Can the age of herbs, dwarf shrubs and shrubs be determined, and if so, how old can they get? And what possibilities exist for answering ecological questions about plants and populations using the ages of such plants? These and many more questions prompted us to analyse the growth rings observed in central European herbs, dwarf shrubs and shrubs, and also, more generally, to review the state of the art for classifying and determining the age of plants. We also explore 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. We present techniques and prerequisites for identifying growth rings and for validating that they are actually annual rings. The limitations of growth-ring analysis are discussed. The anatomy of the root collars of about 800 central European species is given.
The methods of age classification/determination reviewed include: annual ring and other chronological methods, growth form analysis, permanent plot research, and historical and genetic analyses.
The application of growth-ring analysis to describe population structures allows the current status of a population to be assessed. Several examples are given. Physiological and environmental factors that may limit a plant's lifespan are reviewed. Preliminary results evaluating our data set show that lifespan may be limited by temperature and nutrients.

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