The inner bark of species traded under the Portuguese name ‘pau d’arco’ are now placed in the genus Handroanthus, with their formerly widely used Latin names in the Tabebuia genus now considered synonyms. These towering deciduous trees with beautiful flowers, purple, yellow, and pink, depending on the species, are native to tropical regions of the Americas. The Handroanthus genus has about 353 species. They are slow-growing trees and are considered some of the most vulnerable species to logging in Amazonian forests because of their low density and slow growth rates.
The inner bark of two species primarily traded for use in herbal medicinal products, are Handroanthus impetiginosus (syn. Tabebuia impetiginosa), which is the pau d’arco of Brazil, and Handroanthus serratifolius (syn. Tabebuia serratifolia), which is the tahuari of Peru. Popular common names for the species include pau d’arco, taheebo, lapacho, tahuarí, tajibo and ipé. The Portuguese name ipê seems to be most popular when the species is used as a source of timber and ornamentals. Pau d’arco is most commonly used when the medicinal uses are being considered (1).
Medicinal use of pau d’arco
The pink or purple flowered pau d’arco (H. impetiginosus) is typically used in the European and US herbal products markets. Though the most common species in trade, different Handroanthus species are found in ethnomedicine, like the yellow flowered pau d’arco (H. serratifolius) native to South and Central America, are considered to be similar biochemically, each producing lapachol, and are likely to be similarly efficacious (2).
The inner bark of pau d’arco is the part used as medicine and is believed to be antiseptic, anti-inflammatory, and anti-tumoral. Pau d’arco has been used by several groups of indigenous peoples in South America for a variety of conditions including stomach aches, fevers, colds and flu (the leaves), leishmaniasis, dysentery, and (with other species) diabetes. Others report use for “various maladies, especially cancer,” as an astringent, and for liver cirrhosis (3).
The inner bark of yellow pau d’arco, much like other species of the Handroanthus genus, is a natural source for lapachol, a compound that has been studied for anti-inflammatory, anticancer,antiparasitic and immune-modulating activities (4).
Pau d’arco in the logging industry
Pau d’arco trees, generally referred to as “ipê” in trade, produce very hard, heavy, durable wood that is highly valued in the market. It is sold locally for constructing houses, bridges, flooring, decking and handicrafts. Internationally it is primarily used for decking (5). The inner bark used for medicinal products on the international market Is a by-product of the logging industry.
Once the trees are logged, they are floated by river to urban areas for further processing. Because the wood is so heavy, buoys are used to keep it from sinking (6).
Brazil is the highest exporter of ipê, which are some of the most expensive species used in logging on the market in Brazil. The timber is referred to as the ‘new big leaf mahogany’ (Swietenia macrophylla), which was listed on CITES because of declines from overharvesting. This has increased the price and demand for ipê and led to its listing in CITES Appendix 2 as well. The US and European countries are the main importers. There are no plantations of ipê and so all of this wood comes from natural forests. Over harvesting of the trees and deforestation from demand for agricultural land are the major threats. Habitat loss from fires, development, and conversion to pastures for livestock also threaten the species (7).
Over 525 million kg (or 469,613 m3) of ipê timber products were exported from Bolivia, Brazil, Paraguay, and Peru between 2017 and 2021. Most ipê is exported from Brazil, which accounted for 96% of the trade (based on volume). The low natural density and the low growth rate of H. serratifolius (Ipê Amarelo), as well as H. impetiginosus (Ipê Rosa), typical of most of the other species within the three CITES-listed genera (Handroanthus, Roseodendron and Tabebuia), combined with high demand for international trade, habitat loss and degradation, has resulted in populations being negatively impacted. In the forests of northeastern Brazil, H. impetiginosus and H. serratifolius have shown drastic population declines, with no evidence of long-term population recovery. H. serratifolius is categorised as globally Endangered in the IUCN Red List of Threatened Species on the basis that it is threatened by international trade and is predicted to experience a population decline of at least 50% over the next 100 years (7). H. impetiginosus is assessed as Near Threatened, noting that its populations have declined considerably as a result of unsustainable exploitation for the international timber trade, with population declines of at least 25% expected over the next 100 year (7,8).
