Description

Tilia cordata is a deciduous tree growing 66–131 feet tall, with a diameter 1/3 to 1/2 the height, and a trunk up to 3 feet in diameter. The bark is smooth and grayish when young, firm with vertical ridges and horizontal fissures when older. The crown is rounded in a formal oval shape to pyramidal. Branching is upright and increases in density with age. The leaves are alternately arranged, rounded to triangular-ovate, 3–8 cm long and broad, mostly hairless except for small tufts of brown hair in the leaf vein axils—the leaves are distinctively heart-shaped. The buds are alternate, pointed egg shaped and have red scales. It has no terminal bud. The small yellow-green hermaphrodite flowers are produced in clusters of five to eleven in early summer with a leafy yellow-green subtending bract, have a rich, heavy scent; the trees are much visited by bees to the erect flowers which are held above the bract

The leaves are light to dark green with paler undersides. They have an ovate shape with a cordate base. The fall color is chartreuse. If the tree is under stress, the leaves are sometimes golden yellow. The flowers are fragrant and creamy yellow clusters that blossom in the summer. The fruit is a small hairy nutlet.

Habitat

The tree prefers full sun to partial shade, loamy, moist, and well-drained soils. It does not tolerate wet conditions, severe drought, pollution, or salt spray. It can be found in man-made or disturbed habitats, forest edges, and forests.

Tilia cordata is a drought-tolerant tree species. It is weakly, or not at all, affected by short periods of drought. A particular key strength of Tilia cordata is its tolerance to a wide range of soil fertility. It also has the ability to grow spontaneously under the cover of light-demanding tree species.

History and Introduction

The littleleaf linden is a native of Europe to Western Siberia and Iran. The tree dates back to 760 AD. 

Threats

Linden can colonize closed forests and out-compete native tree species for light and soil resources, leading to potential invasive dominance in the subcanopy and canopy. As this occurs, the species that depend on native tree species lose their essential food resources and decline.

This is particularly true for insects, which tend to be highly plant-species-specific in terms of food requirements for larvae.  At the ecosystem level, a decline in insects results in a decline in birds and other species. This adverse replacement effect is a growing concern as some of native forest species such as White Ash (Fraxinus americana) are decimated or eliminated by introduced insect pests.

Dispersal Methods

Tilia cordata can produce up to 1,000,000 seeds per year. Wind is the main vector for seed dispersal. The fruits generally fall very close to their parents, even in open areas. Seeds could also be dispersed by water, although it is very rare. Fruits and their bracts can float for a long time and can be carried by streams for relatively long distances.

Spreads through clump shoots and root suckering. Sprouts also grow very frequently from the root collar or, after cutting, from the tree stump. One sprout can replace an old or dying parent tree and thus prolong its life, even after the destruction of its trunk. In contact with the soil, branches may also develop roots and vertical shoots. Its exceptional ability to vigorously reproduce vegetatively makes it a quickly spreading invasive species.

Control

The most effective and easiest solution is the “hack and squirt” method. This involves making a chop into the bark with a hatchet in a downward motion then squirting in herbicide. Calling a professional arborist is also an option as they have access to injection herbicides that can be very effective.