Stemflow as a canopy water-balance closure term at the first international forestry congress: An English translation of Carl Eduard Ney’s (1893) Ueber die Messung des an den Schäften der Bäume herabfliessenden Regenwassers

Stemflow is now recognized as a hydrologically consequential pathway, yet much of twentieth-century forest hydrology treated it as negligible. This paper revisits a counterpoint, a formal exchange regarding stemflow between Government and Forestry Councilor C.E. Ney and Imperial-Royal Trainee Dr. E. Hoppe at the first Congress of the International Union of Forestry Research Stations (Mariabrunn, 1893; published 1894)—presented here in a complete English translation. Ney argued that “interception-by-difference” (subtracting beneath-canopy throughfall from open precipitation) yields a misleading residual if stemflow goes unmeasured. Hoppe extended this critique, emphasizing spatial variability beneath crowns, wind-driven sampling artifacts, and event structure as controls on precipitation partitioning, culminating in a proposed (labor-intensive) station design. Ney’s closing synthesis affirmed Hoppe’s reasoning while advocating an operationally minimal correction for long-running networks. The paper’s principal contribution is the complete English translation of the exchange, accompanied by a brief contextual introduction.