood.
The standard specifies using “clear specimens” to avoid the variability that can occur due to features such as knots, pitch streaks/pockets, decay, etc. While we rarely use “small clear specimens” in practice, we have greater assurance that we can compare species since the published test values were from tests conducted on clear materials. That is, it would make little sense to compare the hardness of red oak measured on a knot vs. the hardness of hard maple measured on clear wood.
So what are the specifications for a Janka test?
ASTM D143 measures hardness by measuring the weight force required to embed a 0.444 inch diameter ball to half its diameter into a test specimen. (See the image at the top of the blog? Note, the collar ensures the technician is able to stop the test when the ball is embedded to half its depth.) Of course we want to be more specific: The test standard further states that the load shall be applied continuously at a rate of ¼ inch per minute; test specimens should be 2” thick x 2” wide x 6” long and the test is to be conducted twice on a radial surface, twice on a tangential surface, and once on each end; the reported value is then the average of the six values (four on surface/edge grain plus two on end grain).
Got it. What kind of results might we get?
The USDA Wood Handbook: Wood as an Engineering Material lists the side hardness (average of radial and tangential—but not end grain) values for dozens of wood species. For example, at 12% moisture content, the hardness for northern red oak is 1290 lbs., for sugar maple it’s 1450 lbs., and for basswood it’s 410 lbs.—so now you can stop wondering why we don’t see more basswood floors!
Do a Google search on “Janka floor rating” and you’ll see hundreds of colorful charts comparing species. Remember though, these are averages only and that many other factors are going to go into the final flooring performance.
Thanks, Scott. Next week, let’s look at some actual tests.
Wednesday, March 19, 2014
Getting Technical: Wood Identification, Part 3: Tropicals
In our final post on wood identification with David Jones of Mississippi State University, we’re looking at tropical hardwoods. (Here are the links for Part 1 and Part 2 of our species ID discussions.)
David, again, thank you so much for doing this. To wrap up this basic review of wood identification through cell structure, tell us about tropical hardwoods.
Tropical hardwoods have their own unique challenges when trying to identify them using standard methods. The first challenge is that there are several species groups that utilize a common name that bears no relationship to the actual species of trees that they come from.
They are simply grouped together based on gross anatomical similarities, usually color, and because it makes some type of marketing sense. The best example of this is mahogany. True mahogany is part of Swietenia genus, but most of the legally traded mahogany is from species that are not considered true mahogany from a botanical standpoint. There are approximately 15 species that are traded now that are called mahogany. Most familiar would be the “African mahogany” grouping, which are various species in the Khaya genus, the use of “Philippine mahogany” to describe the Shorea genus (which is known most frequently as meranti in other countries) and, of course, the flooring industry identifies Myroxylon balsamum as santos mahogany.
Of course, this can happen in some temperate species, too, for example, the group of poplar, which can contain yellow-poplar or tulip-poplar (Liriodendron tulipifera), eastern cottonwood (Populus deltoides) and white poplar (Populus alba), of which the latter two are the only ones that are in the actual poplar genus. But it’s easier to identify temperate hardwoods than tropical.
Why is it difficult to identify tropical species?
Tropical hardwoods often do not have the growth patterns as temperate trees. Because tropical trees have the ability to grow continuously throughout the year, growth ring boundaries are not present. Because we often rely on seasonal changes from earlywood to latewood or marginal parenchyma at the end of the growing season to help with identification, tropical hardwoods can be difficult to deal with.
Further, tropical hardwoods can vary in color, hardness and strength based on where they were grown, what the growing conditions were, and how they were handled after they were cut and turned into products. The sapwood of purpleheart (Peltogyne) is actually white before the heartwood is formed, and the heartwood is purple but oxidizes to brown after being exposed to air for an extended time. Greenheart can vary from brown to green. In both cases using color as an indicator is not recommended.
Isn't that true for temperate hardwoods and softwoods, too? Is there a greater difference between, say, ipé in Brazil and Paraguay or northern/southern red oak?
