Frankincense and myrrh are the resinous exudates from two genera, Boswellia and Commiphora, respectively, of the Burseraceae family. The trees produce resin as an immune response to heal and close their bark after natural or human-caused wounding. Frankincense and myrrh are two of the most ancient phytomedicinal resins and have woven their way through human history for millennia. Incense is mentioned in the earliest papyri of Egyptian polymath and vizier Imhotep (27th century BCE), and pharaohs sent ships to bring back frankincense and myrrh resins and live trees from the Land of Punt, which is assumed to be part of modern-day Somalia/Somaliland.1,2
The Bible repeatedly mentions frankincense and myrrh, which the three wise men, or Magi, gifted to Jesus at his birth. Other sources reference resins as being used for trade, sought as loot, and used as ransom payments, and over time, they became integral commodities in the first global trading routes.1 Traces of these resins have been found in archaeological and burial sites across the Arabian Peninsula, the Mediterranean, and northern Europe.3 Their medicinal uses have been recorded in traditional Indian and Chinese medicine for centuries. For millennia, their smoke has infused sacred rituals and churches,4 and resinous oils have been used to embalm the dead.5 These resins are fundamentally intertwined with the communities who live with, manage, and harvest them and the local and international traders and processors who buy and trade them.*
The genus Boswellia currently includes 24 recognized species,6 11 of which are found on the Yemeni island of Socotra. Though the trees and resins from these species have different local names, internationally, the generic name “frankincense” encompasses all their resins and resin products. With approximately 190 identified species in the genus Commiphora, debates are ongoing about which species constitute the myrrh referred to in ancient texts. Some Commiphora essential oils are more similar in composition to specific Boswellia essential oils, while others are more similar to Commiphora myrrha.7 It is still debated whether “myrrh” should be used as a trade name for only Commiphora myrrha or also for some other Commiphora species.
In many regions, frankincense and myrrh trees grow in the same arid and semi-arid ecosystems or Acacia-Commiphora woodlands and are equally vulnerable to drought, climate change, grazing livestock, fire, land-use changes, unsustainable harvesting practices, and felling for household uses.
Whether existing populations of Boswellia trees can sustainably meet global demand raises complex questions about the trees and their products. The purpose of this article is to discuss some of the key issues surrounding the management of frankincense trees, the communities who manage and harvest the trees, value chains, trade, and increasing use of frankincense, and to highlight some of the gaps in current knowledge. This article will focus exclusively on frankincense, with the understanding that some Commiphora species face similar challenges as frankincense trees.
The need to understand the current situation and identify workable, regenerative solutions has brought together scientists, exporters, distributors, trade associations, non-governmental organizations (NGOs), and representatives of national and governmental organizations in a number of recent international meetings. These meetings include the International Federation of Essential Oils and Aroma Trades (IFEAT) in Athens, Greece (2017), which provided an initial platform to debate the current situation, and the First International Conference on Frankincense and Medicinal Plants (ICFMP) in Muscat, Oman (2018), where more than 300 scientists, company representatives, and NGOs presented and discussed the problems and prospects for frankincense across a wide range of topics.† These two important meetings were followed by a smaller special session on frankincense and myrrh at the World Congress on Medicinal and Aromatic Plants (WOCMAP) in Bafra, Cyprus (2019), which also saw the emergence of the Global Frankincense Alliance (GFA),** which is described in this article.8
Also in 2019, parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) initiated an informal working group to gather information on the current status of frankincense trees and assess the need to mitigate threats to their long-term future.
Differentiating Species, Resins, and Resin Products
Geographically, Boswellia trees range from India, across the Arabian Peninsula, the Greater Horn of Africa, and across the Sahel (the transition zone of semi-arid short grasslands and savannas, just south of the Sahara Desert) to West Africa. While “frankincense” is the generic trade name for the resin as well as the trees of all Boswellia species, the conservation, sustainability, and socioeconomic issues that affect the different species and the aromatic, medicinal, and other uses of the resins differ significantly among each species and their habitats.9 One of the key messages from international meetings has been that recognizing this diversity is important to the future sustainable use of frankincense.
