| Forest Foliar Condition in Europe - National Report Austria |  |
In the framework of the Austrian Forest Damage Monitoring System the Federal Forest Research Centre is investigating Austria's forest conditions. Among others, crown assessments, growth studies, soil investigations, but also foliar analyses were made.
Methods
About 80 (1989: 86 plots; until 1995: 80 plots) of the approx. 270 plots where foliar analyses were carried out are situated on the transnational grid for Level I evaluation. Since 1989 all plots were sampled annually, either in September or in October; samples were taken by climbers.
After the sampling process samples were dried, wooden parts were removed and ground. Leaves type 0 and, in the case of conifers, also leaves type 1 was analyzed separately for all three sample trees. Sulphur and nitrogen were determined by means of an elementary analyzer (LECO SC-432; CNS-2000). Phosphorus, potassium, calcium, magnesium, iron, manganese, and zinc were after open sulphuric acid/nitric acid digistion analyzed by using ICP-AES (Varian - Liberty 200).
Results
The results were interpreted at national level using either the legal limits applicable in Austria [1] or assessment values from literature [2, 3, 4]; this explains the differences compared to the uniform assessment values of the FFCC.
Wide-spread effects of sulphur pollution were found only in the north (Waldviertel and Mühlviertel) and in the south-east of Austria (Lavanttal, south-east of Styria) as well as in the Mur/Mürzfurche. In connection with the effects of sulphur pollution also the nutrient ratios should be considered, particularly the S/N ratio [5].
Between 1989 and 1992 the nitrogen deficiency increased from approx. 50% to 75% for [6]; after that, the nitrogen deficiency decreased to less than 50%. A major part of the deterioration found until 1992 was observed in the north of Austria (Upper and Lower Austria).
In the area of the Limestone Alps phosphorus deficiencies of up to 15% were found. As 1992 was an extremely dry year, more than 5% of the plots showed a magnesium deficiency then - especially in Upper Austria. Also in Upper Austria, several plots near the river Danube were poorly supplied with zinc. Some plots showed a potassium deficiency. On the other hand, the supply of trees with calcium, iron and manganese has not proved problematic in Austria.
Annual sampling showed that years with extremely dry vegetation periods (e.g. 1992) significantly influence the nutrient content of needles and leaves [7].
As a further step of evaluation, it was also tried to combine soil and needle data. Interesting connections were found in the case of manganese. On calcerous sites, there is a significant correlation between the manganese content of needles and the pH value of the soil. On non-calcerous sites, the manganese content depended on the total supply of the soil. In transition areas in respect of the pH-value between the two above-mentioned soil-typs, a connection was found between the manganese content of the needles and that of the soil solution [8].
References
[1] Zweite Verordnung gegen Forstschädliche Luftverunreinigungen. Bundesgesetzblatt Nr. 199/1984.
[2] GUSSONE H.A. 1964: Faustzahlen für die Düngung im Walde. BLV-Bayerischer Landwirtschaftsverlag, München-Basel-Wien, 98 S.
[3] BERGMANN W. 1993: Ernährungsstörungen bei Kulturpflanzen: Entstehung und Diagnose. Gustav Fischer Verlag, Stuttgart.
[4] FOERST K. & SAUTER U. & NEUBURG W. 1987: Bericht zur Ernährungssituation der Wälder in Bayern und über die Anlage von Walddüngungsversuchen. Forstliche Forschungsberichte München 79. p.7.
[5] FÜRST A. 1992: Die Bedeutung des Schwefel-/ Stickstoffverhältnisses für die Beurteilung des Ernährungszustandes von Fichten. FBVA Berichte 71/1992. 51-54.
[6] FÜRST A. 1996: Blatt- und nadelanalytische Untersuchungen im Rahmen des Waldschaden-Beobachtungssystems - Ergebnisse 1989 bis 1993. FBVA-Berichte 93/1996. 101-109.
[7] FÜRST A. 1996: Eisen-, