[4] It was from this latter institution that he earned his doctorate degree in 1952, defending a thesis titled "Heat and drought tolerance of lichens in relation to their geographic distribution".

[4] From 1963 to 1967 he held the chair for Forest Botany and Technical Mycology at the University of Göttingen and was responsible for the Forestry Botanical Garden and Arboretum there.

[6] During Lange's 25 years at the University of Wurzburg he alternated long periods in the field with work analysing results back at the lab and writing scientific papers.

[2] The aim of his ecological-botanical research was to quantitatively record the behavior and reactions of wild and cultivated plants, as well as of lichens in their outdoor locations in the interplay with their environment.

A constant change between measurements and experiments in the field and working under controlled conditions in the laboratory, for example in climatic chambers, was characteristic of such ecophysiological investigations.

In cooperation with specialist companies (in particular, Heinz Walz GmbH), Lange developed special instruments, for example, air-conditioned cuvettes, and "porometers" to determine gas exchange and diffusion resistance of plants and lichens.

[3] Lange was editor and co-editor of (Photosynthetica (1967–1995), Oecologia (1970–2007), Flora (1964–), Biochemie und Physiologie der Pflanzen, Trees (1986–1998), Botanica Acta(1987–91)),as well as the book series (Ecological Studies,[3] Man and the Biosphere Programme) and specialist books (e.g. 4 volumes of the Encyclopedia of Plant Physiology: Physiological Plant Ecology, Springer-Verlag 1981–1983).