An update from Christopher, a Ph.D. candidate in anthropology:
In June I attended the 8th International Workshop for African Archaeobotany (IWAA). In the last post I introduced the scope of the four-day workshop and described the diverse uses of plants in early societies.
Much of the conference work presented also demonstrated the potential for methodological developments to shed light on past problems. For example, in addition to flowers, seeds, and fruit, plants also produce durable and diagnostic microscopic bodies such as pollen, starches, and phytoliths. These can provide extremely detailed reconstructions of past environments and human activities.
Microbotany, the newest development in this group of methods, is the identification of plant phytoliths, which are small silica bodies produced inside of and between the cells of plants. Some plants, like grasses, use the silica bodies as a defense mechanism against herbivores, but most terrestrial plants produce them. Since these bodies are made of silica, they preserve quite nicely in conditions where other organic remains do not, which makes for a particularly exciting aspect of phytolith research.
Some presentations illustrated how phytolith evidence produced details that were not available in the macroscopic record. Research from South Africa attempted to link phytoliths with subsistence choices among hunter-gatherers, while studies from Sudan provided direct comparisons of macrobotanical and microbotanical evidence.
The most pressing issue facing phytolith research is empirical. One presentation in particular stood out: by processing, identifying, and comparing the phytoliths recovered from the bark and interior of woody plants, the presenter provided an important critical context for phytolith studies. The clearer our understanding of how phytolith morphology is associated with different plants and plant parts, the better our ability to reconstruct past behaviors and climates.
The study of fungal spores is another avenue of microbotanical research that is beginning to take shape. An onerous task, as the diversity of soil microbes and fungi is truly daunting, but also a worthy task, because these microbes and fungi thrive in soil microclimates that are especially sensitive to human modification. While other methods rely on the appearance of known domesticates, these approaches are promising because they can, potentially, detect the appearance of human behaviors that led to agricultural production such as selective burning or storage.
Studies of plant pollen, known as palynology, also provided important insights at this meeting. By reconstructing the plants present in sedimentary and cultural contexts, these presentations shed light on the deep ecological understanding of African populations past and present, and their intimate links with climatic change and historic developments. Recent research from Nigeria illustrated this point nicely by identifying both climatic and behavioral developments in a hunter-gatherer site, providing clues that suggested prehistoric populations made the most of changing environments for resources beyond subsistence. Medicinal and cultural qualities continue to play important roles in the way that human populations utilize plants.
My own research fits into this category. My goal was to address a long-standing debate about the origins of modern vegetation in Africa. Scholars debate whether humans or climatic change played a primary role, but the field has developed significantly in the last two decades. Researchers have come to understand that a single cause is unlikely. Instead, we have come to focus on examining how cultural changes articulate with changes in climate. This research requires testing records that are sensitive to human activities, and I chose to sample sediments associated with tropical rivers.
Archaeological surveys in my study region, the Ngotto Forest of the Central African Republic, have validated oral histories from the region and indicate that this patch of tropical rain forest has been inhabited since at least 1,700 years ago. The results of my research show a dramatic shift in forest cover during the centuries leading up to and after European colonization.
Because these records yielded a detailed environmental history of my study area, I was able to demonstrate that, rather than being ahistorical, the tropical forests of central Africa were home to a vibrant iron-smelting industry that lasted until the brutal suppression of the region at the hands of imperial France. This period is also documented by the records I sampled in the Ngotto Forest, and it shows a sudden shift towards reforestation after communities of iron-smelters and farmers were forced to work on colonial lumber concessions or plantations.
Archaeobotanical studies provide important lines of evidence that help us better understand the human past and present. The rewards for human understanding are more than proportional. As human kind looks towards an increasingly uncertain future of food production, resource management, and climate change, this body of research becomes more important because it is the only means of understanding long-term interactions between humans, vegetation and climate. These studies are germane to the problems that we face today and provide the only laboratory for understanding how our species copes with our current issues. This also provides us with hope. Humans, like any other animal, have developed intimate relationships with plants that have shaped us both. With deeper understanding of the resources we depend on, we come closer to successfully managing our future.