While, in general, Boswellia species grow in harsh arid and semi-arid environments and have adapted to be drought-tolerant and resilient, the growth patterns, adaptations, environmental conditions, management, and harvesting practices among, and even within, each species can be substantially different.10 New species continue to be identified. Difficulties of going to the source to collect botanical samples and identify different species, hybrids, and/or varieties have been highlighted with the emergence of B. occulta as a new species in Somaliland. For some time, despite the unique chemical profile and aroma of its essential oil, it was considered a chemotype (chemical type) of B. sacra until its leaves and fruits were further examined.11 At the same time, essential oil buyers may see both B. sacra and B. carteri on essential oil bottles. While they come from different geographical regions and have some significant differences that have created some debate,12 they are currently recognized as the same species.6 Additional niche species likely will be identified, and future comparative genetic and vouchered chemical analyses, as well as breeding and morphological studies of the 24 Boswellia species that are currently recognized, will assist in the search for markers to distinguish different species and their resins for scientific, conservation, regulatory, and quality purposes.
Increased Demand for Some Frankincense Resins and Essential Oils
Boswellia species have been used for millennia in traditional Chinese and Indian medical systems, and the past decade has witnessed increased scientific research on and knowledge about the potential therapeutic properties of some of these species as internal, topical, and aromatic products.13,14 The growing understanding of the medicinal properties of boswellic acids, which are found in commercially significant amounts in the resins of at least four species (Table 2), and popularity of frankincense essential oils in aromatherapy have led to increased demand for some frankincense resins and essential oils. Some market reports project the value of the frankincense essential oil market to double between 2018 and 2028,15 with a 7.7% average annual growth rate. Frankincense resin used for essential oil production is currently predominantly sourced from B. sacra in Somaliland, Puntland (Somalia), and Oman; B. serrata in India; and, to lesser extents, B. papyrifera, B. neglecta, B. rivae, B. dalzielii, and B. frereana.9 Increased demand for some frankincense resins for essential oil production and medicinal use is likely to affect each species differently across their geographical ranges, given the diversity of these species.
Sustaining the Trees and Communities that Harvest Them
To meet increased demand, more frankincense needs to be harvested and traded, but the actual sustainable production capacity of each species that will also allow the trees to regenerate is unknown. As current production is based on sourcing resin from a limited number of wild trees of these species, the immediate future of the resource depends on proper management, harvesting, and regeneration of current tree populations, but available data on each species vary.
Of the 24 recognized species, overharvesting for trade purposes is estimated to affect at least four species: B. sacra (syn. B. carteri), B. papyrifera, B. serrata, and B. frereana. Research shows that some of these key harvested populations are under severe pressure. This is notably true for B. papyrifera in northern Ethiopia and Eritrea,16 B. sacra in some areas of Somaliland, and reportedly for some populations of B. serrata in India.17,18 Research data on harvested and traded species often are sourced from accessible areas, which may also be subject to greater harvesting pressure, while remote and inaccessible areas may be less likely to have experienced pressure from human activities.25
For some other species and locations, regeneration currently does not seem to be an issue,26 but data are insufficient for several geographical areas and species, and confirmed data are scarce. At this time of projected increased demand, studies on harvesting pressure and regeneration have raised awareness and initiated the current push for greater collective action from landowners, communities, and harvesters who manage and know the status of the trees, as well as traders, exporters, international retail companies, and environmental and governance bodies. On the other hand, concerning findings in some heavily harvested areas have led to some generalized, sensationalized headlines in the popular press about the status of frankincense.27 Such headlines do not reflect the situation in all locations and certainly not of all Boswellia species.
In 2020, the secretariat of CITES collated the results of a questionnaire that was sent to relevant frankincense stakeholders asking for information on the biology and population status of each species, harvesting and supply chains, threats and intentional propagation, and current regulations and ownership structures.28 This initiated an active dialogue and helped bring attention to the need to not only fill the data gaps as soon as possible, but also think carefully about the most appropriate systemic changes needed to ensure the long-term future of the trees and harvesting communities.
Accurate Data Are Needed
Accurate data on the exact geographical range, population densities, and status of each species have yet to be gathered, perhaps because supply was assumed to sustainably meet demand and the trees were regenerating naturally in relatively inaccessible areas. By looking at historical data, mapping current knowledge, and layering climatic and environmental conditions that are likely to favor the different species, an updated map of the likely range of each species was published in Nature Sustainability in 2019.16 Increased expertise in calibrating complex satellite mapping of changes in dryland trees and woodlands can generate maps based on recorded observations and the likelihood of suitable and changing environmental conditions. This is especially helpful in some areas, like Dhofar in Oman, where frankincense trees are the predominant tree species of landscapes that are otherwise vegetation-sparse.
