Yellow-poplar is probably the third most important hardwood in our Eastern forests, after maple and oak. Much of the yellow-poplar today is growing on excellent sites where the American chestnut used to grow in the late 19th century, before the chestnut blight wiped out these magnificent trees.
As a result, yellow-poplar is one of the largest trees in today’s Eastern forests, large in both diameter and height, often over 3 feet in diameter and 150 feet tall with over 100 feet of the stem without a branch. Yellow-poplar is a member of the magnolia family. In fact, from time to time, some lumber from cucumber tree or other magnolia is accidentally included with yellow-poplar lumber; such lumber is much whiter in color.
The volume of yellow-poplar in the forest continues to increase every year in spite of large harvests. In fact, yellow-poplar has been providing important forest products for the North American inhabitants for many centuries. For example, much of the early wooden tableware was made of y-p because of its smooth, even grain and freedom from odor and taste. Early European settlers used y-p for log cabins, although decay soon resulted in deterioration.
Many early barns were built with y-p siding when more decay resistant species were not available. In the early and mid 20th Century, virtually all glue-up furniture panels were made with y-p cores with fine veneer fronts and backs. Yellow-poplar has been used for every use from fine musical instruments to pallets and construction 2x4s, from veneer to particleboard and OSB, and everything in between. In addition to the valuable lumber, the bark, leaves, flowers, fruit and roots contain pharmaceuticals used in the mid 1800s in the U.S.
Yellow-poplar (Liriodendron tulipifera) is also called tulip poplar and tulip tree. Sometimes, it is called just poplar, which can lead to confusion with the true poplar species including aspen. However, y-p is not related to the aspen poplar or European poplars. Poplar is the state tree of Indiana, Kentucky and Tennessee.
Processing suggestions and characteristics:
Density. Yellow-poplar averages about 26 pounds per cubic foot at 7 percent MC. This is roughly 80 percent of the weight of soft maple. A planed, dried piece of lumber will weigh about 1-1/2 pounds.
Drying. Yellow-poplar is perhaps the easiest drying species native to North America. Some blue stain can develop if drying is not aggressive enough or if logs or green lumber was stored rather than processed immediately.
Shrinkage in drying is 6 percent. Final moisture contents for y-p should be between 6.0 to 7.5 percent MC. Excessively dry wood will require increased glue spread to avoid a starved joint. MCs much over 8% MC will likely shrink as they dry in-use and may develop some warp or shrinkage defects.
Gluing and Machining. Yellow-poplar machines very well. Occasional growth stresses in the lumber can cause splits (sometimes called roller splits or planer splits) to develop when planing. Sharp tools will minimize any fuzzing. Yellow-poplar is very easy to glue. The softness means that the wood is quite forgiving, if gluing conditions are not quite perfect.
Stability. Yellow-poplar is subject to modest size changes when the MC changes–about 1 percent size change running across the grain parallel to the rings (tangentially) for each 3-1/2 percent MC change, and about 1 percent size change across the rings (radially) for each 6 percent MC change.
Strength. Yellow-poplar is medium-low in strength and stiffness. The bending strength (MOR) averages 10,100 psi. Hardness averages 540 pounds. Stiffness (MOE) averages 1.6 million psi. For comparison, soft maple values are 13,400 psi, 950 pounds and 1.6 million psi.
Color and Grain. The grain of yellow-poplar is fine and uniform in texture. The sapwood is fairly white with a hint of light tan color with an obvious light green hue. For "show wood" the sapwood is preferred. The heartwood tends to be greener in color. The annual rings make distinct patterns. Yellow-poplar has some dark colors in the older heartwood. Colors range from red to green to purple to very dark. In furniture and cabinets, this highly colored wood is usually avoided.