Grading guidance

Summary
• Gum streaks and spots are not classified as defects in American black cherry.
• The heartwood of white ash is brown.
• Board lengths are rounded down to the nearest foot.

Q: What are the grading rules for American black cherry?
A: The National Hardwood Lumber Association (NHLA) grading rules for American black cherry fall into the category of Standard Inspection. (See AHEC’s The Illustrated Guide to American Hardwood Lumber Grades for an explanation of the NHLA Standard Grades.) It’s important to note that cherry has several characteristics that are inherent to the species and are not considered defects. Notably, gum streaks and spots are admitted without limit, small 1/8in (3.18mm) pin knots are admitted in the clear-cuttings and sapwood is not considered a defect. 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.

Q: 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?
A: No, these percentages are strictly left to individual buyer and seller agreement. The NHLA rules simply give scope for flexibility and allow for a degree of competition from one supplier to the next.

Q: 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 (ie all sapwood) boards, I should have specified this in the contract.
A: Unfortunately for you, your supplier is correct. White ash is a species of hardwood where the heartwood 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.

Q: I read in AHEC’s The Illustrated Guide to American Hardwood Lumber Grades that, to qualify for FAS, a board must be at least 6in (15.24cm) wide. However, I always receive boards that are less than this.
A: 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 – ie measurement before kiln-drying. When hardwoods are kiln-dried, it is acceptable for all the boards in a shipment to be ¼in (6.35mm) narrower (ie 53/4in) and for a small percentage to be up to 1/2in (12.7mm) narrower (ie 51/2in). This does not change the percentage of clear cuttings required to make the grade; it simply recognises that green lumber will shrink in the kiln-drying process.

Q: Can you remind me how each board is measured?
A: Each piece of lumber is measured for its width (in inches) and length (in feet) in determining the grade. When recording a board for sale, the widths are rounded to the nearest whole inch, thus 51/4in is tallied as 5in and 53/4in is tallied as 6in. If the board falls exactly on the half inch, the rule is to alternate fairly between rounding up and down. Lengths are always rounded down to the whole foot so a 10ft 4in board is tallied as a 10ft board and a 10ft 10in board is also tallied as a 10ft board. In other words, a board is not 11ft long until it is 11ft long!

Q: We occasionally receive American tulipwood with large areas of purple-coloured wood. What is this and can I order tulipwood without it?
A: The purple colour 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 6in wide and 8ft long would be allowed to have a combined total of 16in by full width of the board and still be considered for the FAS grade. This purple colour is not limited in the Common grades. I suggest 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.

Q: Why are species such as cottonwood, tulipwood and basswood considered hardwoods when, on the contrary, they are relatively soft? Isn’t this somehow deceptive?
A: 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).

Bob Sabistina worked with the NHLA for over 22 years as a field inspector. AHEC offers NHLA grading for individual companies. If you have a question for upcoming articles, e-mail bshardwoods@yahoo.com