However, in other areas where frankincense trees do not represent the majority of vegetation, calibration of satellite data and verification on the ground (“ground truthing”) with sufficient numbers of survey plots are needed.29 Setting up and monitoring these can be costly and challenging in remote and insecure areas.
Because frankincense is a niche commodity and traditionally a secondary source of income, large-scale development-partner funding for reliably assessing the range, status, and health of frankincense trees can be difficult to acquire. Given the current push for integrated large-scale drylands projects,30 gathering this information as part of those project activities will support the development of focused conservation practices that can incentivize and enable harvesting communities to maintain healthy trees, as well as inform local, national, and international regulatory decision-making.
Harvesting and Management Practices of Different Communities and Stakeholders
A report by Munyua and Mbiru (2015) described Boswellia papyrifera, found in northern Ethiopia, as “overutilized,” and B. neglecta, B. rivae, and B. microphylla, which are all found in southern Ethiopia, as “underutilized.”31 Do some of the biological and morphological characteristics of each species determine how they are harvested and used? The quality and properties of individual species’ resins aside, the resin structures in the inner bark of B. papyrifera have been thoroughly researched to determine the most effective and sustainable tapping methods and healing cycles.32 However, B. neglecta and B. rivae grow in arid and semi-arid migratory pastoralist systems of the Somali region of Ethiopia and northern Kenya on mostly communally owned land and are “almost exclusively collected from the natural exudates without tapping.”33 Further research is needed to confirm if this is because the resin canals in the inner bark are structurally unsuited to the tapping techniques used and recommended for B. sacra, B. papyrifera, and B. frereana, or because of some other underlying reason(s). For B. papyrifera, increased tapping has been shown to allow greater longhorn beetle infestation and susceptibility,34 as well as reduced carbohydrate storage35 and seed reproductive capabilities.36 In Kenya, B. neglecta seems to depend on an interaction with the longhorn beetle larvae to produce its characteristic black resin, as its natural immediate exudate is very limited amounts of small white drops (H. Sommerlatte, Arbor Oils of Africa, email to S. Canney, November 18, 2021).††
The landscape can determine who harvests the resin. In Somaliland, where B. sacra trees can grow up to 8 meters (26.2 feet) tall, sometimes on dangerous cliff faces and dry rocks, men harvest and dry the resin and take it to collection centers where women, who often sit in the dust on the floor for long hours, sort it into grades. In the Samburu region of Kenya, groups of women walk together to scrape B. neglecta off much shorter trees that grow on hills close to savannahs, and this provides limited but direct income.
In Oman, Omani women and men previously harvested the resin from the trees,38 but now it is typically expatriate men. In Somaliland, as some landowners and their families move to urban areas, they may rent their trees to harvesting groups and traders.39
In the Blue Nile state of Sudan, communities reportedly gain no benefits from the trees.40,41 However, receiving direct benefits from the trees is key to engaging communities in comprehensive, long-term sustainable practices. The arid and semi-arid areas where frankincense trees grow are generally resource-poor regions. Besides livestock or subsistence farming, alternative livelihood options are few, so harvesting frankincense in the dry seasons can contribute significantly to otherwise-limited incomes.42-44
It is increasingly recognized that “the traditional supply chains of most resins can involve significant exploitation of the harvesters,”9 and investing in harvesting communities to support their development and incentivize sustainable tree management is a top priority to ensure the future of the trees and communities who harvest them.45 Also, these people often see very limited profit margins compared to middlemen and end product producers, and this can directly lead to unsustainable practices.46 “When harvesters are living so marginally, it can be difficult for them to make long-term, sustainably based management decisions,” noted the authors of a 2020 paper in The International Journal of Professional Holistic Aromatherapy.9
To ensure the future of frankincense trees, communities need to be engaged in many aspects of sustainable management. Depending on the species, management practices, and climate, trees are estimated to take up to 10-20 years to reach the trunk girth that is considered mature enough to start tapping and harvesting, although data are limited. Harvesters can threaten tree health by making too many cuts in mature trees too often and too deeply. However, conservation strategies that emphasize not harvesting resin from the trees may only be a partial solution, as the untapped live trees may then be vulnerable to being debarked or felled for medicinal use, timber, firewood, fodder, or land clearance.
