Effects of Atmospheric Nitrogen Deposition in Forest Stands: Recognizing the Consequences by Foliar Analysis : Causes and Consequences of Accelerating Tree Growth in Europe. Proceedings of the International Seminar

1999

S. 17-23

7 Abb., 13 Lit

Unselbständiges Werk

200058981

A nitrogen (N) cycle model shows that only a part of the total deposition is useful for stand nutrition because a major part of the winter deposition is lost in the drainage water. Nitrogen deposition can be beneficial to forest nutrition only if nitrogen was a limiting element before the period of high deposition, as was the case in France between 1960 and 1970, or even more recently, in some forest stands. Several fertiliser experiments demonstrated that when major elements other than nitrogen are supplid in sufficient amounts by the soil, the effect of N fertilizer, and thus probably of N deposition, is positive. However, when the supply of an other element is limited too, the effects of nitrogen fertiliser or deposition may be noxious. Foliar analysis might be a good tool for recognizing effects of N deposition but this method is limited by the high interannual fluctuation of the N concentration in the leaves or needles. For this reason, it is necessary to perform foliar analysis every year in the same stands. In addition, this continuous analysis has to be performed in mature stands: in young stands, the effect of N deposition may be hidden by the evolution of the needle or leaf composition due to stand ageing.