07 June 2012
AHEC: American Hardwood Lumber Grading Q&A. by Bob Sabistina.
By Bob Sabistina, Grading consultant to the American Hardwood Export Council.
The Grading Rules for North American hardwood lumber were established over 100 years ago by the National Hardwood Lumber Association (NHLA), which is now headquartered in Memphis, Tennessee. I have been writing a series of articles, answering a variety of questions pertaining to the application of those grading rules. Questions in these articles have been generated from individuals in the hardwood trade all over the world. This month’s article covers questions I received recently at a woodworking trade show in Poland:
Question 1: We purchase American hardwoods in Poland from German distributors. Could you explain the difference between a gross tally and a net tally? There seems to be a big discrepancy among the distributors in the amounts being delivered and the prices being offered.
Answer 1: The board footage or volume in cubic metres of sawn hardwood will differ from the time the wood is fresh sawn to after it is kiln dried. This is because of the shrinkage that occurs when the water is removed from the lumber. To be consistent, no matter what the degree of dryness is, a net tally is the actual measurement of the wood after kiln drying. Gross (or green) tally refers to the measurement of the wood before drying and does not take into account the shrinkage which will occur in the drying process.
For example, 10 cubic metres sold on a gross tally will actually be about 7-10% less in volume than 10 cubic meters sold on a net tally. Typically the price is also indicative of this difference as well. When comparing prices from different suppliers you must keep this in mind. For a manufacturer to truly calculate yield and wastage and record throughput into and out of the manufacturing facility, a net tally going in will provide the most accurate data. Prices quoted on a net tally negate the need for any guesswork on the shrinkage factor that is being used in a gross tally.
The practice of adding footage as in a gross tally is not allowed by the NHLA rules. The gross tally is an industry practice and in no way condoned by the NHLA. My suggestion is to insist on a clear account on the bill of sale or the offer sheet on what tally is being offered and if it is a gross tally, how much shrinkage can be expected to bring the lumber to a true net measurement.
Question 2: Can you explain the difference between European poplar and American poplar?
Answer 2: The single most important difference is that “American poplar” or “American yellow poplar” is not a poplar (Populus) at all. In fact, it is Liriodendron tulipifera, a close relative of the magnolias. It grows abundantly in the eastern forests of the United States and was initially called poplar by the first European settlers coming to the New World several hundred years ago, on account of its height. When the American Hardwood Export Council began promoting American hardwoods worldwide in the late 1980s, the confusion over this valuable and versatile timber outside the USA became apparent. The decision was made to refer to it as American tulipwood, making reference to its botanical name and its tulip-shaped leaves. In America, however, it is still most often referred to as yellow poplar, or simply, poplar.
Today, American tulipwood is one of the most widely used temperate hardwoods in furniture and joinery worldwide. It machines very well, has excellent working properties, and will take a stain beautifully to imitate other more valuable woods like walnut and mahogany at a fraction of the cost. The trees grow straight and tall, allowing for the production of sawn boards in long lengths and wide widths. It dries exceptionally well and requires minimal kiln time, while maintaining good dimensional stability. It is also incredibly strong for its weight. Detailed structural data for tulipwood can be found on the AHEC website: www.americanhardwood.org or in the AHEC publication Structural Design in American Hardwoods.
The Populus species, which include European poplar, aspen, cottonwood and Pacific albus have lower strength values than tulipwood and are softer. In the main, these species have traditionally been used for the production of paper as core veneer stock for plywood and for industrial boxes and crates. In addition, aspen and cottonwood are regularly exported, particularly to Asia, where their uses include furniture components and moulding.
Question 3: Can you explain the normal procedure to follow when ordering hardwood lumber from America, and can I get mixed containers?
Answer 3: Typically, hardwood lumber from America is shipped kiln dried in 40 foot containers, which will hold anywhere between 26 and 36 cubic metres, depending on the species. There are no limitations as to what goes into a container, other than the overall weight of the wood. This means that you could request several species, grades, and thicknesses. Mixed containers are not a problem and initially a good way to learn about a supplier’s stock and more importantly, what will work best for your company. However, bear in mind that if you are ordering mixed items, you may only receive one or two packs per species or thickness so the spread of widths and lengths you receive may be limited compared to a full container of a single species and thickness.
A list of suppliers is available on AHEC’s website: http://www.americanhardwood.org/ahec-list-of-exporters/ - where you will find exporters listed by name, location and species produced. Alternatively, you can contact AHEC directly and send them an enquiry, which will be passed on to the exporters. Try to be specific about what you are looking for and provide details of species, thickness, grade and any other requirements you may be looking for, such as selected widths, lengths and colours etc. General enquiries for prices etc... are unlikely to solicit much of a response.
If you would like further information from me or if you simply want to ask a question, please contact me at firstname.lastname@example.org ."
More about AHEC
The American Hardwood Export Council (AHEC) is the leading international trade association for the US hardwood industry, representing the committed exporters among US hardwood companies and all the major US hardwood production trade associations. AHEC concentrates its efforts on providing architects, designers and end-users with technical information on the range of species, products and sources of supply.
For more information contact Mrs Belinda Cobden-Ramsay:
AHEC, American Hardwood Export Council
3, St. Micheal's Alleye
LONDON EC3V 9DS (England)
Tel. 0044 207 6264111
Fax: 0044 207 6264222