In pastoralist dryland areas, where livestock are the main source of primary income, camels, cattle, and goats grazing on young saplings or shorter trees can be a major threat to woodland regeneration. In other areas, dry grass in open-canopy woodlands, where free-ranging cattle graze, can be intentionally or unintentionally burned, potentially destroying both seedlings and saplings. In these areas, community-based management of livestock and fire is an integral part of the long-term future of frankincense trees.
Land tenure systems, ownership, harvesting rights, and the prices harvesters and communities receive also become critical factors, which need to account for shifting social and environmental dynamics as well as the changing climate. In short, harvesters and harvesting communities have perhaps remained the least visible members of the value chain, and their knowledge, needs, and challenges must be heard and understood. Fostering incentives, working conditions, and supportive training and education to ensure sustainable harvesting practices is critical to the long-term future of the trees.
Investing in Propagation and Intentional Planting
Perhaps because wild trees traditionally have supplied the niche market for frankincense products, cultivation of Boswellia trees has been limited. Different species have different seed germination rates, and seed viability can also depend on the health of the tree.35 Some species with low seed germination rates, like B. serrata, propagate more easily from root suckers. With increased knowledge and improved techniques, intentional planting is likely to become a crucial part of longer-term conservation strategies. There are reports of plantations in Somaliland before 1991.47,48 Forest department records in India show that B. serrata was planted experimentally for paper, without much success.49 Consistent work with B. papyrifera root cuttings yielded better results.50 Other species, such as B. frereana and B. sacra, have adapted to specific environments, with the ability to absorb sea mists in otherwise hot and dry climates and grow on limestone with high-pH soils. It can take time to understand how to replicate the necessary conditions for resin production, particularly in other regions.
Jason Eslamieh in California, the Ministry of Agriculture and Fisheries in Oman, and Guy Erlich in Israel are pioneers in propagating, hybridizing, and intentionally planting trees of the genus Boswellia. Eslamieh has focused more on research and experimentation and published his decades of knowledge and findings of working with these plants in the United States.51 The Ministry of Agriculture and Fisheries in Oman has been planting and propagating B. sacra trees for more than 30 years, and plantations have expanded to a larger scale. Those working with the trees in Oman have begun sharing their in-depth knowledge of the planting, watering, care, and environmental conditions needed to allow the trees to mature.52 In Israel, Erlich has focused on the Balm of Gilead (Commiphora gileadensis) and B. sacra and has demonstrated that irrigated plantations can be established outside of current range states.53 The overall quality and quantity of resins from intentionally planted trees compared to resins from wild populations are still unknown.
Frankincense trees can be propagated intentionally on privately-owned plantations that prioritize frankincense resin production, or as part of the restoration and enrichment of existing trees and woodlands. Understanding the activities, outcomes, and consequences of the two different approaches is important, as each one is likely to have different effects for existing tree regions and the communities who currently use and depend on the trees and surrounding biodiversity.
Regeneration and new growth (whether wild or cultivated) depend on engaged sustainable management and the integrity of the forest. One supportive mechanism that focuses on the health of current forests and communities is voluntary third-party certification. Some voluntary third-party certifications focus on the health of the trees, fair payment, and living/working conditions for harvesters and can create greater confidence for consumers who are interested in buying sustainably harvested products. Wild-harvested Boswellia resin is intrinsically organic unless hormones are used to stimulate resin production.54 Organic certification can add value,55 yet this does not ensure single-species harvesting or long-term regeneration.
