Palo Santo Q&A with Researcher Elizabeth (Betsy) Collins

Elizabeth (Betsy) Collins is a Ph.D candidate conducting a research project on the sacred Palo Santo tree. We recently had the opportunity to connect with her for a Q&A while she was out in the field. The result is a fascinating look at the her story, research, and specialized take on the state of the Palo Santo industry. Check it out below!
betsy collins talking about her palo santo research project
Watch Betsy's video describing her research project

Q: Tell us a little about yourself! Where do you go to school and what made you decide to go there?

Collins: I am a PhD student in the Environmental Science and Policy department at George Mason University in Fairfax, Virginia (near Washington, DC). It has been a dream of mine to go back to school and get a PhD in plant systematics since I finished my masters in 2007, but I couldn’t find a professor that I wanted to work with where I was living (in Pittsburgh, PA, at the time). Then in 2014 I was reading the Botanical Society of America’s newsletter and saw my advisor, Andrea Weeks, mentioned. One of her students had won a research grant, and I noticed that she was at George Mason University, just a short commute away from where I lived in Washington, DC! I met with her and her students and knew that she would be a fantastic mentor (I was right!). Choosing the right advisor is crucial to having a good experience and successfully completing your PhD.

Q: How did you first hear about Palo Santo, AKA bursera graveolens?

Collins: I first heard about palo santo (Bursera graveolens) through my advisor, Andrea Weeks. She studies the systematics and evolution of the Burseraceae family, the plant family that palo santo is in, along with other aromatic plants like frankincense (Boswellia sacra) and myrrh (Commiphora sp.). She published a paper in 2009 in which they named and described a distinct subspecies of palo santo in the Galapagos Islands, and she mentioned that she still had the samples from her study. She said she thought there were some really great research questions and that I should dig around and see what I could find.

As I dug into the literature and learned more about palo santo it was like the research ideas just wouldn’t stop tumbling out of my mind! I wanted to know more, and everything I read led me to more questions and research ideas. At first, I had no idea that people used palo santo for medicinal and spiritual reasons – I just thought it made a great plant to answer some questions about the evolution of the seasonally dry tropical forest biome. I love the human dimension to the story of palo santo.

Q: What brought you to start your research project, and what do you hope to accomplish?

Collins: After a couple of years reading the literature and writing a research proposal (2017-2018), I was finally released into the wild to conduct my research after I advanced to candidacy in June 2018. But REALLY what brought me to start my research project is what brings all scientists to start … getting funding! I received a grant from the National Geographic Society for 2019 to cover my field research in Peru, Mexico, and Colombia, a grant from the Explorer’s Club to cover my field research in Ecuador, and a grant from the American Society of Plant Taxonomists to get me started on the molecular component of my research. I will be forever grateful to these funding agencies for making my research possible. I haven’t actually counted it up, but I think I have submitted more than 20 grant proposals to obtain funding for my research! You have to be willing to just keep going in the face of a lot of what can seem like rejection.

With my research I hope answer two big questions: 1) how many distinct species of palo santo are there and 2) how much genetic diversity do populations of palo santo contain? Quantifying genetic diversity in distinct populations of palo santo will allow me to develop recommendations for ongoing reforestation efforts so that they capture natural levels of genetic diversity in reforested populations. I will use a technique called ddRAD-Seq to sequence the DNA from 192 palo santo trees across its range to answer these questions.

palo santo tree in the wild
Palo santo tree (photo by Betsy)

Q: Could you please briefly walk us through your process? Is it difficult to locate the trees and extract samples?

Collins: Oh, I love this question! My process starts all the way back in something called an herbarium, long before I ever go to the field. An herbarium is kind of like a plant library filled with dried plant specimens mounted on large sheets of thick paper (no living plants!) with labels that tell you who collected them, where they were collected, and when they were collected. If properly stored, the specimens will last forever. Botanists have been collecting herbarium specimens for hundreds of years and storing them in herbaria. Herbaria are typically housed in museums (like the Smithsonian Natural History Museum here in DC that has over 5 million plant specimens), botanical gardens (like the Missouri Botanical Garden with over 6.5 million), and universities (George Mason has a small herbarium of about 65,000 specimens).

