Three prominent North American plants to discuss in the context of their medicinal bark use are Populus tremuloides, Frangula californica subsp. Californica, and Amelanchier alnifolia. In addition, the South African native Dovyalis caffra and the Chinese native Rhaphiolepis umbellata can also be discussed in relation to these North American trees, revealing fascinating histories of neocolonial cooption, commercial exploitation, and indigenous erasure over the past several centuries of European hegemony.
Populus tremuloides, otherwise known as the quaking aspen, is part of the Salicaceae family and is native across much of the North American continent. P. tremuloides can be found across Canada and the United States in states as diverse as New Mexico and New York. This deciduous tree has a long trunk with smooth bark and fluffy catkins that grow from the branches. During the fall, the wide sage leaves may appear orange or yellow before being shed. However, the bark of Populus tremuloides has historically been used for its medicinal properties, as the bark contains salicylates, a property used to create aspirin. Indigenous communities like the Apache, the Blackfoot tribe, and the Navajo tribe rely on the bark of this plant to relieve pain from menstrual cramps, combat digestive issues, treat coughs, fevers, and even arthritis. The bark has further been used for its anti-inflammatory and antiseptic medicinal properties, mainly in treating wounds and respiratory disorders when used externally rather than consumed (Simpson 2010, 55).
Another tree found at the UCLA Botanical garden within the family Salicaceae, Dovyalis caffra or the Kei Apple tree, could be analyzed in its stead. Despite being part of the same family, Dovyalis caffra has many phenotypic differences from Populus tremuloides. For instance, D. caffra has much brighter and narrow green leaves with yellow flowers, is native to South Africa and is much shorter than the tall Populus tremuloides trees in the northern hemisphere. Despite their clear morphological differences, both Populus tremuloides and Dovyalis caffra contain a class of chemicals known as salicylates, a naturally-occurring pain reliever and chemical precursor to modern-day aspirin. When boiled into a tea and ingested, bark from both plants may be used to treat pain from illnesses like rheumatism (Anderton 2011, 4).
Another plant that has been used by indigenous communities for the medicinal properties it serves is Frangula californica subsp. Californica. Frangula californica subsp. Californica also known as the coffeeberry, is an evergreen or semi-deciduous shrub in the buckthorn family that is native to California and can be found in other regions of Western America. This plant can be identified from its small, dark green leaves that range from ¼ - 3 inches in length and the presence of blooming coffee berries in the summertime. As a shrub, the plant ranges in height from 3 to 12 feet. The blooming season begins with small white/green flowers and gradually evolves into small clusters of berries that become deeper in purple hue over the summer. Indigenous tribes of California have been utilizing this plant for centuries, including the Ohlone, Chumash, and Kumeyaay tribes who celebrated and made use of the specie’s healing properties. Indigenous Californian tribes dried the inner bark of Frangula californica subsp. Californica and ground it up to create a tea that's served as a treatment for constipation due to its “purgative effect”, as well as a kidney remedy and influenza treatment as a result of proven antimicrobial properties.
Finally, the serviceberry bush, Amelanchier alnifolia, is a case study in Indigenous cultural erasure for the benefit of Western aesthetics. Classified as a member of the family Rosaceae family and Amelanchier genus, this shrub consists of leaves that are a dark green and ovate in shape with serrated leaf margins. Clusters of radially symmetrical, 5-petaled white flowers grow on racemes that emerge from the terminal branches. This species is commonly found in temperate regions of the Northern hemisphere from eastern Alaska through most of Western Canada and as far south as Oregon and South Dakota, across a wide range of altitudes and soil types.
Due to its expansive range, Amelanchier alnifolia is integrated into the ethnobotanical practices of many Indigenous groups across the Pacific Northwest, the Great Plains, and Canada. The Blackfoot Native America tribe used this shrub for food due to the berries it produces and for its medicinal properties. It has been used for appetite restoration, as a laxative, in the treatment of upset stomachs, for treatment of colds, to treat chest and lung infections, and to induce a fever to restore one back to good health. According to McCutcheon, decoctions of saskatoon bark were commonly employed by “traditionally used to treat respiratory ailments such as colds and coughs, as well as diarrhea, influenza and smallpox” (McCutcheon et al, 1995, 106).
Rhaphiolepis umbellata is a fellow member of the family Rosaceae, sharing many morphological similarities to Amelanchier alnifolia with a vastly different native distribution. Commonly found in subtropical forest regions of East Asia, encompassing vast swaths of China, South Korea, and the Japanese archipelago (Abe and Matsunaga, 2011). Similarly to A. alnifolia, R. umbellata is a dense woodland shrub with glabrous branches and ovate green leaves; unlike its relative, however, this species is incapable of taking on a tree-like growth habit and is evergreen rather than deciduous. Flowers of both species are similar and typical of the family Rosaceae: 5-petaled, white, with a cup-shaped calyx and spirally arranged stamen. This species has attracted significant attention in the 20th century as a low-maintenance ornamental plant in urban landscaping projects across much of the Northern hemisphere. Similarly to Amelanchier alnifolia, R. umbellata has been extensively investigated for the presence of flavonol glucosides sourced from bark-based concoctions, which hold potentially cytoprotective benefits when consumed (Nonaka et al, 1983).
All of these plants that share medicinal properties in their bark that can be consumed through tea are unfortunately subject to modern commodification that threatens to rewrite Indigenous history in the name of commercial interests: for instance, monocrop farming of biomedically-valued tree species involves the elimination of less profitable local species, thus limiting access to these plants as sources of food, raw materials, and medicine (Turner, 2001). In order to protect Indigenous cultural sovereignty, further research and harvesting operations involving traditionally-utilized plants, including all species examined above, must be performed in collaboration with tribal leaders in accordance to community needs and values, creating a coproductive and mutualistic future for all parties involved.