The Next Miracle Tree: Tea Tree and Its Relatives

Any plant product that’s touted as “nature’s miracle healer” and “medicine chest in a bottle”, as tea tree oil is on the American market, garners more than the normal degree of skepticism from this herbal curmudgeon. So when I traveled to Australia in the fall of 1992, one of my goals was to unlock the mystery of the tea tree: what it is, where it came from, how it’s perceived Down Under, and what all the hoopla is about. Of all the claims made for this plant, which are supported by fact and which are commercial hype?

In Australia, “tea tree” has long been a generic term for the aromatic trees of the myrtle family (Myrtaceae), especially the genera Melaleuca and Leptospermum, which abound in Australia and whose leaves are popular in beverage teas. Soon after my arrival, I attended a wild aboriginal food extravaganza in Neilson Park in the eastern suburbs of Sydney. The indigenous haute cuisine, which included emu sausages, pippies (a clamlike shellfish), kangaroo jerky, roasted moths, and witchetty grubs (large moth larvae), was washed down with a delightful lemon-flavored tea made from the leaves of the lemon tea tree (L. petersonii).

In international commerce, tea tree has come to refer to just one species, M. alternifolia, a shrub or small tree that grows to 18 feet tall. Like other members of the genus, it has a papery bark. The leaves are alternate, as the species name implies, and they’re less than 1/8 inch wide and rarely more than 3/4 inch long, tapering to a point at both ends, which makes the tree look like a short-needled conifer. During the summer, the cream-colored flowers form in loose spikes that resemble bottlebrushes. The nearly exclusive native range of this subtropical species is an area of about 100 square miles in the northeastern corner of New South Wales (north of Port Macquarie) and in southern Queensland, generally in swampy or wet ground.

Myrtle family members are as ubiquitous in Australia as are pines in the northern United States or oaks in the South. Australian forests contain hundreds of species of Eucalyptus, sixty or more of Melaleuca, and about twenty of Leptospermum. Among the many aromatic plants in Australia, M. alternifolia is second only to eucalyptus in economic importance. It probably could be grown in other subtropical regions of the world, including the extreme southern United States, but Australia protects this valuable asset, and people have been jailed for attempting to leave the country with propagation material.

Selling the Cure: The Early Years

During the late nineteenth century, when patent medicines were in their heyday, the Ti Ta Volatile Oil Company of Brisbane marketed a product called Ti-Ta which they claimed “cures all diseases”. The only ingredients listed on the label were oils from “a tree, moss, and fern indigenous to Northern Queensland.” Ti-Ta enjoyed only a short commercial life, and it might not even have contained M. alternifolia oil, but it set the stage for future development of Australia’s “ti tree”, later called tea tree.

Although research on its effectiveness was limited and the results were not definitive (see “The Scientific Record”, page 50), the late 1930s saw an increase in the use of tea tree oil, primarily in Australia, as a disinfectant in soaps and as a topical treatment for parasitic skin diseases; a glass of water with a couple of drops of tea tree oil was considered an excellent gargle for relief of sore throats in the early stages of inflammation.

Its confirmed antiseptic activity, apparent lack of toxicity, and gentleness on mucous membranes (when sufficiently diluted) eventually gave the oil a temporary foothold among Australian dentists. The more adventuresome among them began using a product called Melasol (essential oil of melaleuca in aqueous suspension) to treat several forms of gum disease. Some general practitioners used the oil in treating throat infections, dirty wounds, and fungal infections such as ringworm, athlete’s foot, and candida.

The commercial success of tea tree oil was tentative at best, partly because the source of supply was limited and partly because the oil varied widely in quality. The leaves had to be harvested from wild trees, and efficient harvesting was hampered by the trees’ location in wet areas. A company called Australian Essential Oils extracted most of the country’s supply by setting up stills in the swamps.

In spite of these problems, the oil managed to sustain commercial interest through the Second World War. Australian soldiers deployed to tropical regions carried it in their first aid kits as an antiseptic and to combat fungus infections. In ammunition factories, it was added to machine cutting oils to reduce infection from injuries caused by metal filings and turnings. After the war, however, the use of tea tree oil gradually declined with the proliferation of antibiotics. Only a handful of stills remained in operation to supply oil for limited commercial applications. By the mid-1970s, years of poor harvests and wide variation in supply and quality, coupled with a marked lack of promotion, led to nearly complete dissolution of the Australian tea tree oil industry.

At about that time, Christopher Dean, a young entrepreneur, and his family took a new tack: they began cultivating M. alternifolia on a plantation near Bungawalbyn Creek in northern New South Wales, where the tree was growing wild. By the early 1980s, they were bottling their own tea tree oil and selling it through pharmacies and health food stores throughout Australia. Part of the Deans’ success came from hard work and part from luck and timing, but it was their slogan, “a medicine chest in a bottle”, that soon caused the market to explode. In 1985, ten metric tons of the oil was produced in Australia, and a year later, the newly formed Australian Tea Tree Industry Association boasted more than sixty members.

The association brought credibility to the product and the industry and thus paved the way for growth in international markets. Production studies and clinical and toxicity trials followed, and a national quality standard was developed. This standard focuses on the amounts and proportions of two major components of tea tree oil, terpinen-4-ol and cineole, which vary significantly among M. alternifolia trees grown in different parts of its range. (Cineole is the primary active ingredient of eucalyptus oil.) The minimum standard requires that tea tree oil contain at least 30 percent terpinen-4-ol and less than 15 percent cineole. Oils containing as much as 47 percent terpinen-4-ol and as little as 2.5 percent cineole are rare but considered to be the best; those high in terpinen-4-ol and low in cineole appear to produce the greatest and most predictable bactericidal activity, and cineole-rich oils are more likely to cause skin irritation. Wild tea trees growing near the southern limits of their range tend to be relatively rich in cineole, and their oils are less sought after.

Today, the Australian Tea Tree Industry Association certifies oil quality and the authenticity of the M. alternifolia source.

Selling Tea Tree in America

During the past decade, especially since oil quality has become more consistent, melaleuca has become one of the few herb products on which entire companies base their product lines.

Melaleuca products appeared on the American market in the early 1980s, a few years before the Australian quality standard was developed. The oil and its products quickly became widely available from established distributors of medicinal herbal products as well as by direct marketing. During the past decade, especially since oil quality has become more consistent, melaleuca has become one of the few herb products on which entire companies base their product lines. The oil now abounds in every product category in which essential oils are commonly used: topical first aid preparations; medicated shampoos, hair rinses, and conditioners; toothpastes and polishes; mouthwashes and throat sprays; hand and body lotions, facial cleansers, lip balms, and sunscreens; douches, laundry soaps, perfumes–the list goes on. The mere presence of tea tree oil in these products seems to enhance their commercial value, even when the oil is listed under “other ingredients” on the label and the quantity is minute.

In 1990, a marketing company called Melaleuca, Inc., ranked 37th on Inc. magazine’s list of the 500 fastest-growing American private companies. Melaleuca has become big business: Australian plantations in what is now known as the Bungawalbyn Reserve are expanding rapidly, and production and demand estimates for 1998 exceed 700 metric tons.

The Next Miracle Tree

Now, a year and a half after my journey to Australia, I feel I’ve found the answers to most of my questions about tea tree and its oil. The oil is unquestionably a promising therapeutic agent because of its proven antibacterial properties, and it has shown some promise in treating numerous common, relatively minor conditions. Its safety, though not scientifically confirmed (see “The Scientific Record”, page 00), is relatively well established through long usage, and it has myriad uses in cosmetics, soaps, and other commercial products.

However, the same and more can be said of a hundred other herbs that have not enjoyed a fraction of the commercial success of tea tree oil. There seems to be something irresistible about this exotic plant that grows only in a small area of Australia. This may be the true miracle of the tea tree, and the source of the present public excitement about it: the miracle of marketing and public relations.

