This standard represents the framework of the series of standards VDI 3957. It introduces the subject of the series "biomonitoring with plants". It presents the contents of both the 15 method descriptions already standardised and the on-going standard projects. In addition, the standard includes an overview of potential scopes of application for biological measuring techniques as well as essential information concerning quality assurance and documentation. Furthermore, it provides definitions of important terms. The standardised biological measuring techniques described allow to determine the temporal and spatial distribution of the effects of air pollutants and, using assessment values, to evaluate the endangerment for plants and - via the food chain - for animals and humans.