Crown Damage in Norway Spruce and Silver Fir: Relation to Nutritional Status and Soil Chemical Characteristics in the French Mountains

Abstract

The mineral nutrition status of trees has long been acknowledged as an indicator of chemical stress which may act at the root level (nutrient deficiencies, Al or Mn toxicity) or at the foliar level (accumulation of anthropogenic sulphur, fluoride, chloride, etc.). Foliar mineral analysis (hereafter shortened to “foliar analysis”) has proved a suitable method for characterising tree nutrition (Tamm 1954, Bonneau 1988; Zöttl 1973; Lambert et al. 1983). Threshold values have been suggested by a number of authors for optimal, adequate and deficient nutrition (Table 1). The interpretation of soil analyses is generally more difficult than that of foliar analyses. In earlier studies foliar chemistry was often found to be poorly correlated with soil chemistry, although the influence of parent material is generally obvious. This may be explained by various factors, such as heterogeneity in soil and root development. Nutritional diagnosis has therefore often been based solely on foliar analysis. Recently, especially in relation to research into soil acidification, several ratios of exchangeable cations in soils were presented as being roughly correlated with the corresponding elements in foliage (see e.g. Tomlinson and Tomlinson 1990; Zöttl and Hüttl 1985). Soil solution chemistry is supposed to provide a better picture of the “chemical climate” of a soil, but it is not possible to apply these ad hoc methodologies to a large number of stands (see however the comparative study of several French sites in Dambrine et al. 1995a and Boudot et al. 1995).