HardwoodSpecial lssue Yellow poplar: a marketable framing lumber

By Richard C. Allison Wood Products Specialist N. C. Agricultural Extension Service N. C. State University Raleigh, N.C.

OUR BUILDER customers are probably not familiar with yellow poplar framing lumber mainly because it has not been widely used for building construction in recent years.

Yellow poplar (Liriodendron tulipdera) lumber is also known as tulip poplar, poplar and whitewood in the trade. This lumber should not be confused with the Populus species (See page 36 in the July, 1984, issue of Building Products Digest).

Yellow poplar is a good building product. Wholesalers and retailers should be informed on its use as a framing lumber. The natural qualities of the wood plus demonstration studies and ready availability well qualify it for commercial use.

Yellow poplar has a smooth texture and a tight, straight grain with small to medium size knots. Poplar's appearance is white to light brown in color with some pieces having light to dark purplish and greenish streaks. This discoloration does not affect its strength.

A medium density hardwood, yel- low poplar weighs about 29 pounds per cubic foot. The strength and stiffness properties of yellow poplar framing lumber (the terms dimension, structural or construction lumber are used interchangeably in the trade) are similar to spruce-pine-fir dimension lumber. Yellow poplar's strength values rank it midway between the strongest woods (southern pine and Douglas fir) and structural lumber with less strength (hem-fir and aspen). It can be classified as a "middle-ofthe-road" construction lumber.

Story at a Glance

Tests verify yellow poplafs acceptance as framang lumber. .grade stamped material is building code approved nationally. .performance comparable to spruce-pine-lir. free literature, video tape available.

Yellow poplar framing lumber is manufactured under the National Grading Rules for dimension as most all dimension lumber is. This means standard softwood dimension lumber sizes and grades are used to manufacture and grade it. Poplar dimension is dried, finished, inspected and grade stamped like all dimension lumber being used today. This allows grade stamped poplar to be building code approved nationwide for building construction.

Several demonstration studies using yellow poplar framing lumber for building construction were made by wood products extension specialists at North Carolina State University. Over 5,000 board feet of No. 2 & Btr. graded lumber in 2x4 to 2xl0-inch widths were used for a demonstration house. The results showed the lumber has the strength and stiffness required for use as studs and floor joists.

It stayed straight after being installed even though the framing was left exposed for six weeks before