Heikki Hänninen was born in Laukaa, Central Finland, in 1957. He studied ecology in Jyväskylä and forest science in Joensuu, where he received his PhD in 1990. He worked in various positions at the University of Joensuu (currently part of the University of Eastern Finland) until his appointment to Professor of Terrestrial Plant Ecology at the University of Helsinki in March 1997. Professor Hänninen’s main research interest is the seasonality and climatic adaptation of northern plants, with the assessment of the effects of the projected climatic change as the principal domain of application in his research work. During his early career he worked with forest trees, but after moving to Helsinki he broadened his scope to cover other plant life forms as well. Throughout his career, the combining of experimental ecophysiology with dynamic modelling has been a leading theme in Professor Hänninen’s research. He is a member of the Editorial Review Board of Tree Physiology.