Might there soon be another herbal success story of this magnitude? Savvy entrepreneurs might do well to consider the American sweet gum tree (Liquidambar styraciflua), whose essential oil is similar to that of the tea tree but surprisingly has not been developed commercially. A recent study–in Australia, as a matter of fact–showed that the essential oil of sweet gum leaves contains more than 30 percent terpinen-4-ol and only trace amounts of the undesirable terpenoid cineole. Move over, tea tree: make room for sweet gum oil, the miracle from America!

Steven Foster is an herbalist, writer, researcher, and consultant based in Eureka Springs, Arkansas.

Trouble in the Everglades

America’s melaleuca story has a dark side. Of the many species of melaleuca, one, the cajeput tree or broad-leaved paperbark tree (M. quinquenervia), has become the nemesis of south Florida. Travel along any highway there, and you can’t help noticing the expansive thickets of eucalyptuslike trees with thick, peeling, papery bark.

About 1890, the United States Department of Agriculture (USDA) in Florida ordered cajeput seeds from France. In 1906, Dr. John Gifford, a Miami forester, obtained seeds. These seeds were planted experimentally in swampy areas of south Florida in the hope that the trees would dry out the soil sufficiently to make it usable for agriculture or housing. A secondary part of the plan was cajeput’s commercial development: it is an oil-producing plant, a source of decorative wood, and a fast-growing ornamental landscape plant.

In 1908, cajeput was being grown successfully at a USDA Plant Introduction Station near Coconut Grove, Florida. The station relocated a few years later, and the established cajeput trees stayed and reproduced. Like kudzu, cajeput’s growth characteristics and reproductive cycle, together with a lack of natural controls, allowed populations to run amok, and the tree is now a major ecological threat to important south Florida natural areas including Everglades National Park, Big Cypress National Preserve, and the Loxahatchee National Wildlife Refuge. Cajeput is more adaptable than was originally supposed; it thrives in relatively dry as well as moist habitats. It grows in dense thickets, eliminating most forms of native vegetation, and it has now invaded three of the four major ecosystem types in south Florida–saw grass prairies and mangrove and cypress swamps.

Early attempts to control cajeput by burning only exacerbated the problem. The tree’s thick, spongy, protective layered bark is resistant to fire, but even after being burned, the tree quickly resprouts. Fire also causes the hard, buttonlike seed capsules to burst open, releasing millions of tiny seeds which are then dispersed by wind and water. Florida’s Melaleuca Task Force, which issued a Melaleuca Management Plan for South Florida as recently as 1990, noted that “the uncontrolled expansion of melaleuca constitutes one of the most serious ecological threats to the biological integrity of South Florida’s natural systems.”

The development of commercial uses for cajeput has been equally unsuccessful, at least in Florida. The highly aromatic cajeput tree does produce an essential oil, but its chemical composition resembles that of eucalyptus oil more closely than it does the oil of M. alternifolia. Cajeput oil averages 40 to 65 percent cineole, and it has been used like eucalyptus oil as a stimulant, antispasmodic, and germicide as well as a fragrance; externally, it has been applied as a counterirritant for treating rheumatism, neuralgia, gout, sprains, and bruises, and has been inhaled for bronchitis and pneumonia. In the Far East, cajeput was planted for commercial production of the essential oil, which was used to treat cholera and diarrhea until it was replaced by more modern medicines. But the Florida cajeput populations have never been developed as a commercial source of essential oil, and probably never will be.

The hard, close-grained wood of caj­eput resists rot in contact with the ground, which has made it useful for wharf pilings and railroad ties. Cured slowly so that it doesn’t crack, the wood has a beautiful dark finish with sprays of light wood rays; its appearance has been compared with that of mahogany. This quality makes the wood suitable also for carvings, furniture, and gunstocks. Cajeput also makes excellent firewood, and its pulpy, spongy bark has been harvested on a small scale for use as an absorbent material in the florist trade. Yet despite all this potential, none of the many attempts to develop an economic use for cajeput have come to fruition. The threat to millions of acres of Florida’s natural areas seem to outweigh the value of cultivating it in this country.

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