Unsustainable logging of the trees has led to significant declines in the population of the trees. The species also has a difficult time recovering from logging. In addition, the IUCN/Traffic have found evidence of illegal harvest and trade of the species as well as potential fraud in logging permits in Brazil (9). They also found that logging companies overestimated the sustainability of harvesting practices (10).
Conservation status of pau d’arco
Since 1997, H. impetiginosa has been considered Endangered, while H. Incana and H. serratifolia are considered Vulnerable. In 2015, a Working Group in which PEBANI participated, proposed a new Official List of Categorization of Threatened Species. In 2016, through Ministerial Resolution, this list was put up for consideration. All species of the genus Handroanthus maintained their categorization as Endangered or Vulnerable (11). The species has since elevated to international protection and monitoring of export trade as per the Convention on International Trade in Endangered Species (CITES).
The three genera Handroanthus, Roseodendron and Tabebuia were added to in CITES Appendix II at the Nineteenth meeting of the Conference for CITES of the Parties Panama City, November 2022. Entry into effect however was delayed by 24 months, i.e. until 25 November 2024. CITES Appendix II “lists species that are not necessarily now threatened with extinction but that may become so unless trade is closely controlled.” It also includes so-called “look-alike species”, i.e. species whose specimens in trade look like those of species listed for conservation reasons (see Article II, paragraph 2 of the Convention)(12). International trade in specimens of Appendix-II species may be authorized by the granting of an export permit or re-export certificate. No import permit is necessary for these species under CITES (although a permit is needed in some countries that have taken stricter measures than CITES requires). Permits or certificates should only be granted if the relevant authorities are satisfied that certain conditions are met, above all that trade will not be detrimental to the survival of the species in the wild. (See Article IV of the Convention)” The CITES listings came with Annotation #17 which limits the scope to logs, sawn wood, veneer sheets, plywood and transformed wood. This means that the inner bark used in traditional herbal medicine is excluded from CITES controls (13).
However, the inner bark is obtained as a by-product from felling entire trees for the logs, which still links this medicinal plant part to the overall controls and monitoring. Because the entire Handroanthus genus is listed in CITES Appendix II, it is supposed to go through a series of controls when transporting to the city. Because of potential fraud in logging permits, this is not a reliable method of ensuring that the trees have been harvested according to CITES guidelines.
CITES and the Peruvian Service of National Forest and Fauna (SERFOR) do not consider pau d’arco inner bark as commercially restricted. SERFOR requires a forest management plan for this product, which must be approved by them, along with field and warehouse inspections (11).
Sourcing of pau d’arco
Historically, the pau d’arco of commerce originated from the inner bark of H. impetiginosus trees native to Central and South America primarily obtained as a by-product of the logging industry in Brazil.
Though export trade of logs and wood from the trees are regulated by CITES, because of concerns over permitting fraud, buyers must ensure that they are purchasing from companies that know the source and are abiding by CITES regulations, such as a forest management plan and controlled harvesting. Other concerns are that the outer bark is mixed with the inner bark, which is the part of the plant that has the necessary constituents.
Companies typically purchase pau d’arco through a broker and so it can be difficult to get much information about harvesting practices.
I was able to get some information through a US based company who contacted their supplier who in turn answered my questions via email. They explained that they work with a network of trusted suppliers across Brazil, primarily in the regions in North and Northeast Brazil. They explained that the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA), the environmental agency overseeing the harvesting process, plays a crucial role in preserving both the local forests and communities. Through sustainable harvesting practices monitored by IBAMA, this supplier wrote, communities can continue to earn income and sustain their way of life.
