American hardwood lumber grading Q&A series: article no. 2

June 2007
by Bob Sabistina, Grading consultant to the American Hardwood Export Council

This month's article will continue to answer questions I have received from buyers throughout the world. If you have a question regarding the rules for grading American hardwood lumber or if there is any other topic you would like to see in future articles pertaining to hardwoods from the USA, please contact me at: bshardwoods1@yahoo.com.

What are the grading rules for American black cherry?

The National Hardwood Lumber Association (NHLA) grading rules for American black cherry fall into the category of Standard Inspection. When NHLA Standard Inspection is referred to, the hardwood species is graded in accordance to the Standard Grades of the NHLA. (See AHEC's The Illustrated Guide to American Hardwood Lumber Grades for an explanation of the NHLA Standard Grades.) Important to note for cherry are several characteristics that are inherent to the species and are not considered defects. Notably, gum streaks and spots are admitted without limit and small 1/8 inch (3.18mm) pin knots are admitted in the clear-cuttings as well. Sapwood is not considered a defect according to the Standard Grades. A buyer and his supplier can add their own restrictions as to the amount of sapwood allowed in cherry, but this is an exception to the Standard Grades and must be spelled out in the contract for the shipment.

In your last article, you talked about an 80/20 mix for the FAS/ FAS1FACE grades. Is there a rule for what percentage must be included in a shipment?

No, there is not a rule dictating what percentage of a shipment of uppers needs to be FAS versus the grades of Selects or FAS1Face. I wrote on page 4 of The Illustrated Guide to American Hardwood Lumber Grades that “often export shipments are assembled with an 80-20 mix”, which has led to some confusion for the overseas buyer. What is most important can be found further on in the paragraph which reads; “These percentages are strictly left to individual buyer and seller agreement.” Just like the buyer and seller agreeing to a sapwood limit in cherry, these percentages are NOT dictated by the NHLA rules. They simply give scope for flexibility within the rules and allow for a degree of competition from one supplier to the next.

I placed an order with a new supplier for FAS white ash and received a large percentage of the shipment that was brown. The supplier is telling me that this is on grade and that if I wanted white (i.e. all sapwood) boards, I should have specified this in the contract. What can I do about this?

Unfortunately for you, your supplier is correct. White ash is a species of hardwood, where the heartwood (i.e. the centre of the log) is brown.  The NHLA grading rules for ash all come under Standard Inspection. So, if you wanted to receive “white or sapwood” boards, it should have been written in to the contract as an exception to the Standard Grades. For future shipments you should apply the sapwood requirements for hard maple that I discussed in last months issue to ash and receive the white wood you are looking for.

I read in AHEC's The Illustrated Guide to American Hardwood Lumber Grades that, to qualify for FAS, a board must be at least 6 inches (15.24cm) wide. However, I always receive boards that are less than this. Is AHEC's guide different to the NHLA rules or am I missing something?

AHEC's publication is the NHLA rules in a condensed version. What the chart on the back page is referring to is the Green Standard grades; i.e. measurement before kiln-drying. When hardwoods are kiln-dried, it is acceptable for all the boards in a shipment to be ¼ inch (6.35mm) narrower (i.e. 5¾ inches) and for a small percentage to be up to ½ inch  (12.7mm) narrower (i.e. 5½ inches). This does not change the percentage of clear cuttings required to make the grade; it simply recognizes that green lumber will shrink in the kiln-drying process.

Can you please remind me how each board is measured?

Each piece of lumber is measured for its width and length in determining the grade. The width is measured in inches. The length is measured in feet. (For conversions, please refer to The Illustrated Guide to American Hardwood Lumber Grades). When recording a board for sale, the widths are rounded to the nearest whole inch, thus 5¼ inches is tallied as 5 inches and 5¾ inches is tallied as 6 inches. If the board falls exactly on the half inch, the rule is to alternate fairly between rounding up and rounding down. Lengths are always rounded down to the whole foot. Therefore, a 10 foot 4 inch board is tallied as a 10 foot board and a 10 foot 10 inch board is also tallied as a 10 foot board. In other words, a board is not 11 feet long until it is 11 feet long!

We occasionally receive American tulipwood with large areas of purple-coloured wood. I must admit that I, personally, like it, but it drives our finishers mad. What is this and can I order tulipwood without it?

The purple colour you are referring to is a natural mineral inherent in tulipwood. In the upper grades, it is limited to twice the length in inches by full width of the board. For example, an FAS board 6 inches wide and 8 feet long would be allowed to have a combined total of 16 inches by full width of the board and still be considered for the FAS grade. This purple colour is not limited in the Common grades. Having reviewed the rules, I would suggest that you ask your supplier to leave these boards out of your shipments if you are buying uppers and limit them to outside the clear-cutting areas on the No. 1 Common grade. Typically, this purple coloured mineral is isolated and it should not be too much of a problem for your supplier to mark it as a lower grade. And I agree with you, I like the purple colour too!

Why are species such as cottonwood, tulipwood and basswood considered hardwoods when, on the contrary, they are relatively soft? Isn't this somehow deceptive?

The terms hardwood and softwood were never meant to be used to describe the 'hardness' of a particular wood species. They are strictly used to classify whether the tree is a deciduous, broadleaf tree (hardwoods) or a coniferous tree with needle-like leaves (softwoods). I always use this analogy about wood usage in the United States, where timber-frame construction is the norm; we build the house out of softwoods (joists and framing) and we furnish the house with hardwoods (flooring and cabinetry).
I encourage you to e-mail me any questions or other related hardwood topics you would like to see in upcoming issues.

American Hardwood Export Council
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 it efforts on providing architects, specifiers, designers and end-users with technical information on the range of species, products and sources of supply.

AHEC produces a full range of technical publications which are available free of charge by visiting www.ahec-europe.org, www.ahec-india.org, www.ahec-middleeast.org, www.sustainablehardwoods.info & www.americanredoak.info or by faxing (44) 20 7626 4222.
For more press information, please contact: Lucy Peacock/Melissa Green
American Hardwood Export Council, lucy.peacock@ahec.co.uk/melissa.green@ahec.co.uk.