It is certainly true that the color of our temperate hardwoods can vary. Red oak is a good example of that—it can be a pinkish red or it can be completely white. However, I believe that the variation in color of tropical woods is much greater than that, often to the point that without looking more closely, you would think because of the color difference that the wood could not possibly be the same species.
Any other issues?
Finally, because tropical woods can also have silica deposits and gums in the pores, the hardness of two identical pieces of wood may be different. This difference is more often detected in the machining process rather than when a processed sample is being identified.
The bottom line is that, like many domestic woods, some identification can be done on gross anatomical features, but the majority of tropical woods need to be identified utilizing a microscope to look at the ultrastructure of the wood, and, even then, many of the species can only be identified down to genus or species group.
How then do you really know what the tree is—is it through leaves and bark and something else if you can't tell from a wood sample?
The only true way to know what species a wood/tree is is to examine the leaves, bark, and ultimately the flowers. Many of the different species are separated out on the characteristics of the reproductive parts of the tree. That's why telling the difference between red oak lumber that comes from different species of red oak is impossible to do without seeing the bark, leaves, buds, or flowers. Just looking at it through a microscope might tell us that it is red oak, not white, but I usually won’t know which red oak it is without seeing the tree itself. The challenges are magnified with many of the species in the tropical regions of the world.
So what does that mean for identification for legality purposes? Does that mean it's not always possible to know if the ipé is from Brazil or Paraguay? And would a DNA study possibly answer that?
With very rare exceptions, it is impossible to specify the location from which a sample of wood has come from using tools of wood identification. This is one reason why the potential of DNA testing is so important, although it hasn't met the expectations that we had, at least not yet. And DNA, of course, tells us more where the wood was from, rather than answering that basic question of what the wood is.
Thank you, David.
Tuesday, March 11, 2014
Getting Technical: Wood Identification, Part 2: The Cells Themselves
We’re back with David Jones of Mississippi State University for more on wood identification (for Part 1, click here). He’s going to take us through the identification process for hardwoods.
David, where do we start?
You should prepare the surface of a wood sample before you examine its cells. Preparing the cross-sectional surface of a piece of wood properly can be frustrating and time consuming, but it is worthwhile. Make a thin, clean cut across the wood’s surface with a sharp knife or razor blade. Make the thinnest slice possible to reduce tearing of the wood.
After removing the slice, use a hand lens or magnifying glass to look at the surface. Identifying wood is often a process of elimination. Look for different cell types and write down what you observe. Your notes will help you remember what you have seen and help you identify the wood.
Are there a lot of different cell types to learn? And are they easy to tell apart?
There are four major cell types, fiber tracheids, vessels or pores, longitudinal parenchyma, and ray parenchyma. All of the cell types are easily identified, so there is no confusion about what they are, and each one serves a unique function in the tree.
Are cells the only thing to look at?
No, that’s just the start. After you determine a piece of wood is a hardwood, you should examine the pores in greater detail. Remember that hardwoods contain vessel elements, or pores, that softwoods do not have. You will want to examine the size, distribution, and changes in number of pores to identify the type of hardwood.
Hardwoods can be classified into three groups based on the pores:
• Ring-porous hardwoods, oaks and elms, have pores that transition from small to large abruptly from the earlywood to the latewood. The largest of the pores are clearly visible to the naked eye:
• Semi-ring porous hardwoods such as walnut, pecan, and hickory have pores that gradually change from small to large in a growth ring:
• Diffuse-porous hardwoods yellow poplar, gum, and maple have pores that are the same size throughout the growth ring:
Pores are also distributed in other ways in wood. They can be arranged as follows:
A. Solitary pores: Individual pores evenly spaced.
B. Pore chains: Multiple pores chained together.
C. Nested pores: Clusters of pores connected together.
D. Multiple pore: Two or more pores clustered together.
E. Wavy bands: Bands of pores with a wavy appearance.
There is actually a lot of difference in these woods. The pictures really help, thank you. So we have cells and pores, and…?
And we have wood rays which look like small stripes that go from one edge of a piece of wood to the other edge on the cross-sectional face. Wood rays transport food and water horizontally in the tree.