Conservation concerns raised in the international gatherings include the impacts of increased demand, armed conflicts, famine, increased human population, increased livestock numbers, better road access, and changes in land use and agricultural practices on traditional patterns of tree management, harvesting, and trade in some of the main frankincense-sourcing areas. To ensure sustainable management and regeneration of the trees, and to address some of these concerns, a broader approach and full community engagement are important. A summary of proposed solutions that now need collective action and investment was presented at the WOCMAP meeting in 2019 (Table 3).56
Using the Resins and Essential Oils
It can be surprising to learn of the many different species, phenotypes, qualities, colors, and aromatic profiles of the resins and essential oils of frankincense. Especially in Ethiopia and Oman, much frankincense resin is used in traditional and cultural practices instead of being exported. It is chewed as gum for its health benefits and burned to produce smoke as part of cultural, sacred, and/or personal hygiene rituals and practices.33,57
One of the most expensive frankincense resins is “Mushaad” — the first-grade slabs of B. frereana found on steep slopes in the highlands of Somaliland and Puntland (Somalia). Large fresh pieces traditionally have been sold in Saudi Arabia and Yemen as chewing gum and after-meal mouth fresheners. Significant quantities of B. papyrifera and other resins also have been exported from Ethiopia, Sudan, and Eritrea, often through Europe, as ritual incense for church services.57
The resin-production processes of the different species are not well studied. Whether the resin, which is produced in the inner bark, is constitutional (already available in the bark) or quickly produced upon natural or intended wounding, or both, is not well known. For B. papyrifera, constitutional resin is available in the resin canals and is drained upon wounding.32,58
Frankincense gum-resin usually contains three main components: gum, resin, and essential oils. The water-soluble gum often accounts for 6-30% of raw frankincense. The alcohol-soluble non-volatile terpene fraction can account for 60-85% and contains boswellic and lupeolic acids, which are being researched for their therapeutic properties. Essential oils often account for 1-10% and are a mixture of predominantly monoterpenes with diterpenes and sesquiterpenes.19
The percentages and ratios of these components can vary significantly among different Boswellia species, and the quantity and quality of resin harvested from one species can depend on the age and stem diameter of the tree, the number of current and previous harvests, and environmental conditions, including altitude, rainfall, sea mist, solar radiation patterns, nutrients, and insect and animal challenges.59 Natural variations among individual trees and populations of Boswellia species lie at the heart of current debates about trade standards, purity, quality, and regulation. Current understanding of the exact sources of and reasons for these similarities and differences is still limited.
More than 300 volatile compounds have been identified among Boswellia species. Two major limitations in our current knowledge of the constituents and compositions of frankincense essential oils are: Researchers are yet to understand the extent to which variation and different chemotypes of individual trees and populations of the same species are genetic (most likely) or due to other factors listed previously.
Many samples assessed in published papers are taken from markets, and the exact source of the samples is not always known. Some vouchered samples (resin samples that are connected to individual trees that are identified with an herbarium collection voucher) can produce outlying results, creating the need to look deeper. Differences could be genetic, yet may also be a result of different storage conditions, distillation methods, analytical techniques and libraries, and/or possible equipment contamination.
Variation across and within Species
Frankincense essential oils are now a common retail product. Understanding the normal composition of the oil of each species can be important for quality and regulatory purposes. Nevertheless, similarities and/or differences among species, as well as natural variation within species, can make it difficult to be certain that a particular oil comes from a particular species. As shown in Table 2, α-pinene, α-thujene, limonene, sabinene, and myrcene predominate in quite a few Boswellia species. General patterns for each species can emerge. For example, B. sacra from Oman usually has the highest α-pinene content (between 60% and 80%),9 but sometimes an individual Omani specimen can be lower.60
A few compounds may be unique to certain species. For instance, high levels of octyl acetate in B. papyrifera essential oil and methoxydecane in B. occulta essential oil are not known to be found at the same levels in other species.9 They can act as reliable identifying markers for those two species. When dominant terpenes are found across a number of species, researchers look for much lower amounts of a unique compound that could be specific to a particular species. Some possible markers and constituent patterns among species are emerging. Even so, it will take more in-depth research, using only vouchered specimens within and across populations and from different harvesting seasons, to be able to accurately identify the exact species of Boswellia that produced a particular composition of an unadulterated, species-specific frankincense essential oil.
Beyond issues of freshness, oxidation, and quality, causes of adulteration of frankincense essential oils can include species mixing, as well as intentional addition of key constituents from other species and sources.
