Growth rings in herbs and shrubs: life span, age determination and stem anatomy

Can the age of herbs, dwarf shrubs and shrubs be determined, and if so, how old can they get?\nAnd what possibilities exist in answering plant and population ecological questions by using the ages of such plants? These and many more questions prompted analyses to detail growth rings observed in central European herbs, dwarf shrubs and shrubs; and also more generally, to review the state of art in how the age of plants can be classified or determined, how the knowledge of the presence of growth rings can be applied to ecological and biological conservation questions, and which factors may limit the lifespan of plants.\nWe present techniques and prerequisites to identify growth rings and then to validate that they are actually annual rings. Limitations of growth ring analysis are discussed. The anatomy of the root collars of about 800 central European species is presented.\nMethods of age classification/determination reviewed include: annual ring and other chronological methods, growth form analysis, permanent plot research, and historical and genetic analyses.\nThe application of growth ring analysis to describe population structures allows the current status of a population to be assessed. Several examples are given.\nPhysiological and environmental factors that may limit a plant’s lifespan are reviewed.\nPreliminary results evaluating our data set show that lifespan may be limited by temperature and nutrients.