Responsible sourcing
In the initial report that recommended inclusion of all Handroanthus species in CITES Appendix II, the authors didn’t find evidence that the trade for herbal remedies impacts wild populations. Logging and habitat conversion remain the main drivers. But ethical sourcing of pau d’arco can create a market for sustainably logging the ipê trees by ensuring that they are harvested only when a forest management plan is intact that accounts for harvesting levels and replanting practices. The company must also demonstrate that sourcing the material adheres to the guidelines in their forest management plan.
US based companies with whom I spoke who currently source their products from Brazil expressed their concern over the lack of visibility into the market for pau d’arco and an interest in finding traceable supplies.
Pebani, a Peruvian company, is currently working toward FairWild certification for yellow pau d’arco and offers an alternative source for this product (14). Pebani was started in 1996 to improve the livelihoods of rural communities in the Peruvian Amazon and Andes through the sustainable sourcing of medicinal plants. Cesar Barriga, the founder, a forest engineer, believes that the best-preserved forests are in the hands of indigenous people. Pebani is working to show indigenous communities that there is a market for products that are sustainably harvested and to provide these communities with the tools needed to source them.
As in Brazil, the main threats that facing pau d’arco in Peru are illegal logging, illegal mining, and subsistence farming. There is growing migration from the Andes to the Amazon because it is easier to work with crops in the Amazon. According to Paulo Barriga, Cesar’s son and Chief of Operations at Pebani, 90% of the deforestation in Peru is from burning to clear the forest for small farms, from 5–30 hectares. There is a value in providing ways of making a living through harvesting medicinal plants that require the forest to remain intact.
Pebani finds supplies of pau d’arco first by identifying local communities that are both well established and that have legal tenure to the area. This is difficult in Peru because many communities don’t have ownership rights to the area where they live. And so, as a second step, Pebani works with the community to help them get the ownership titles needed.
They then do a preliminary survey of the forest to see how many pau d’arco trees are in the region. They extrapolate from this number to the whole area. That then determines whether Pebani believe it is worth the investment of doing an in-depth forest management plan which will determine how much they can harvest from a particular area. The forest management plan involves walking the entire area and putting a tag and GPS marker on every tree.
Pebani presents this plan to the government to get the permits needed to begin working in the area. They also need to submit annual operating plans documenting their harvest. There is quite a bit of bureaucracy to get permits and other requirements from the government. This is very important, Paulo explained, because it helps the government control the process.
Harvest
Once Pebani receives an order, they identify those in the community who are willing to do the work. It’s difficult to find people because the work is hard. Once the trees are cut, the harvesters cut out the outer bark to harvest the inner bark. It is dried in solar driers in the field and then sent to Lima for further processing. Rather than selling the timber in the market, the harvesters are able to keep the wood to use for local construction. As part of the management plan, Pebani replants three plants for every one cut.
Pebani pays the harvesters by the kilo for the dried product. They work with collectors as long as there is an order.
Much of Pebani’s work is in the community with training. Because the trees take 20 years to grow, Pebani is also working in the communities to help them grow other crops like cacao, that can be grown in an agroforestry setting. Pebani staff are working with community members to develop different drying processes to bring more value to the community. Pebani invests in the communities in other ways as well, by providing water filters because the water quality is poor and a boat so that villagers can travel more easily.
Challenges
Some of the main challenges Pebani faces are the lack of ownership titles, the bureaucracy, and potential adulteration.
Another ongoing challenge for Pebani is the lack of demand. This means that they cannot provide a steady income to the harvesters, who then turn to other work, like clearing the forest for farming and livestock. Pebani pays a good price yet, Paulo explained, if they can only sell 100 kilos a year, they are still not able to provide a sustainable livelihood for the collectors. And so, paying fair prices is only part of the picture. There also needs to be a steady demand.