The very first part of any plant-related research project is figuring out where previous botanists collected your species of interest, and herbarium specimens have labels that ideally will tell you exactly where the specimen was collected, so they are the perfect starting point. I spent many months developing a database of specimens and inputting all the label data to create a map of where every specimen of Bursera graveolens had been collected. I reviewed specimens at the Smithsonian, New York Botanical Garden, loans I received from Missouri and the Herbario Nacional in Mexico City, and any other specimens I could find online. I also scoured the ecological literature for mentions of Bursera graveolens and then used the coordinates they provided as a point on my map. References in the ecological literature aren’t ideal, because they often are not accompanied by a specimen. So, a particular plant could have been misidentified, and you would not be able to independently check without going to the site.

After going through all the herbarium specimens and papers I could find, I ended up with a dataset of geolocated points (some much more accurate than others!) that I used to narrow down which regions to travel to in each country. I also reached out to other botanists that work in those areas to ask about how common the species was and if they knew where to collect it. Ultimately, I loaded the coordinates for the geolocated specimens in my GPS and used them as a starting point for looking for the species when I was in the field.

dry forest deforestation in veracruz mexico
Deforestation of dry forests in Veracruz (photo by Betsy)

My experience with how difficult it was to actually find Bursera graveolens once I got to the field varied widely, often for different reasons. In Veracruz, Mexico, there is almost no seasonally dry tropical forest left, so it was difficult to find palo santo, because its habitat is nearly all gone. But once we found a patch of dry forest in Veracruz (a huge thank you to Aurelio Molina, owner of the Reserva Natural Xocotitla in Veracruz), it became clear that palo santo is a dominant tree species in Veracruz dry forest, and we had no trouble finding many individuals. In the dry forest of Tumbes, Peru, and in Cerros de Amotape National Park in particular, palo santo is incredibly common, and I had no difficulty whatsoever finding individuals from which to collect samples. But, when I traveled a couple of hours south of Tumbes to the Piura region in Peru, my colleague, Paolo Villegas, and I drove around for hours looking for palo santo before we found a few trees. My collaborator, Miguel Puescas, at the Universidad de Tumbes, explained that in some areas of Piura, Peru, palo santo is cut down (illegally) to make fruit packing boxes for all the mangoes grown in the area. So even though there is still some dry forest left in the Piura region of Peru (although not a huge percentage), heavy local use of palo santo has led to its near-absence from this area.

dry forests in tehuacan mexico
Dry forest in Tehuacan Valley, Mexico (photo by Betsy)

The hardest part of obtaining samples is obtaining scientific collection permits and getting all the material exported to the United States (export alone can take several months)! I would never have been able to collect palo santo in Peru without my collaborators Dr. Miguel Puescas Chully at the Universidad de Tumbes, and Paolo Villegas, an independent botanist in Piura, Peru, who obtained permits for me. In Mexico, Dr. Mark Olson and Bruno Barrales at the Universidad Nacional Autónoma de México, made it possible for me to get permits to collect palo santo in Mexico. The Botanical Research Institute of Texas, and Dr. Alejandra Vasco in particular, made it possible for me to get permits to do field work in Colombia.

Compared to getting permits and locating areas where your species grows, collecting the plant is relatively easy! We spend a lot of our days in the field cruising slowly on the road and scanning the hillsides for palo santo. At the beginning of my first field collection trip to Peru, it was really tough for me to spot palo santo from a distance. Now, after three collection trips, I can spot it driving 50 mph! Once we locate a tree or trees from the road that we think we can access relatively easily, we pull over and grab all of our gear and hike to the tree. All I need to collect my samples in the field are some clippers to clip some branches to make herbarium specimens (long-pole clippers help for tall trees). Then once we get back to the hotel I press and dry the specimens (in Colombia I used alcohol preservation to simplify things), and I put some leaves in a bag with silica to desiccate them. This allows me to preserve the DNA in the leaves so I can extract it in my lab at George Mason. The hardest part for me is that I have to leave all of my collections and DNA samples in the country while we wait for export permits. It took about 3 months to receive my specimens from Peru!

picking ripe fruit from a palo santo tree
Ripe fruit from bursera graveolens (photo by Betsy)

Q: What is responsible for the beautiful crystal deposits so frequently found in the wood?

Collins: I would guess that the aromatic oleoresin (the thing that makes the wood smell so yummy) has the ability to crystallize and creates those deposits. If you cut into the bark of a live tree the oleoresin will actually drip out of the cut!

Q: How do locals feel about palo santo's rise in popularity? What is your degree of interaction with them when conducting research?

