Auswaschung von Nährstoffen durch sauren Nebel aus jungen intakten Fichten (Picea abies)

Leaching of nutrients out of young intact spruce (Picea abies) by acid fog The effect of acid fog on the leaching of minerals and carbohydrates out of needles of five year old spruce trees (Picea abies) was studied. The fogs were prepared from H₂SO₄ and HNO₃ (2:1) with a pH of 2.75 (acid treatment) and 5 (control treatment). The acid fog leached significantly higher amounts of K, Ca, Mg, Mn, and Zn as well as carbohydrates as compared with the control fog. The absolute quantities of minerals leached, however, were low and amounted to only some percent of the minerals generally present in needles. Except Zn, of which the quantity leached was about as high as the Zn needle content. Nevertheless the Zn concentration in the needles treated with acid fog was not lower than the Zn concentration in the control needles suggesting that the lost Zn was quickly compensated by Zn uptake. In the treatments with acid fog damage symptoms appeared at the end of the experimental period. In the older needles a weak chlorosis occurred; from the needles of the 1^st year some turned redish brown. In the acid fog treatments all needles lacked brightness while the control needles looked bright. These symptoms were similar to those under field conditions of older spruce trees with the ?lametta syndrom”?. Electron microscopic investigation revealed that the wax layer of the needles treated with acid fog was badly damaged.