From Pebani’s perspective, it is good for companies to buy CITES products. Paulo said, “Some people believe that if something is listed in CITES they shouldn’t touch it. But even if you don’t touch it, people will still illegally harvest it. And wild harvesters who might sustainably harvest the tree will simply shift to another source of income like growing corn. It also means that when bigger companies are willing to source the species sustainably under CITES, they will be required to implement a plan to replant the trees and invest in the overall preservation of the area.”
To prove his point, Paulo mentioned an article by someone who bought a huge area of land in the Amazon, yet this person said that buying land wasn’t the best way to protect it because he didn’t necessarily know what was happening on that land. But if you are sourcing something sustainably from the area, you have to go there, you have to know what is happening on the ground. You need to work with the local communities and the government to make sure following the regulations.
FairWild certification
In 2022 Pebani began the process of becoming FairWild certified. They decided on the FairWild certification after speaking with Josef Brinckmann from Traditional Medicinals. So far, in working toward the certification, a risk analysis for pau d’arco and three other medicinal plants from the region were carried out, hired trainers to help them prepare the necessary documents and are provide training for the collectors. As soon as they complete the trainings for the communities, they will schedule the FairWild audit and begin being able to provide FairWild certified products (15,16).
I once asked Paulo what would a partnership based in mutuality and trust emphasize with a brand? He explained that Pebani is looking for collaboration with both brands and buyers. They hope to find buyers who are open to sharing the process around what they do around quality control, etc. to help Pebani better understand how they can add value to their process. In other words, Pebani is looking for buyers who work with them the way that Pebani is working in the communities from whom they source.
References
- Bussmann R. Assessment of equivalence of Tabebuia serratifolia (Vahl) Nichols and Tabebuia impetiginosa (Mart. Ex DC.) Standl. William Brown Center, Missouri Botanic Garden; 2012.
- Gentry A. A synopsis of Bignoniaceae ethnobotany and economic botany. Annals of the Missouri Botanical Garden. 1992;79(1):53-64.
- Rodrigues E. Plants and animals utilized as medicines in the Jaú National Park (JNP), Brazilian Amazon. Phytotherapy Research. 2006;20:378-391.
- Jiménez-González FJ, Veloza LA, Sepúlveda-Arias JC. Anti-infectious activity in plants of the genus Tabebuia.
- IUCN/TRAFFIC. Inclusion of trumpet trees Handroanthus spp., Tabebuia spp., and Roseodendron spp. in Appendix II with annotation #6. IUCN/TRAFFIC Analyses of Proposals to CoP18. 2019.
- Barriga P. Personal communication. March 18, 2024.
- Hills R. Handroanthus serratifolius. The IUCN Red List of Threatened Species. 2021. https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T61985509A145677076.en.
- Hills R. Handroanthus impetiginosus. The IUCN Red List of Threatened Species. 2021. https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T144297143A173394208.en
- Brancalion PHS, de Almeida DRA, Vidal E, Molin PG, Sontag VE, Souza SEXF, Schulze MD. Fake legal logging in the Brazilian Amazon. Science Advances. 2018;4(8).
- IUCN/TRAFFIC. Inclusion of trumpet trees Handroanthus spp., Tabebuia spp., and Roseodendron spp. in Appendix II with annotation #6. IUCN/TRAFFIC Analyses of Proposals to CoP18. 2019.
- Barriga C, Barriga P. Email communication. April 12, 2024.
- CITES. Appendices. [Accessed May 3, 2024]. Available from: https://cites.org/eng/app/appendices.php
- CITES. Index. [Accessed May 3, 2024]. Available from: https://cites.org/eng/app/index.php
- Pebani website. [Accessed May 3, 2024]. Available from: https://www.pebani.com.pe/
- FairWild website. [Accessed May 3, 2024]. Available from: https://www.fairwild.org/
- Schippmann U. Risk classification of species proposed for FairWild certification. Summary Data Sheet: Pebani, RA20200208 by IUCN Medicinal Plants Specialist Group. March 18, 2022.