Collins: I interacted with local people very frequently when conducting my research. I find the knowledge that many local people have of their forests really impressive and, frankly, invaluable to me being able to actually find what I’m looking for. I now appreciate how important it is to know ALL the common names of your target plants. In the Caribbean coast of Colombia, for example, they don’t use the common name palo santo at all! In the Barranquilla area they call the tree “caraña”, but just a couple hours east along the coast in Santa Marta, they call it “bija,” and had no idea what we were talking about when we asked if they knew where “caraña” trees were.

I always had a botanist/academic-type colleague with me in the field that was from the country I was collecting in, but we always sought help from non-academic local rural villagers in the areas we collected in (and always, always paid our local help for their time). This is important for finding your target plant, but also extremely important for safety reasons, particularly in Mexico and Colombia. In Mexico we would always introduce ourselves formally to the local municipal office and then ask if they had a few people that would be willing to go out with us to help (and to make sure we didn’t unknowingly go into any unsafe areas).

My impression is that locals in Mexico and Colombia mostly have no idea that palo santo is popular on the international market. Mexico has nearly 90 named Bursera species (!) and Bursera graveolens is not a widely used species there. They mostly seemed to consider it unimportant or insignificant compared to some of the other Bursera species. Locals in Colombia know about palo santo because it is burned in Catholic churches, but I don’t think they know that it is also used in the United States. In Peru it seemed to be more well-known that the plant is used in the United States, especially by people working in sustainable development. Palo santo is kind of the perfect plant for sustainable development – products can be made from it without ever cutting down the tree! In Peru, my impression is that people are happy about the rise in popularity, because it has the potential to help conservation and improve the livelihoods of the people there.

man standing by a palo santo tree
Paolo Villegas with a palo santo tree (photo by Elizabeth Collins)

Q: Do you find that the regulations which have been implemented by governments to protect and preserve the species are sufficient? If not, what measures would you like to see implemented that would raise that bar?

Collins: From what I understand, of the countries that palo santo is native to, only Ecuador and Peru specifically protect palo santo by making it illegal to cut it down. I haven’t yet collected in Ecuador so I can’t comment about the effectiveness of their protections (I will be there in February, though!). But from how difficult it was to find palo santo in parts of the Piura region I would say that the regulations in Peru are not effective in places where there is a very strong economic incentive to cut down the trees. Also, regulations are really only effective if they are enforced, and I don’t know how much enforcement they have the capacity to do in Peru. Personally, I would prefer an approach that focuses on giving local communities an economic incentive to conserve their forests rather than trying to create more regulations or boost enforcement. Telling people not to cut trees just doesn’t work when they have no other sources of income.

Effective conservation requires a strategic approach to addressing the unique pressures palo santo faces in each area of its range. Generally, though, palo santo populations are facing two main sources of pressure: massive habitat loss of its seasonally dry forest habitat and illegal extraction of individual trees from the remaining forest. Habitat loss is a difficult problem to solve, because people need places to live and land to grow crops, but I think it starts with educating people about the unique and wonderful place that is the seasonally dry tropical forest. Only about 10% of the original extent of the Latin American seasonally dry tropical forest remains intact in many areas, little of which is protected. We need to allocate more money to dry forest conservation, with a particular focus on the remaining intact dry forest areas. I hope some of my pictures and blog posts can show people the beauty of the dry forest and spur more interest in dry forest conservation!

dry forest in cuaca river valley, colombia
Dry forest in Cuaca River Valley, Colombia (photo by Betsy)

Selective extraction for local use of palo santo contributes hugely to the declines of palo santo populations. From what I saw during my fieldwork, it appears that pressure from selective extraction for local use is much heavier in some regions than in others, and can be for very localized reasons. Palo santo is used medicinally to treat the common cold and arthritis, among other things; burned as incense in Catholic churches and in people’s homes; and burned as mosquito repellant. Across much of its range, people cut down live palo santo trees and sell the wood in local markets for these uses. However, in the Piura region of Peru, palo santo is also used to make fruit packing boxes, particularly for mangoes. Miguel Puescas Chully, my collaborator at the Universidad de Tumbes, estimates that 10 trees per hectare per year are cut to make these boxes! There are illegal sawmills that buy the cut palo santo trees from local people. These sawmills then make the fruit packing boxes and sell them to agricultural companies in the area. In the Piura region of Peru, we had to drive for hours some days just to find a few palo santo trees due to the heavy local use for fruit packing boxes. The people living in these regions in Peru are living in extreme poverty, so I don’t fault them for doing what they need to do to support themselves. Any successful conservation strategy cannot ignore the needs of local people surrounding the dry forest.

