Douglas Fir lumber products are identified by region. Products from trees growing west of the Cascade Crest to the Pacific Ocean, the most abundant region for Douglas Fir, are simply identified as "DF" on the grade stamp. East of the Cascades, Western Larch grows intermixed with Douglas Fir. The two species are often kept separate in appearance grade products but are combined in Dimension products and marketed as "DF-L". Because Douglas Fir and Western Larch share nearly identical structural characteristics and physical working properties, the two species are interchangeable in Dimension products.  Douglas Fir grown in Canada is identified as Douglas Fir North or "D Fir (N)" as shown on the grade stamp "DFN"

Premium Quality Diistribution Ltd use's the following gradestamped National Grade Rule (NGR) Dimension lumber this is recognized by the Japanese Ministry of Land, Infrastructure and Transportation (formerly Ministry of Construction) for use in wood-frame construction.

As wood loses or gains moisture, it will shrink or swell until it reaches equilibrium with the constantly changing level of moisture in the air of its immediate environment. All lumber benefits from some degree of "seasoning," i.e. letting it adjust to the humidity conditions of its surrounding atmosphere before it is installed. Because of its cell structure, wood shrinks primarily in width and thickness and very little in length.

Douglas Fir is unique among all softwood species in that it is naturally dimensionally stable, having the ability to season well in position. Many builders prefer to cut, nail and fasten Douglas Fir in the "green" or unseasoned condition, allowing it to air dry during construction. As a result, coastal Douglas Fir structural lumber is often shipped unseasoned (indicated by S-GRN on the grade stamp). Framing lumber 2 inches and less (nominal size) in thickness can be shipped after seasoning to a moisture content of 19 percent or less, which is indicated by S-DRY, KD or KD-HT on the grade stamp. S-DRY can mean kiln dried or air seasoned, while KD and KD-HT specifically mean kiln dried. Regional market conditions and building trade preferences dictate local availability of dry or green products.

For millwork, remanufacturing applications or glued products, Douglas Fir is dried in temperature and humidity-controlled kilns or stacked and air dried until its moisture content (MC) reaches the desired level for an intended purpose.

The term "DRY" can be confusing in lumber terminology. In structural grades, "DRY" indicates a product was either kiln- or air-dried to a 19 percent or less moisture content level prior to surfacing. However, in appearance products (e.g. the FINISH and SELECT grades), "DRY" is defined in the Western Lumber Grading Rules as being a maximum of 15 percent MC and in these grades, 85 percent of the items will be shipped with a MC level of 12 percent or less.

Premium Quality's grade stamp assures conformance of the graded piece with its applicable and in accordance of the Western Lumber Grading Rules, and also to the West Coast Lumber Inspection Bureau's (WCLIB) West Coast Lumber Standard Grading Rules, the Pacific Lumber Inspection Bureau's Export R List Rules, the National Lumber Grading Authority's (NLGA) Standard Grading Rules for Canadian Lumber , the Redwood Inspection Service's (RIS) Standard Specifications for Grades of California Lumber and the Southern Pine Inspection Bureau's (SPIB) NGR and Scaffold Plank portion of the Standard Grading Rules for Southern Pine Lumber . These rules provide lumber users with a dependable measure for determining the quality and uniformity of lumber as well as its performance capabilities.  e-mail Premium Quality for more information sales@premiumquality.net