The nutritional status of Austrian forests and its development over two decades, based on the Bioindicator Grid

Essen

2005

S. 71

Monographie

9727S

128378

Since 1983 the nutrients nitrogen, phosphorous, calcium, magnesium and postassium are analysed at 282 sampling plots within the basic grid and at 755 plots within the total grid, covering the total forested area of Austria. The needle year 1 of two sample trees per plot is analysed and the main tree species is Norway spruce which covers 95 % of the plots. According to the ranges of Gussone (1964) for "sufficiently supplied", "insufficiently supplied" and "deficiency", the nutrient status was evaluated and regionally and annualy differentiated. The data are available on the homepage of the Federal Office and Research Center of Forests (Austria: www.bfw.gv.at/600/1003.html). Also small areas such as local districts can be called up regarding information about nutrients and particular years. For 2002, 88 % of the plots were in the range of "insufficiently supplied" or showed "deficiency". The development of the nutritional status during the last 20 years showed a worsening situation which differed in the respective growth areas. Contrary to the nitrogen satus, the needles were more adequately supplied with phosphorous, calcium, magnesium and potassium.