Incentivizing transparent and traceable sustainable supply chains is another approach to support purity and quality standards. In some source regions, one frankincense species usually predominates, making it easy to harvest and track species-specific resin. Examples are India (B. serrata), Oman (B. sacra), West Africa (B. dalzielii), and northern Ethiopia, Eritrea, and Sudan (B. papyrifera). By contrast, in the Somali region of Ethiopia, northern Kenya, and parts of Somalia, where B. neglecta and B. rivae grow close to Commiphora species, harvesters can be aware of the different species but apply the same names to more than one species. For instance, “Midhafur” can be applied to B. neglecta, B. rivae, C. boranensis, and C. ogadensis in the Somali region of Ethiopia (Abdinasir Abdikadir, SoRPARI and Jigjiga University, email to S. Canney, June 2019). Harvesters need increased awareness and a value-added incentive to separate resins from different species. As the B. occulta story in Somaliland shows,11 an unidentified species can unwittingly be harvested under the assumption that it is a known species.
As the resins and oils of different frankincense species have different antimicrobial, antibacterial, and antifungal properties, species purity becomes critical for building consumer trust.14,61 Intentional adulteration of frankincense oil also needs to be watched carefully as demand increases. From a different point of view, some experts wonder if a frankincense-like oil that has the same medicinal and aromatic properties as a wild-harvested oil can be developed to take pressure off wild trees. But, would it be frankincense?
In traditional Chinese medicine, frankincense (ru xiang) and myrrh (mo yao) are thought to invigorate blood. Regarded as bitter and pungent, frankincense is believed to have a cleansing action on the body, moving qi (a vital life force), opening channels, clearing damp, and relieving pain.62 Shallaki, as B. serrata is known in the Ayurvedic medical tradition of India, mostly has been used to reduce inflammation and ease joint pain. Traditional herbal medicine often depends on synergistic actions among different herbs and resins, and frankincense and myrrh often are prescribed together.
Genetic pathways for the biosynthesis of boswellic acids remain to be identified, but researchers have analyzed the cytotoxic and anti-inflammatory mechanisms of boswellic acids in vitro and in vivo, along with the antibacterial, antifungal, anti-inflammatory, and other medicinal properties of different frankincense resins.
Incensole and incensole acetate, known to be found in the highest concentrations in B. papyrifera and B. elongata, have been shown in mice studies to have a robust neuroprotective effect after brain trauma and strong anti-inflammatory, antidepressant, and anxiolytic properties.63 Human clinical trials are still limited.13,14,59,64 Inhaling smoke65 and diffusing essential oil may have medicinal and mood benefits as well, particularly anxiolytic effects.14
Exactly how many bioactive boswellic acids remain after supercritical fluid (CO2) extraction of vouchered specimens has yet to be published. When distilling the resin using steam or hydro-distillation, there is no known evidence that these heavier lipophilic (fat-soluble) boswellic acids are taken up into the essential oil. They largely remain in the post-distillation residue. Nevertheless, preliminary reports of experimental cytotoxic effects of boswellic acids have led to some unsupported claims that steam or hydro-distilled frankincense essential oil can “cure cancer.”66 According to Abdul Latif Khan, PhD, an associate professor at the University of Nizwa in Nizwa, Oman: “We do not want to get to the point where pseudo-science and misinformation [are] used to sell the product.”39 Nevertheless, increased access to information on traditional medicinal uses, in vitro and animal study results, and proposed research on B. sacra and B. serrata for different types of cancer and COVID-19 remediation67 could lead to increased popular demand.
Compared to traditional medicinal uses of the whole resin or infusions, the growing therapeutic use of distilled essential oils is relatively recent. Even so, there is an increasing body of in vitro and in vivo experimental results on the bioactivity of frankincense essential oils, particularly antibacterial, anticancer, antifungal, anti-inflammatory, antioxidant, insecticidal, and larvicidal properties.68-70 Frankincense oil is regarded as relatively “safe” in terms of topical allergenic and phototoxic properties.71 More systematic research is needed to understand and support the current medicinal and therapeutic claims of the benefits of vouchered essential oils of each frankincense species.
Frankincense plays a large role as a natural perfumery ingredient. Some of the signal aromatics, such as the musty “old church smell,” may arise from small percentages of heavy sesquiterpenes and diterpenes such as olibanic acids. Nicolas Baldovini, PhD, of the Institute of Chemistry of Nice, France, summarized some of his main olfactory findings at the special session at WOCMAP in 2019 (Table 4).
