This post is based on a video from my YouTube channel.
Have you ever wondered what plants have to do with archaeology? In this post, you will find the YouTube video breaking down how and why plants are important for archaeological research and a full transcript of the video (with relevant references and links).
YouTube Video
YouTube Video Transcript
Here you will find the complete transcript of the video in the previous section. There are time stamps for every minute if you want to navigate to a certain part and hyperlinked references/citations.
[00:00:00]Introduction
When people think about archaeology, plants are usually the first thing that comes to mind. But there are archaeologists who are deeply interested in plants.
Why?
Because humans all across the world from all time periods have depended on them for food, shelter, medicine, and so many other reasons.
Most archaeologists have some type of technical specialty, and one of mine happens to be plants.
If you’re new here, hello, my name is Smiti and I’m an archaeologist. And today we’re gonna talk about what plants have to do with archaeology.
Definitions
So how do archaeologists actually study plants? Well, parts of plants actually get left behind after we use them.
Think about the last time you were at a cookout or a picnic, and maybe some of those corn kernels fell into the grill.
Lucky for archaeologists. That happened in the past too, and that’s where the paleoethnobotanists come in.
I know the word paleoethnobotanist probably sounds like a mouthful, so let’s break it down. “Paleo” refers to old, “ethno” refers to people or culture, and “botanist” describes a person who studies plants.
So together you get a [00:01:00] person studying plants as they relate to people in the past, and that essentially describes the meaning of a paleoethnobotanist.
So sometimes these specialists are called archaeobotanists, and the same idea goes here. So “archaeo” referencing archaeology and “botanist.”
Now these terms are pretty much the same, and they’re often used interchangeably and paleoethnobotany tends to be used more in the US, whereas archaeobotany tends to be used more everywhere else in the world.
Now, if you’re interested more in this, there’s a whole blog post in the description that goes into the history of these terms.
History
Archaeologists have been using plants to learn about the past for nearly 200 years. As early as the 1860s, scientists, like the Swiss naturalist Oswald Von Heer, used fossilized plant remains to learn more about ancient plant life.
Now the term paleoethnobotany that we just talked about was first coined by a Danish botanist named Hans Helbaek in 1959, and he sought to bring botany and archaeology together by studying wheat agriculture in ancient Egypt. Since the 1960s, the marriage of [00:02:00] botany and archaeology has been strong. In the 1970s and eighties, many paleoethnobotanical studies focused on questions like the origins of agriculture, crop domestication, and human adaptations to the environment. Since the 1990s, archaeologists began to study an array of topics like the role of women in growing food, how enslaved people in the American South defied their enslavers by foraging for wild plants, or how inequality shapes food insecurity in Ghana. The field became more popular through the 20th century, and scientific techniques improved to help us more accurately find and identify plants at archaeological sites.
So how do we do it?
Well, a lot of different plant parts actually preserve in the soil at archaeological sites.
So let’s walk through the five key plant remains that we find in the archaeological record and what they can tell us about the past.
Seeds
The first is seeds.
Seeds are what archaeologists call macrobotanical remains, which means you can see them and pick them up without a microscope. This is different from a microbotanical remain, which requires a microscope, and we’ll [00:03:00] talk about micro botanicals a bit later.
Seeds are really useful to archaeologists because they can often tell us what people were eating in the past. If you think about it, so many of the plants we eat have things like seeds, pits, kernels, so think about peaches, apples, corn, watermelon, cherries, and the list goes on.
Usually when seeds are found in the archaeological record, they’re near some type of cooking area, such as a hearth. Seeds best preserve when they’re exposed to heat in a process called carbonization. Now, there are other ways that seeds can preserve, like waterlogging or mineralization, and I’ll have references in a blog post below. But today we’re gonna focus on carbonized seeds.
When seeds are carbonized, they become slightly burned, but not so burned that they turned ash. Now they usually look black or a little grayish, and that’s due to the burning process.
This process preserves seeds and prevents them from decomposing in the dirt.
Some of the oldest known carbonized seeds come from Southern Egypt and have been radiocarbon dated to about 8,000 years ago.
Archaeological studies from around the [00:04:00] world have used seeds to figure out what kinds of plants people were eating or using for different purposes like animal feed or medicine.
For instance, archaeologists working at a Viking age farmstead site in Iceland found charred barley seeds in animal dung. Based on this, they concluded that the Icelandic farmers were growing barley and letting their sheep graze on the fields.
Analyzing seeds can be combined with other methods to learn even more about the past.
For example, last year, a team of archaeologists working in Libya found 6,000 year old seeds. They combined this with DNA analysis, and they were able to find out that the seeds belonged to a wild watermelon. This discovery enabled them to figure out what kinds of plants ancient foragers were able to find in the harsh Sahara climate.
Charcoal
Next up we have charcoal.
Like seeds, charcoal is considered a macrobotanical because you can see it with a naked eye. Charcoal is just burnt wood like you get after a bonfire, you can take a piece of charcoal and if it’s well preserved, you can see different anatomical features of wood. For example, when a tree grows, it creates rings that [00:05:00] represent each year of its life. And sometimes you can see these growth rings under the microscope. (Thanks to Lucas Proctor and the UConn Archaeobotany Laboratory for providing us an image of a transverse wood charcoal (Quercus sp.) section at the 4:52 and 5:03 mark of this video.)
