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Forensic investigators are faced daily with huge caseloads and an extremely small window of time to accurately interpret evidence. As each day passes without conclusions from forensic experts on their aspect of the case, the chances of determining scientific and crucial conclusions about the crime are drastically reduced. For this reason, it is imperative to each investigation that investigators have specialized in a specific field of study. By having a team of such highly trained, focused individuals, investigations can be executed as quickly as possible because each person thoroughly understands the subject that he is responsible for. Another factor that can increase the investigation's results is having a number of different forensic specialists on each investigatory team. A group of experts can then produce more answers to the questions that the team has been assigned to. They will be able to determine more based on the various types of evidence, which can then add to the investigators' chances of accomplishing its goals in identifying the victim, the assailant, or, perhaps the circumstances surrounding the particular crime.
There are infinitely many disciplines to which a forensic investigator can devote his time and interest. Traditional fields of study include examination of physical evidence such as firearms, fingerprints and basic psychology. Now, however, with advances in technology, relatively new areas of interest to forensic experts are showing their usefulness to investigators. Such areas include DNA examinations and other chemical analyses, psychological profiling, and the oft-neglected forensic aspect of botany. Each of these sources of information can provide essential clues to investigators, and it is important to take advantage of every potential aid in a forensic investigation.
Forensic botany is the study of plants, and plant matter, as they pertain to criminal death investigations. Forensic botany can provide clues as to when a person died by giving investigators a time frame in which approximations of time of death can adhere to. Having an estimation of estimated time elapsed since death can allow investigators to include and exclude suspects, determine whether or not the case is of current forensic interest and give information on how the person died. Palynology, a sub-discipline of botany, can also provide information about whether a body has been moved since death and where the body has been recently. This data can then be used to support or contradict witnesses and, possibly, accused's statements, or perhaps lead investigators to the actual scene of the crime, as opposed to the place where the body was found. While the use of forensic botany in investigations has proved to be extremely rewarding as far as offering more information about a particular set of circumstances, it also has certain limitations that must be respected. The study of plants as they relate to forensic issues is being relied upon more and more as it consistently demonstrates itself to be beneficial to death investigations.
One of the most practical uses of forensic botany is to learn how long a body has been laying in a particular spot (Kerley, 1978). Dendrochronology, the counting of the rings in a root, has been a popular choice for determining when a body was buried. If, for example, the ground around where the body was found has been shown to have been disrupted when the body was buried, it can be assumed that any new growth began approximately when the body was buried (Quatrehomme et al., 1997). By counting the number of rings in the new growth, a date, within a year, can be acquired (Vanezis et al., 1978). Along similar lines, if a plant that is in place when the body is buried is damaged, "it is, in fact, possible to count the number of annual rings that have been formed since the injury" (Quatrehomme et al., 1997) thereby giving investigators an estimated elapsed time since the burial. Finally, by studying the length and size of roots found in a burial site, an investigator can rely upon independent data that approximates average root growth for the same plant and apply it to the roots found at the grave (Quatrehomme et al., 1997). In essence, a pre-determined mathematical constant describing the rate of growth for a particular root would be entered, along with the length of the actual root, into a formula, resulting in the number of days, weeks or years that the root has been growing, which then relates the number of days, weeks or years that the body has been present at that particular site. The advantages of studying roots in a forensic sense can thus focus an investigation as to approximately when a body was first placed in a certain grave, saving investigators' time and allowing them to turn to other important tasks.
Forensic palynology, as described by Horrocks et al. (1998), "is the science of deriving evidence for court purposes from pollen and spores." Pollen is the male gametophyte released by plants, in order to fertilize and perpetuate the plant's species. Extremely light, and often airborne, pollen can be found nearly everywhere, often referred to as a "pollen rain," meaning that pollen is constantly falling from plants and moving by way of the wind. Because no one can shield himself from this pollen rain, people carry vast amounts of pollen on their clothing, in their hair and on their skin, without being aware of it. As well, as a result of differing pollen-producing vegetation in any two areas, the pollen found on a person in one area will be different than the pollen found on the same person in another area. This final point is of interest to forensic palynologists, as each person unknowingly and unavoidably carries pollen evidence on his person showing where he has been recently. If a body is found near a particularly rare pollen-producing plant, it is possible and likely that the killer has this same pollen on himself, or perhaps the clothes he was wearing at the time of the attack or burial. Because the type of pollen is rare, the pollen evidence could place a suspect at the scene of the crime. Again, as a result of the many different types of pollen falling at any particular time, areas have different combinations of pollen, which, when found on a suspect, produce further evidence that he has been at the scene of the crime. Through extensive research, Horrocks et al. were able to show that different areas which seem to contain similar vegetation to each other, in fact differ "significantly from those of other... areas of similar vegetation type" (Horrocks et al. 1998:322): a conclusion which further places a suspect at the exact scene of the crime. Assuming that the palynologist can prove that those particular pollen seeds from the scene of the crime or burial match, or are similar to pollen found on a suspect, the finding of differing pollen, in the same specific and unique combination, is extremely effective and condemning evidence against a suspect.
As with almost all tools used by forensic investigators, forensic botany does have limitations that must be considered when botany is used in a death investigation. An incorrect conclusion by a forensic team could have severe results as the experts change their focus to support the previous wrong outcome. In a death investigation, where the people's safety could be threatened by a criminal who has not been caught, one can appreciate that all results turned up in an investigation must be valid. The problem with palynology, is unfortunately, quite similar to its benefits. As pollen rain covers both the suspect and victim at the scene of the crime and burial site, it is also falling on important evidence. When a piece of evidence is extracted from the ground, extreme caution must be taken to cover it immediately, as pollen from the scene begins to contaminate it. The mroe pollen that falls upon this evidence, the more difficult it becomes for investigators to determine whether the pollen was there at the time of death, or when the evidence was recovered. With this one concern of the use of palynology, it seems to be a more certain way of learning about a particular crime as there are a number of different problems in associating time of burial to plant roots. Quatrehomme et al. were able to isolate several matters that make investigators' tasks even more difficult as they search for answers. While counting the number of rings in a plant to learn how long that plant has lived, and therefore, how long since the soil has been disturbed, false and incomplete rings do occur (Quatrehomme et al. 1997). An extra, false ring or a distorted ring can greatly affect an investigation, and because it is impossible to account for these anomolous rings, simply counting the rings of a root provides only a vague idea of the plant's age. Because plant matter on a body does not necessarily correspond to the length of time the body has been there, investigators must be aware that they may be looking at older or newer plant growth from when the body was buried (Quatrehomme et al. 1997). It is possible that an older, more fully developed plant will take over the younger vegetation. In this struggle of nature, the older plant may grow over the grave, confusing an investigator's analysis of the scene as he wrongfully presumes this developed plant to be the youngest plant. Similarly, if the body is covered at the time of burial, some of the original plants may be replaced over the body (Quatrehomme et al. 1997), again giving the investigator a false impression of the scene, as the plant he looks at has been at the scene longer than the body below. Oppositely, "decomposition must first reach a certain stage before roots can penetrate areas of skin loss on the cadaver" (Quatrehomme et al., 1997:142) which could cause a plant younger than the time of burial to be present at the surface, as its growth has been delayed by the body's rate of decomposition. These limitations of forensic botany are extremely important to investigators, but they do not contradict the aid that forensic botany offers to forensic teams.
At this stage, "forensic botany is a valuable tool that deserves wider use" (Bock et al. 1997). As each new study is completed outlining the advances that have come from botany and their relation to criminal investigations, it becomes apparent that forensic anthropology has much to gain from this field of study.
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