Key Trade Issues
At international gatherings, discussions about frankincense trade and markets also have raised important issues. For example, it is difficult to evaluate the complexities of some value chains and access and collate trade data (including volumes and accurate import and export figures). Two other issues are standardization and expanding the portfolio of frankincense retail products and uses.
Given natural variations, would standardization expand or limit market availability of genuine pure frankincense products? National and international trade regulations do not always focus on specific Boswellia species themselves. They often use a generic code for Boswellia resins and resin products. However, frankincense resin is usually sold as species-specific. But, frankincense essential oil can be either a blend of essential oils from different Boswellia species or an essential oil from one Boswellia species. As shown in Table 2, the essential oils of different Boswellia species can have similar or distinct dominant terpenes, and individual species can have different chemotypes.21,22 Because of natural variation, the individual terpenoid content of the essential oil of any one Boswellia species needs to be accurately expressed as a range of percentages, unless referring to one specific batch composition.9 Some traders have determined their own desired constituent ranges of the most popular frankincense species’ essential oils, even if it means rejecting and maybe limiting market availability of some genuine vouchered oils. Other retailers are happy to integrate natural variation in their business models and treat each vouchered species-specific batch more like a vintage wine.
As mentioned previously, more work is needed to analyze the similarities and differences in terpenoid composition across a broader range of vouchered samples from different trees and locations of the same species and among different species. As so little is currently understood about the reasons for differences in the compositions of gum-resin and essential oil among individual trees and populations, setting even species-specific essential oil standards is probably a less effective way to support regenerative tree populations and harvesting communities than advocating for transparent supply and value chains.
Adding Commercial Value to the Whole Resin and Byproducts
Over the past 10 to 15 years, essential oil distilled from whole resin has received more commercial attention than the raw resins. Given that essential oil constitutes between 1% and 10% of the resin (Table 4), can the rest (“waste”) be used in or transformed into byproducts, making the resin even more valuable? With little research published so far, experts disagree on whether and how many useful boswellic acids remain in the post-distillation resin from key species.19 Some of the molecules that account for frankincense’s “old church smell” are heavy and may also remain in the post-distillation resin, creating opportunities to use it as incense.
The hydrosol (distillate water) gathered from the distillation of different species can have a pleasant aroma and contain up to 700 mg/L of hydrophilic (water-soluble) volatile compounds, with verbenone and terpinen-4-ol often predominating.72 Using and selling the hydrosol commercially as perfumed water or mists could allow greater value to be derived from the resin. One important trade issue will be to extend the registration of different products from different Boswellia species for various cosmetic, consumable,73 and medicinal uses in different markets.
Transparent Supply and Value Chains
During the international gatherings, it also became clear that the ethics of the supply chains of importing companies have a large role to play in the sustainable future of frankincense and are deeply dependent on the contextual realities and activities of the harvesters, middlemen, and traders. Traceability is made more complex as middlemen and traders often aggregate resins from different sources within a country into larger single lots, many of which are intended for export. At the same time, shorter, more transparent supply chains with fewer middlemen are expected to lead to more direct benefits for communities and/or smaller-scale range state businesses. Also, more end-users are demanding equitable and sustainable supply chains.74
As mentioned, third-party certification of sourcing practices and supply chains can support sustainability, as has been shown for other commodities such as timber, coffee (Coffea spp., Rubiaceae), and chocolate (derived from Theobroma cacao, Malvaceae). Harvesters and harvesting communities often receive relatively little income from raw forest products and can rarely afford the upfront and ongoing costs of voluntary or regulated certification. These realities can push pricing and buying power into the hands of larger brokers and commercial entities whose approach and commitment to sustainability become all-the-more critical to the survival of the trees and future supply of resin.
In some areas, harvesters are being supported to form cooperatives to share best practices, act as centers of intentional propagation, stabilize prices, and gain more reliable access to markets. In the future, as phone connectivity spreads to currently inaccessible areas, taking photographs of tapping practices, marking GPS locations of harvested trees, and sending that information or capturing it in emerging technologies, such as blockchain, will provide a verifiable record.75 Digital payments will allow for more direct verifiable remuneration of harvesters. This level of diligence may add additional upfront costs, especially for small-scale businesses, but will add little to retail prices when scaled out. The additional brand value created by confirming sustainability is likely to outweigh any additional retail cost and meet the needs of consumers who want to ensure sustainable sourcing.
