by Eric Meier

In the United States, the term “Poplar” almost always refers to a specific wood species: Liriodendron tulipifera. Other common names for this wood include Yellow Poplar, American Tulipwood, or Tulip Poplar. The only problem with referring to this species as “Poplar” is that it isn’t actually a type of poplar. That title properly belongs to a genus of trees appropriately named Populus. 

Types of Poplar

Liriodendron genus (not closely related to true poplars, it’s actually from the Magnoliaceae family, and is technically closer in relation to the various Magnolia species)

Yellow Poplar (Liriodendron tulipifera)Yellow Poplar (Liriodendron tulipifera)

Also referred to by the following names: Tulip Poplar, American Tulipwood, or simply “Poplar” (in North America).

Populus genus (this contains true poplars, as well as related trees such as cottonwood and aspen)

White Poplar (Populus alba)White Poplar (Populus alba)

Balsam Poplar (Populus balsamifera)Balsam Poplar (Populus balsamifera)

Eastern Cottonwood (Populus deltoides)Eastern Cottonwood (Populus deltoides)

Bigtooth Aspen (Populus grandidentata)Bigtooth Aspen (Populus grandidentata)

Black Poplar (Populus nigra)Black Poplar (Populus nigra)

European Aspen (Populus tremula)European Aspen (Populus tremula)

Quaking Aspen (Populus tremuloides)Quaking Aspen (Populus tremuloides)

Black Cottonwood (Populus trichocarpa)Black Cottonwood (Populus trichocarpa)

Characteristics of poplar wood

Regardless of the genus, all poplar woods (true or otherwise) have a few similarities.

  • They are all relatively lightweight and soft (as a matter of fact, Populus species rank among the very softest woods in the world).
  • They all have relatively small pores which finish to a smooth texture without the need for pore fillers. 
  • Most of these trees grow quite large and furnish wide, clear boards.
  • Anatomically, they are all diffuse (or semi-diffuse) porous hardwoods. 

Yellow Poplar vs Populus genus

Yellow Poplar (Liriodendron tulipifera) generally has a green/olive cast to certain portions of the wood. This can sometimes be enough of an indicator to separate it from other Populus species, but to ensure separation, a closer look at the endgrain is needed.

A helpful key in differentiating these two genera is in the rays. Yellow Poplar will have comparatively large rays that can even give the wood a modest amount of ray fleck on quartersawn surfaces. By contrast, Populus genus species will have very narrow rays that are invisible with the naked eye, and just barely visible at 10x magnification.

Yellow Poplar (endgrain 10x)

Upon closer inspection (10x) of the endgrain of Yellow Poplar (Liriodendron tulipifera), the rays are nearly the same width as the pores.

White Poplar (endgrain 10x)

The rays of White Poplar (Populus alba) are more subdued and aren’t quite as wide as the pores—as is typical in most Populus species.

Another characteristic of Yellow Poplar (Liriodendron tulipifera) is that the rays are noded. What this means is that whenever a ray crosses a growth ring line, it gets slightly wider and has a flared appearance. Populus genus woods will generally have rays of a uniform width throughout their entire length.

In this view of Yellow Poplar (Liriodendron tulipifera), the noded rays are subtly visible. (20×)

In this view of Yellow Poplar (Liriodendron tulipifera), the noded rays are subtly visible. (20×)

Populus species identification

For identification purposes, Populus species can be divided into two main groups: cottonwood (including poplars), and aspen. Species in the cottonwood group have a foul odor when wet, have slightly larger earlywood pores (edging toward semi-ring-porous), are coarser textured, have less natural luster, and are darker in color—never the stark white color found in some pieces of aspen. 

Cottonwood group (Populus genus)

Eastern Cottonwood (Populus deltoides)

Eastern Cottonwood (Populus deltoides)

Eastern Cottonwood (endgrain 10x)

Eastern Cottonwood (endgrain 10x)

Included species:

Characteristics:

  • Larger Earlywood pores
  • Heartwood grayish brown
  • Foul odor when green
  • Coarser texture (when compared to aspens)
  • Low natural luster

Lookalikes:

Willow (Salix spp.) Separation is tenuous, and is based on color. Willows tend to be more reddish brown, while Cottonwood Populus species tend to be more of a grayish brown.

Black Willow (Salix nigra)

Black Willow (Salix nigra)

Aspen group (Populus genus)

Quaking Aspen (Populus tremuloides)

Quaking Aspen (Populus tremuloides)

Quaking Aspen (endgrain 10x)

Quaking Aspen (endgrain 10x)

Included species:

Characteristics:

  • Smaller earlywood pores
  • Heartwood generally paler in color
  • Little noticeable scent, even when wet
  • Medium texture (when compared to cottonwoods)
  • Moderate natural luster

Lookalikes: 

Basswood (Tilia americana) The pale color and light weight closely matches aspen. However, as with distinguishing Yellow Poplar (Liriodendron tulipifera) from Populus species, the difference can be seen in the rays when looking closely at the endgrain. The rays of Basswood are much more pronounced than aspen, and are also noded at the growth ring boundaries.

Basswood (endgrain 10x)

Basswood (endgrain 10x)