The rays in most species are unique and allow for easy identification. Oaks, for example, have very large rays that are visible to the naked eye. Sycamores can also be easily identified by the number of rays.
That’s what makes “rift and quartered” flooring and other and other “figured” wood so distinctive, right?
Exactly. When you saw the lumber, you slice open these rays, making the surface patterns. But beyond the aesthetics, examining the tangential and radial surfaces of wood for the characteristics of rays can help you identify wood species. Rays vary both in height and width, so examining both surfaces is key. Looking at the tangential surface will allow you to look at ray height. Some rays are several inches tall, while others are difficult to see at all.
The rays in oak can be over an inch high (white oak) or less than an inch (red oak). Examining on the radial surface will allow us to see what is called the ray fleck, of the wood. The fleck is where rays have been cut longitudinally and give, in the case of oaks or cherry a “tiger stripe” effect.
If rays are present in every hardwood, why don’t we see significant figure in most species?
Because many of the rays are only one cell wide, we call these unisariate rays. They can be so narrow in fact that without the aid of a microscope they can’t be seen.
And why do rays seem to shine?
The angles of the cell walls and the parenchyma cells around them tend to make them catch light in a desirable way. Many of the woods we utilize are simply used because of the way light seems to dance back from their surfaces.
That helps so much! So next week tropical hardwoods?
I can do that.
Tuesday, March 04, 2014
Getting Technical: Wood Identification, Part 1: Getting Started
This year, I think we need to explore more the science of wood. I’m going to be continuing the series “Getting Technical” that started with Chris Knowles of Oregon State University (OSU) discussing stable isotopes and DNA. This week I’m turning to David Jones of Mississippi State University for more on wood identification. He’s moving us from DNA in cells to the actual cell structure.
David, talk to me about cells!
Like a tree’s leaves, its cells and cell types are distinctive. Different cell types make it possible to identify wood long after all of the leaves and bark have been removed. The size, type, shape, and distribution of these cells allow the trees to transport water and nutrients to the crown and then food back to the cambium and roots, from the leaves.
Wood (also known as xylem) serves two functions in a standing tree. One function is to keep the tree standing tall and to withstand wind. The second function is to move water and nutrients from the soil to the leaves of the tree. After a tree has been harvested, water will continue to move in and out of the wood freely.
There are several wood types within a tree. They are named based on when the wood was formed or where the wood is within the tree. Heartwood is the center of older trees and is often darker because of the chemicals deposited there as the tree ages. Sapwood is the younger wood in a tree and is active in transporting water and nutrients. It generally has a lighter color and is closer to the bark.
Each year trees add one growth ring. In some species, the ring can be further separated into earlywood (wood formed in the Spring) and latewood (wood formed during the summer).
What about the differences between hardwood and softwood?
That’s right--trees are generally classified into two different types: hardwoods and softwoods. This classification has nothing to do with the wood itself, but with the type of leaves and flowers the tree has. However, we will also note significant differences in their cell structures as well.
About 90 to 95 percent of softwood cells are called longitudinal tracheids. They transport water. Because there are so few other cell types in softwoods, it can be difficult to distinguish between types of softwoods.
The structure of hardwoods is much more complex. There is also a lot of variation from one species of tree to another in hardwoods. Hardwoods contain vessel elements, or pores, that softwoods do not have. Pores vary greatly; they can be very small, very large, present in great numbers, or almost completely absent. If pores are present, the wood is a hardwood. If no pores are present, it is likely a softwood. Tropical hardwoods have their own distinctive look, so I’ll cover them separately.
Got it. So how do we use this to identify wood species?
There are three surfaces, or planes, that we look at to identify wood. These surfaces allow us to see different cells and structures in the wood.
When a tree is cut down, the flat surface of the stump is the cross-sectional surface. The cross-sectional surface shows most of the cell types needed to identify wood. The tangential surface is the next most important surface, followed by the radial surface.
That’s a great start. Next week, can you walk me through the identification process?
Absolutely. We’ll prep some samples for you to study!