(View exact match)arborealCATEGORY: flora
DEFINITION: Concerning trees. In pollen analysis, arboreal pollen types are distinguished from shrub pollen and herbaceous pollen.arboreal pollenCATEGORY: flora
DEFINITION: Pollen from trees.nonarboreal pollenCATEGORY: flora
DEFINITION: Pollen from nontree plants, such as sedges and grasses.
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pollen analysisSYNONYMS OR RELATED TERMS: palynology
DEFINITION: The study of pollen grains in soil samples from an archaeological site which provides information on ancient human use of plants and plant resources. This technique, which is used in establishing relative chronologies as well as in environmental archaeology, was developed primarily as a technique for the relative dating of natural horizons. Pollen grains are produced in vast quantities by all plants, especially the wind-pollinated tree species. The outer skin (exine) of these grains is remarkably resistant to decay, and on wet ground or on a buried surface, it will be preserved, locked in the humus content. The pollen grains of trees, shrubs, grasses, and flowers are preserved in either anaerobic conditions or in acid soils. Samples can be taken from the deposits by means of a core or from individual layers at frequent intervals in a section face on an archaeological site. The pollen is extracted and then concentrated and stained and examined under a microscope. Pollen grains are identifiable by their shape, and the percentages of the different species present in each sample are recorded on a pollen diagram. A comparison of the pollen diagrams for different levels within a deposit allows the identification of changes in the percentages of species and thus changes in the environment. As a dating technique, pollen has been used to identify different zones of arboreal vegetation which often correspond to climatic changes. The technique is invaluable for disclosing the environment of early man's sites and can even, over and series of samples, reveal man's influence on his environment by, for example, forest clearance. The sediments most frequently investigated are peat and lake deposits, but the more acid soils, such as podsols, are also analyzed. Radiocarbon dates may be taken at intervals in the sequence, and it is possible to reconstruct the history of vegetation in the area around the site where the samples were taken. Palynology plays an important role in the investigation of ancient climates, particularly through studies of deposits formed during glacial and interglacial stages of the Pleistocene epoch.proportional pollen countingCATEGORY: technique
DEFINITION: A type of pollen analysis carried out by determining the proportion of different pollen types in each sample. Proportions are usually expressed as percentages of total tree (arboreal) pollen. This method is fairly quick as only a fraction of the grains present in a sample need be counted. Its main disadvantage is that percentages can never indicate actual numbers of grains falling to earth, which is solved by Absolute Pollen Counting.