American basswood (Tilia americana): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Tilia americana L., basswood family (Silvics)
Other names	American linden, where it is planted as a shade tree in urban areas of the eastern states (Silvics)
Native status, USDA PLANTS	Native in the lower 48 states; Canada carries both the introduced and the native code
Size, Silvics	23 to 40 m (75 to 130 ft) tall and 91 to 122 cm (36 to 48 in) in diameter; under favorable conditions 43 m (140 ft) and 137 cm (54 in)
Longevity, Silvics	Estimates generally exceed 200 years
Green weight of the wood, NRS-38	41 lb per cubic foot, without bark

Native range and where it grows

The Silvics of North America handbook (Agriculture Handbook 654, 1990) says American basswood grows in a range that starts in southwestern New Brunswick and New England and runs west across Quebec and Ontario to the southeast corner of Manitoba. It reaches south over eastern North Dakota, South Dakota, Nebraska and Kansas into northeastern Oklahoma, then east to northern Arkansas, Tennessee and western North Carolina and northeast to New Jersey. It calls the tree the northernmost Tilia species, and says best growth is in the central part of the range on deep, moist soils.

The handbook says the species grows on soils from pH 4.5 to 7.5 but occurs more often in the less acidic to slightly basic part of that range, and describes it as a nitrogen-demanding species that grows poorly on sites short of nitrogen. It grows best on mesic sites but is also found on sand dunes near Lake Michigan and on dry rock ridges in Ontario and Quebec. Across much of its range it is restricted to moist sites on north- and east-facing slopes. It seldom forms pure stands. It is dominant in one forest cover type, Sugar Maple-Basswood, most common in central Minnesota and western Wisconsin, where sugar maple holds first place and basswood second.

Flowers and fruit

Silvics says fragrant, yellow-white flowers hang on loose clusters from long stalks attached to leafy bracts. Flowering is generally in June, from late May to early July depending on latitude, follows leaf-out and lasts about 2 weeks. A pollination study cited by the handbook identified 66 insect species from 29 families as pollinators, with bees and flies the most common by day and moths by night. The fruit is a nutlike drupe 5 to 10 mm (0.2 to 0.4 in) across, usually with one seed, ripening in September and October. The handbook says fruit is rarely carried more than one or two tree lengths from the parent, that animals probably increase seed dispersal significantly, that seed is slow to germinate because of an impermeable coat, and that in a northern Wisconsin stand only 2 percent of more than 7,400 identifiable seeds in the litter were sound. It lists seed-bearing ages of 15 to 100 years and calls basswood one of the most consistent fall-maturing seed producers in a 26-year Wisconsin study.

Sprouting, growth and roots

Silvics says basswood sprouts prolifically from the stump at ground level, and that almost all trees 10 cm (4 in) in diameter and smaller sprout, along with more than half of sawlog-size trees. This lets it keep its place in a stand beside the more shade-tolerant sugar maple. It classes basswood as tolerant of shade overall, and says it grows faster than most other northern hardwoods, often beating sugar maple and yellow birch in site index by 1.5 m (5 ft). Diameter growth in three unmanaged northeastern Wisconsin stands averaged 3 mm (0.11 in) a year. Seedlings first form a long taproot, which the handbook says gives way in saplings to a system of lateral roots.

Wood

The Wood Handbook (FPL-GTR-282, 2021) describes the heartwood as pale yellowish brown with occasional darker streaks and the sapwood as wide, creamy white or pale brown. The wood is soft and light, with fine, even texture, and the handbook says shrinkage in width and thickness is rated high but the wood seldom warps in use. Uses it names are boxes, wooden ware, apiary supplies, molding, venetian blinds, sashes and door frames, with some veneer, and it calls the wood a favorite of wood carvers. Silvics adds that the wood is valued for hand carving, and that the tree is well known as a honey-tree and its seeds and twigs are eaten by wildlife.

Wood Handbook figure	Green	At 12% moisture content
Specific gravity (Table 5-3b)	0.32	0.37
Modulus of rupture, lbf per square inch (Table 5-3b)	5,000	8,700
Side hardness, lbf (Table 5-3b)	250	410

The green weight is in the NRS-38 table, the same figure used in the log weight calculator.

Damaging agents the handbook names

Silvics says many insects attack basswood but few serious problems exist.

Borer. The linden borer. It digs long, winding tunnels, mostly low on the trunk, and the handbook says it may harm trees that are weak, very young or past their prime.
Defoliators. The linden looper, basswood leafminer, spring and fall cankerworms, whitemarked tussock moth, gypsy moth and forest tent caterpillar. The handbook calls basswood a highly preferred host for gypsy moth in New England and of intermediate susceptibility in southern Quebec. The spongy moth page sets out what the agencies record for that insect.
Leaf diseases. Anthracnose, black mold and a leaf spot, none of which the handbook says do serious damage.
Wood decay. The handbook says the wood decays easily once exposed, and that little defect is met in trees harvested before 120 years, with decay losses much more likely beyond that age. It names yellow-brown stringy rot as the most common stem defect in Ontario cull studies.
Animals. Mice and voles girdled trees in plantations on weedy old fields: in one southern Ontario plantation 44 percent of stems were completely girdled and 39 percent partly. Rabbits feed heavily on seedlings and small saplings.

The handbook adds that the thin bark is easily damaged by fire and that basswood is one of the hardwoods least susceptible to late spring frosts. For who takes reports of regulated pests, see reporting a pest in the United States, and pests and diseases by country sets out which ones agencies regulate.