Different types of trees have different identifying features so think of vehicles. Some have four wheels, some have two, and some have 18. And the wheels are just one indicator of what type of vehicle it could be.
Same goes for identifying charcoal.
We tend to use comparative samples or guides to help us figure out what trees were burned based on these features.
While seeds tell us about what people in the past were eating, charcoal can be useful for telling us what kinds of trees people used as fuel in their fires, or even what kind of wood they use to build their houses.
At a 5,000 year old site in modern-day Turkey, archaeologists were able to recover charcoal that was burned as part of a copper working workshop near a growing ancient city. The scientists found that nearby forest around the city were cut down in order to support the metal industry, which requires many large fires demanding a huge number of trees.
Pollen
Next up is Pollen.
When you think of pollen, you might think about hay fever or that yellow coating on your car. In spring.[00:06:00] Many different types of plants produce pollen in their flowers as part of their reproductive cycle.
Individual pollen grains are tiny. You need a microscope to be able to see it. So archaeologists call pollen a microbotanical.
Different plants produce pollen grains that look unique. So for example, a sunflower’s pollen is round with tiny spikes around it.
Archaeologists can separate ancient pollen grains from sediments found during archaeological excavation.
Now using modern comparisons, they hopefully can then identify the pollen grains to reveal what types of plants we’re growing at the site.
Pollen analysis has so many different types of applications, and it ranges from reconstructing ancient diet to figuring out what trees grew in ancient forests.
One interesting use of pollen analysis is in the case of the famous Ötzi, the iceman. Now, this is the 5,300 year old mummy that was found by hikers in the glaciers of the Alps in 1991. Ötzi is so well preserved that archaeologists have been able to figure out exactly what and when his last meal was. By using pollen and DNA analysis from his stomach [00:07:00] contents and belongings. Researchers have been able to figure out that he ate wheat bread and wild fruits shortly before his death. Also, based on the presence of the pollen of certain summer flowering trees, the scientists working on Ötzi were able to deduce that he died in early summer.
Some of the content of this section were adapted into a more detailed blog post written by team member, Anya Gruber: http://www.anyaegruber.com/blog/he-was-sunshine-i-was-pollen-rain
Phytoliths
The next plant remain is phytoliths.
The word phytolith comes from the Greek words, “plant” and “stone”, and that does a pretty good job of summarizing what a phytolith is. They’re basically tiny rocks inside plant cells.
When plants grow, they absorb water and nutrients through their roots. During this process, they also absorb dissolved minerals like silica, which is essentially the same material as rocks.
These minerals get deposited inside the plant cells and then they get left in the soil after the plant dies.
Like pollen, different plants produce phytoliths with different shapes and sizes so we can match the phytoliths we extract from archaeological excavations with certain plants that grew at the site, phytolith analysis is often used to learn about ancient diets, environments, agriculture, and plant domestication.
Often [00:08:00] archaeologists will use phytolith analysis in conjunction with other methods like DNA analysis or pollen analysis.
At an archaeological site in northeast China, a team of researchers used phytoliths to reconstruct ancient environments and better understand agricultural practices. Based on the discovery of millet, which is a grain similar to wheat and rye alongside other phytoliths. The archaeologists found that the environment in the area of the site was warm and wet about 6,500 to 5,600 years ago, which was an ideal environment for agriculture and led to a prosperous time in the area.
Some of the content of this section were adapted into a more detailed blog post written by team member, Anya Gruber: http://www.anyaegruber.com/blog/phytoliths-the-snowflakes-of-the-plant-world
Starch
Last up, we have starch residue analysis.
Starch is the type of sugar molecule that is produced in leaves as a byproduct of photosynthesis, and then is often stored by the plant as tubers, roots, and seeds. Some notable plants that contain a significant amount of starch include potato, cassava, wheat, and corn.
When humans process food, such as grinding something into flour and then storing it into a container, these starch grains are then deposited on these tools and [00:09:00] containers. Archaeologists can then examine the residue from starch grains on these surfaces to identify the plants that were being processed.
In some cases, starch greens can even be analyzed from residues on human teeth.
A team of archaeologists working in northern Peru looked at starch grains from teeth of people who lived between 7,000 to 8,000 years ago, they identified that they were eating beans, squash, and the fruit of a South American tree called an ice cream bean tree.
This study was significant because it shows some of the oldest and most direct evidence of people eating these culturally significant foods in the Andes.
Many of the case studies we mentioned today rely on archaeological field work. And if you’re curious what that looks like,
I have a whole video that takes you behind the scenes of my archaeological field work trip to Oman. Now, if you’d like even more information on what plants have to do with archaeology, we’ll have a blog post in the description that links today’s references and even more information.
So that’s all for today’s video, and we’ll see you in the next one. Bye
Credits
Anya Gruber: Co-Producer, Lead Video Editor, Researcher, Scriptwriter
Smiti Nathan: Director, Co-Producer, Support Video Editor
If you enjoyed this post, check out my channel and other videos.
