Tree-following: Basswood in South Dakota (barely)

From Trees as Good Citizens (Pack 1922).

"The man who loves trees should be able to identify them at a glance. ... he should make himself familiar with the trees most commonly found in his own section of the country and learn to know them by the names in everyday use." (Charles Lathrop Pack)

Like all tree-followers I love trees. And as Charles Pack advises, I'm on a quest to get to know trees of my "section of the country" (South Dakota). This month I made myself familiar with one common in the far eastern part of the state but otherwise absent—American Basswood, Tilia americana, also known as American Linden or Lime (but not a Citrus or even close). "Bass" probably refers to the tough fibrous inner bark or "bast", used to make ropes and mats.

Basswood in Newton Hills State Park, southeast South Dakota.

Basswood can sprout from stumps, and clustered trunks are common (Minnesota, Eli Sagor photo).

Basswood is a tree of the great Eastern Deciduous Forest ecosystem of midwestern and eastern North America. It reaches the western edge of its native range in southern Manitoba (or possibly Saskatchewan), the eastern Dakotas, and eastern Nebraska, Kansas, Oklahoma and Texas.

Dots mark states and provinces with Basswood, but not specific locations; FNA legacy map, labels added.

This map is common on the Web; arrows added where Basswood ranges farther than shown (Tree Library).

The map above is incomplete because it was made back when plant taxonomists recognized three species of Tilia in North America. But no longer. In his treatment of Tilia americana for the Flora of North America, John L. Strother explained why he recognized only one species and no varieties:

"I tried to see merit in taxonomies in which more than one Tilia species native to the flora area are recognized. In the end, my experiences with specimens and my attempts at using taxonomies that purport to delineate distinct species and/or infraspecific taxa of Tilia in the flora area led me to agree with [a long list of botanists] that taxonomic recognition of more than one native Tilia species in the flora area is not tenable." [This is followed by a thorough discussion of formerly-recognized taxa—read here.]

Strother's decision is fine with me. Being an identifier rather than a classifier, I tend to favor lumpers.

Basswood leaf, flowers, fruit (Pack 1922).

In the case of Basswood, Charles Pack's advice is easy to follow ... sometimes. Trees can be recognized "at a glance" when in flower or fruit. The small yellow flowers form distinctive drooping branched clusters attached by stalks to prominent leaflike bracts. This arrangement persists in fruit.

Distinctive inflorescences of Basswood, in bud; arrows mark where stalks emerge from leaflike bracts.

Basswood flowers are very fragrant and loved by bees (Tree Library).

Basswood fruits are hard round nuts (some sources say drupes, berries, or berry-like; Tree Library).

But without flowers or fruit, Basswood identification can be challenging. Consider the leaves. They are oval to almost round and fairly large (to 15 x 12 cm), with a heart-shaped asymmetric base and serrate margins.

Above and below: broadly ovate Basswood leaves—note asymmetric bases, serrate margins.

Unfortunately Basswood leaves are similar to those of Common or Western Hackberry (Celtis occidentalis), which also grows in hardwood forests in eastern South Dakota. In both species the base of the leaf blade can be asymmetric and margins are serrate. Supposedly Basswood leaves taper to a longer pointed tip (acuminate) while Hackberry leaves have short pointed tips (acute). But in the illustrations and photos I've seen the difference is subtle or maybe nonexistent. Leaf width and shape may be more reliable. Hackberry leaves usually are narrower than Basswood's.

Common Hackberry, Celtis occidentalis (Tree Library).

Bark on mature trees can be helpful. Basswood bark has narrow well-defined fissures, while Hackberry has bark with irregular thick corky ridges or protuberances.

Basswood bark (Tree Library).

Basswood trunks on either side of a corky-barked Hackberry, Newton Hills SP.

Basswood-canopy-gazing on a dreamy afternoon.

In reading about Basswood I couldn't resist a rabbit hole into the world of wood. There I learned that Basswood has extremely fine-grained wood (sometimes described as having no grain). Cells making up the vertical fibers of the tree are small, regular in size and densely packed, producing wood perfect for carving. "A sharp knife or gouge slides through it as if cutting butter" (source).

Basswood lobster under construction, by Dr.DeNo.

Another common use of Basswood is in solid-body electric guitars, for the same reasons. The fine grain and uniform density make machining and finishing easy (source).

Fender JV Modified '50s Stratocaster Electric Guitar, with Basswood body; available at Sweetwater.

Sources (in addition to links in post)

Johnson, WC, and Knight, DH. 2022. Ecology of Dakota Landscapes; past, present, and future. Yale University Press.

Nelson, G, et al. 2014. Trees of eastern North America. Princeton University Press.

Pack, CL. 1922. Trees as Good Citizens. Washington, D.C, American Tree Association. BHL. [This is a guide to planting shade trees.]

Charles Lathrop Pack, 3rd-generation timberman and one of the wealthiest men in the USA in his time, was passionate in his promotion of trees, including proper forestry and conservation. He wrote at least six books on the subject. Date of photo unknown, before 1918 (source).

This is my contribution to the monthly gathering of tree-followers, kindly hosted by The Squirrelbasket. Are you a tree lover? Consider joining us—more information here.