Stahl was born in Schiltigheim to timber merchant Christian Adolf and Magdalene née Rhein.

The Franco-Prussian War of 1870-71 made him move to the University of Halle where he studied under Anton de Bary (1831-1888).

[1][2][3] Stahl is remembered for his pioneer experiments in the field of ecophysiology, as well as research involving the developmental history of lichens.

[1] Stahl travelled to Algeria in 1887 and in 1889-90 he visited Ceylon and Java with Andreas Franz Wilhelm Schimper (1856–1901) and George Karsten (1863–1937).

He conducted important research on the symbiotic relationship between mycorrhizal fungi and tree roots, and also worked on plant defense against snail and slug herbivory[5] and a plethora of other botanical and ecological questions.