To study the interrelationship between humans and plants through time, paleobotany (or paleoethnobotany), recovers and analyzes both macroscopic and microscopic botanical remains. In the Near East, macroscopic plant remains are preserved primarily through carbonization, or charring. Seeds, wood, or other plant parts that have been exposed to heat of sufficient intensity will turn to carbon while essentially retaining their original shape and size. These remains are often found during excavation in ceramic vessels, storage facilities, and hearths or scattered as debris on floor surfaces. Where remains are not dense and have not been collected by hand during excavation, a flotation, or water-sieving, device is used. In flotation, excavated soil is placed in a large container of water and carefully agitated. The carbonized material floats to the surface and can be scooped off, poured off, or directed through an overflow spout into a sieve or other container. When dry, the remains are sorted and identifiable plant remains are removed.
Microscopic plant remains include pollen or phytoliths, which are also important in understanding ancient environments and plant use. Wind disperses pollen from plants over wide areas. Some is deposited in lake beds, bogs, and other permanently wet, still waters, where it sinks to the bottom and is rapidly covered with sediment. There it becomes sealed in an anoxic (oxygen-free) environment, where it can be preserved for thousands of years. Cores of lake-bed sediments (i.e., sample columns of sediment extracted by forcing a tube vertically into the sediment) can yield a record of the pollen deposited, thereby allowing a reconstruction of the vegetation in the region and the changes in this vegetation through time. These changes can be linked to climatic fluctuations or such human action as deforestation, depending on the nature of the change and the types of plants involved. Phytoliths are microscopic silica bodies in plants that take on the shape of certain plant cells when the plant dies. Phytoliths of the particular plant stored or processed are often recovered in storage areas and on stone tools that had been used for plant processing.
The earliest macroscopic remains identified so far from an archaeological site include species of wild plum and hackberry found in the Douara cave in the Palmyra basin in Syria; they date to approximately 100,000 years ago. Palynological data (i.e., data for pollen and spores) from western Syria indicate that these species would not have been growing very near the cave but may have been collected at a higher altitude in the nearby hills. Hunter-gatherer populations throughout the Near East collected a variety of plant food resources, including the wild cereals and legumes that eventually were domesticated. The evidence is that agriculture was developed about ten thousand years ago: palynological studies suggest increased aridity then in parts of the Near East; there was a relatively large, settled population in some areas; and new technology in the form of stone sickles made new harvesting techniques possible for wild cereals, which may have, in part, resulted in the selection of domesticated types. Arboriculture, especially of olives, and viticulture were begun in the Levant at least by 3200 BCE or somewhat earlier. There is written evidence that viticulture was exported to Egypt by 3000 BCE, most likely from the Levant.
Paleobotany is used in conjunction with other biological studies, such as zooarchaeology and paleoanthropology, to address questions of ancient subsistence practices, paleonutrition, and paleodiet. Together with geology and geomorphology paleobotany can provide clues to ancient land use, agricultural practices, and the causes of erosion that may have led to the eventual abandonment of an area. For example, a recent study of the wood-charcoal remains from ῾Ain Ghazal in Jordan estimates that deforestation resulted in massive erosion of the arable slopes around the site, thus substantially depleting the potential for agricultural subsistence in the area. The site was abandoned by about 5700 BCE.
- Moore, A. M. T., and Gordon Hillman. “The Pleistocene to Holocene Transition and Human Economy in Southwest Asia: The Impact of the Younger Dryas.” American Antiquity 57.3 (1992): 482–494. Discusses the latest palynological data from Lake Huleh in Israel indicating a period of increased aridity between 11,000 and 10,000 bp. Together with the macroscopic plant remains from the Mesolithic levels of Abu Hureyra in Syria, these data suggest an expansion of steppic vegetation at the expense of forest, a change in plant collecting that led to settlement changes over much of the Levant.
- Pearsall, Deborah M. Paleoethnobotany: A Handbook of Procedures. San Diego, 1989. Complete discussion of all aspects of paleoethnobotany, including their potential to address human-plant interaction through time and attendant significant social and cultural changes.
- Rollefson, Gary O., and Ilse Köhler-Rollefson. “The Collapse of Early Neolithic Settlements in the Southern Levant.” In People and Culture in Change, part 1, edited by Israel Hershkovitz, pp. 73–173. British Archaeological Reports, International Series, no. 508.1. Oxford, 1989. Discusses the results of the authors' analysis of wood charcoal and house construction at Pre-Pottery Neolithic B ῾Ain Ghazal, Jordan, concluding that production of lime plaster and the trees used for structural supports for houses led to deforestation and erosion of arable soil. Intensive agriculture and grazing contributed to the settlement's collapse and dispersal of the population.
- Zohary, Daniel, and Maria Hopf. The Domestication of Plants in the Old World. Oxford, 1988. The most complete compilation of the botanical evidence for domestication of the principal Old World crops, with a discussion of the genetic, geographic, and ecological data and a brief summary of plant remains at the most important Old World prehistoric sites.