Creation of the Global Frankincense Alliance
The future of frankincense relies on the support of a wide range of stakeholders, who each play a part in ensuring sustainable trade. Given uncertainties, complexities, and unknowns in this commodity market, some delegates at the meeting of WOCMAP in Cyprus in 2019 suggested creating a lean international platform for the collection and dissemination of information on taxonomy, scientific discoveries, conservation issues, industry activity, new legislation, and trade developments in this sector. In response to this request, concerned scientists and other interested parties established the Global Frankincense Alliance, a nonprofit organization and platform, in 2020.
In March 2021, the GFA organized an online workshop, “The Future of Frankincense,” which had more than 300 registered delegates from 38 countries. Many participants filled out an initial questionnaire, and the purpose of the meeting was to collectively explore the most important questions that need to be answered and actions that need to be taken to support the long-term future of frankincense trees and the communities that harvest them. The workshop had four major themes: (1) Botany, identification, and current status of the trees; (2) Communities, regeneration, and forest management; (3) Biochemistry and medicinal applications; and (4) Supply chains, products, regulations, and trade. The virtual gathering made it possible for farmers, traders, and harvesting community representatives in range states to participate and report back directly on range state focal group meetings. The full report is available on the GFA website.39
It is challenging to gather and provide international regulatory bodies such as CITES with adequate, scientifically verified evidence on the status of the different species and information about supply and value chains and international trade — all of which are needed for making effective decisions. Much of the knowledge of the status of frankincense trees currently lies with people and organizations that harvest from and manage the trees and private-sector stakeholders that are directly involved in trade. Some of this is reflected in scientific reports, but many of these reports are not publicly accessible. Multi-stakeholder forums, collaborative projects, and working groups, where researchers and public and private organizations share information about frankincense, have become more important for identifying and promoting effective species-specific sustainable practices.
The authors would like to thank the Global Frankincense Alliance Advisory Board and Chairperson Anjanette DeCarlo, PhD; Stephen Johnson of FairSource Botanicals; and Eng. Salah Ajeeb, frankincense agronomist in Salalah, Oman, for their support.
Sue Canney Davison, PhD, grew up in northern England and has lived in India and in Kenya for the last 28 years. Her career has focused on facilitating diverse collaborations and knowledge creation across many organizations and countries. Her passion for Burseraceae trees and harvesting communities started in Kenya in 2012. She actively supported the Global Frankincense Alliance (GFA) between November 2019 and April 2021, including “The Future of Frankincense” online gathering in March 2021. As a research associate in the Department of Botany and Plant Biotechnology at the University of Johannesburg, she continues to study the Burseraceae family.
Frans Bongers, PhD, is a professor of tropical forest ecology at Wageningen University & Research (WUR) in the Netherlands and focuses on succession, biodiversity, forest regeneration, and forest management in various tropical countries in Africa and Latin America. He is a world-leading expert on the sustainable use and management of frankincense trees. For 20 years, he has studied frankincense populations in Eritrea, Ethiopia, and Sudan and has authored or co-authored more than 35 publications related to frankincense. As a board member of the GFA, he strives to improve sustainability in the worldwide frankincense production chain.
Denzil Phillips, MSc, has worked for more than 30 years in the field of medicinal plant conservation and sustainable sourcing. He has had consultancies in more than 35 countries in Europe, Asia, and Africa, and has worked with some of the world’s leading development agencies and natural products manufacturing companies. Denzil has done pioneering work with threatened plants such as Taxus baccata, Aquilaria malaccensis, and more recently, Boswellia sacra. He is a founding member of the Association for African Medicinal Plants Standards (AAMPS) and the GFA.
* More information about this aspect of the frankincense trade can be found at www.globalfrankincensealliance.com/articles-and-reports-history-and-culture.
† ICFMP abstracts are available on GFA’s website.
** As of January 2022, the Global Frankincense Alliance (GFA) was reorganized to better achieve its original goal to create an independent platform where scientists, experts, and stakeholders in the frankincense sector can share information and learn together. To achieve this, the GFA will now operate under the umbrella of the conservation and research project Save Frankincense (www.savefrankincense.org). GFA’s aims, objectives, and website (www.globalfrankincensealliance.com) will remain unchanged.
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