Plant science and its applications have been studied for thousands of years, first being explored by naturalist Ulisse Aldrovandi (1522-1605) who was considered the father of natural history with his research including the study of plants. In 1665 polymath Robert Hook discovered cells in cork, and later on in living plant tissue. However, what many people are surprised to hear is how plant science, known in the forensic setting as forensic botany, can be used to help solve modern-day crimes.
How does forensic botany compare to the other ecological disciplines?
Forensic botany is the application of plant sciences to criminal investigations. It involves looking at plants and trees to identify patterns in evidence that can be associated with a landscape, time of year or a person’s movement within a landscape.
In regards to other ecological disciplines such as diatoms and soils, it is a similar type of investigation. Ecologists try to assess how a person has moved in a landscape, what time of year they moved in a landscape and where they have been through the use of plants. This includes consideration of the type of landscape we are looking at to identify the types of plants that flourish and thrive in those particular environments. However, instead of looking at things on a macroscopic scale, we are looking at the pieces of evidence that we can see with the naked eye.
When and how is forensic botany used?
A good example would be looking at vehicle movement. If there is vegetation adhering to a vehicle we can assess the vegetation, identify it and think about where it has come from and what that could mean.
Let’s take a vehicle had seeded grass heads lodged within its wheel arch, for example. What it tells you is that vehicle has pulled up against the side of a bank, the grasses are roadside grasses and it also tells you a bit about the time of year. Seeds are a springtime occurrence and the seeds in question were still green and that indicates they were sown in springtime that same year. From this information alone we are already beginning to build a narrative or sequence of events.
What are the limitations of forensic botany?
The findings from forensic botany do not necessarily link someone to a murder investigation, however they can provide a story for where a person or their vehicle has been at a given time.
In the UK we don’t have particularly distinct different environments. If you are really fortunate you might get a rare plant or tree that a person has brushed up against to help place them in a specific environment/scene of a crime, however in the UK we deal with quite generic landscapes. We have the urban environment where everyone grows the same petunias and tulips in their gardens, we have woodlands that are quite generic, and we see the same wheat and barley that grows in agricultural fields.
In terms of plant distribution, actually pinpointing it to a specific location (as with all of the forensic ecological disciplines such as soils, diatoms and pollen) doesn’t provide you with the precise information that you need. However, it can be useful for providing a context for where someone has been.
How often is forensic botany applied to criminal investigations?
The key point about forensic botany, as with all of the areas of ecological investigation, is that they are all addressed at the same point.
If we receive a case where we have botany built into the exhibit we will comment on that. We don’t necessarily receive a call requesting a forensic botanist, it tends to be built in as part of the forensic ecology package. It is an integrated aspect rather than a standalone area.
When we attend a scene we will often undertake a botany survey. One of the common misconceptions is that we are in attendance with a microscope identifying all of the plant species in the area. Instead, we use forensic botany to give a broad overview of what the environment is.
What’s used to help identify the different plant species in a specific area?
Plant books. No-one knows every plant and every tree in the world, but it’s about going out on the scene, looking at what’s around you and distinguishing them through identification books.
How has forensic botany been used to help solve a case?
We have worked on a body deposition case where a recovered victim was found with leaf matter all over their cadaver. We identified the leaves as belonging to a yew tree. Yew trees are unique in that they stand alone, they grow as solitary trees and you tend to find them in graveyards.
They are very old and when they get to a certain age, as they live for thousands of years, they stop growing up and they hollow themselves out to reduce the amount of nutrients they need to survive. The yew tree placed the suspect in a specific woodland near to where he lived, so we knew that it was likely the victim was killed at a different site to where he was found.
Ultimately, identification demonstrated that the suspect had been somewhere else, and that allowed the police to widen their investigation.
How does forensic botany compare to the other ecological disciplines?
We use the soils, the vegetation and the ecology to build a big, broad ecology picture: what does this landscape look like? What potential indicators could be on a suspect’s vehicle that could pin them to that environment?
Forensic botany has been built into other forensic scientists’ work and at the moment it is probably more popular than diatom analysis.
Alecto Forensics is a UK leading forensic ecology service provider, delivering specialist forensic services and expertise to police forces across the UK.
We have over twenty years of forensic ecology experience within major crime investigation and pride ourselves on being an independent, quality-driven forensic service provider. We have a host of accredited experts and our expertise is available 24 hours 7 days per week.
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