Along with monitoring plots and forest inventories, long-term growth and yield experiments are essential for researching forest development. However, only growth and yield experiments provide the possibilities to work with controlled treatment, which allows to assess total growth. Ideally, observation covers the whole rotation time of a forest stand; the slow growth processes in a forest require at least decades of observation.
The focus of forest growth research has changed over time because of ecological and economic changes. New questions arose while others, which were very important a hundred years ago, moved into the background. Describing the experimental designs and goals, measurement instruments and assessment methods, the direction of forest growth research is outlined and some answers found so far are presented.