Prunus serotina

Prunus serotina is a medium-sized, fast-growing forest tree found throughout the Americas. It is commonly known as the black cherry, or sometimes as wild black cherry, rum cherry, or mountain black cherry. This tree belongs to the Rosaceae family, which is the rose family. Although it shares a name with common orchard cherries, it is not very closely related to them. Black cherry is considered a pioneer species. This means it is often one of the first trees to grow in new areas like old fields or forest margins. It thrives in sunlight and often grows alongside other species like black walnut and hackberry.

The physical appearance of the tree changes significantly as it matures. For its first ten years, the bark is thin, smooth, and banded. During this stage, it may resemble a birch tree. As the tree reaches maturity, the bark becomes very broken and turns a dark gray to black color. The leaves are long and shiny with finely toothed margins. In the autumn, the foliage changes color to shades of yellow or red. The tree produces small, white, five-petalled flowers. These flowers grow in long clusters called racemes, which contain several dozen individual flowers.

Black cherry trees use a sophisticated biochemical defense mechanism to protect themselves from herbivores. The plant produces compounds called cyanogenic glycosides, such as amygdalin. These compounds can be converted into hydrogen cyanide, which is a poisonous substance. If you scratch a young twig, it releases an almond-like odor due to minute amounts of these compounds. The seeds of the black cherry contain these glycosides. When the seed is ground or minced, it releases enzymes like amygdalin beta-glucosidase, prunasin beta-glucosidase, and mandelonitrile lyase. These enzymes break down the compounds to release hydrogen cyanide. While the fruit flesh contains these glycosides, it lacks the necessary enzymes to convert them, making the flesh safe to eat.

This chemical defense also exists in the foliage, especially when the leaves are wilted. Because wilted leaves can release hydrogen cyanide, they can be dangerous to livestock. Farmers often have to remove fallen trees from grazing fields to prevent animal illness. In some cases, trees grow in such large numbers along fencerows that monitoring every fallen branch is difficult. Interestingly, some insects have adapted to this defense. The eastern tent caterpillar, or Hyphantria cunea, can inhibit the impact of cyanide in the leaves. It does this using its alkaline stomach acid.

The ecology of the black cherry involves a complex relationship with local wildlife. The tree produces reddish-black fruits known as drupes. These fruits are a vital food source for birds and bears. As these animals eat the fruit, they disperse the seeds through their waste. All Prunus species have hard seeds that benefit from scarification. This is a process where the seed coat is worn down to help germination. In nature, this often happens after a seed passes through an animal's digestive tract. Some seeds may stay in the soil bank for as long as three years before they germinate.

Beyond animals, the tree supports a massive variety of insect life. Prunus serotina hosts the caterpillars of more than 450 different species of butterflies and moths. Notable examples include the eastern tiger swallowtail, the viceroy, and the red-spotted purple butterfly. It also supports various moths, such as the cecropia, the polyphemus, and the wild cherry sphinx. The tree is quite hardy and can tolerate poor soils and even oceanic salt sprays. It is a moderately long-lived species, with some trees recorded at 258 years of age. While fruit production begins around age 10, heavy production typically starts at 30 years and continues for over a century.

Humans have utilized the black cherry for many different purposes throughout history. In pre-Columbian Mexico, the variety known as Prunus serotina subsp. capuli was cultivated. It was known as capolcuahuitl in Nahuatl and served as an important food source. Native Americans also consumed the fruit, which can be eaten raw or made into jelly. The juice is sometimes used as a drink mixer, which is why it is called the "rum cherry." Additionally, the timber is highly valued in the United States for cabinetry. High-quality cherry wood is known for its tight grain and strong orange hues. In the mid-20th century, the tree was introduced to Europe as an ornamental plant. However, it has since become an invasive species there, affecting the biodiversity of local forests.