The biggest unknown to me is the degree to which international use of palo santo is contributing to population declines, but I hope to work on answering this question after I finish my dissertation. I wrote a blog post that addresses this question a little bit, though, with all the information I have to date. In short, the sustainable use of palo santo, where only dead, fallen wood is used, does not hurt populations. In fact, this use helps populations, because it gives local communities an economic incentive to conserve palo santo so there is always a source of dead, fallen wood. I don’t know how much of the palo santo on the international market is from sources that have cut down live trees, though, but I hope to find this out in the coming years.

naturally fallen palo santo tree marked for harvest
Dead, fallen tree marked for later harvest (photo by Paolo Villegas)

One strategy that I think we could use to solve both habitat loss and selective extraction is large-scale reforestation of the dry forest, with palo santo being one of the key planted species in certain areas (especially Ecuador and Peru). Bioversity International has compiled a really useful database of all the restoration projects in the dry forest in Peru and which species are being used. Palo santo is being used in 17 of these projects! For these reforestation projects to succeed, though, we can’t just plant lots of trees and tell people not to cut them. First, we need to make sure that we are planting populations of trees in restored forests that contain enough genetic diversity to adapt to future diseases and our changing climate. This is one of my big goals of my PhD research: to determine the genetic diversity of palo santo populations so that we can develop seed collection plans that take genetic diversity into account. We need to ensure that the planting material used in reforestation projects is genetically diverse and matches the genetic signatures of local populations, or these reforestation projects are at risk of failing to meet the conservation goal of restoring the dry forest.

I would also like to see these reforestation projects include the local community as a major stakeholder in developing sustainable use plans for restored forests, which could include some selective extraction in certain areas of the forest to make fruit packing boxes and other local uses. If we ignore the needs of local people in communities surrounding these forests, the forests will be under constant threat. We should also focus on developing sustainable sources of income for local communities from international sources, and I think palo santo is the perfect plant for this. You can make a variety of products from palo santo without ever cutting down a single tree! You can extract essential oil from the fruit and use the dead, fallen wood to make jewelry and incense sticks. This is why it is so important to choose your source of palo santo very carefully, and make sure you are supporting local communities that are contributing to dry forest conservation. I visited an unbelievable community in the town of Mangamanguilla in the Piura region of Peru that has conserved 1700 hectares of dry forest. I can totally imagine an ecolodge that caters to birders and rafters and the more adventure-seeking tourist in Mangamanguilla!

Read: Q&A w/ Third Eye Wood's Peruvian Partners

Q: Based on your research and experience in the field, what is the best trajectory for the sustainable future of Bursera graveolens?

Collins: Reforestation of natural habitats combined with sustainable use of palo santo, where only the dead, fallen wood OR planted trees are used for products. A sustainable future is completely possible!​

Q: How does climate affect the density of the wood and the concentration of terpenes which vary from tree to tree?

Collins:I don’t know the answer, but this is such a good question! This would be such an awesome master’s project! Any students out there interested in studying this??? Let us know in the comments!

Q: How can readers contribute to your research project?

Collins: Please visit my project to contribute or just to learn a little more about palo santo. The fundraising campaign ends December 4th.

Q: Any other interesting stories from your travels you'd like to share?

Collins: I have soooooo many stories I could tell you! I wrote about my experience in the village of Mangamanguilla already (check it out here). Visiting Mangamanguilla is in my top-five field memories for sure! I have a less-than fun story to share, though, since I don’t want to make it seem like field work is all fun. When I was in Colombia working at the Universidad de Antioquia, a leftist guerilla organization called the ELN (National Liberation Army in English) attacked the University. They set off dozens of small bombs, and we ultimately had to evacuate the university. It was pretty terrifying, although my colleagues assured me it was normal, which didn’t assure me at all.

Q: What's next on your journey?

Collins:I will finish my dissertation and graduate in 2021 (fingers crossed!). After that I would love to continue my work with palo santo and dry forest conservation. Two big projects I want to work on are: 1) working with agricultural companies in the Piura region to decrease the demand for fruit packing boxes made from illegally cut palo santo trees; and 2) answering the question “how much does the international market contribute to population declines of palo santo?” If I find that the international market does in fact contribute to population declines in any meaningful way I hope to create an independent certification program that would certify palo santo products as sustainable. Kind of like the program for bird-friendly coffee if you’re familiar with that.

elizabeth collins holding a bird while in colombia
Holding a macaw in Reserva Palomar near Barranquilla, Colombia (photo by Lewis)


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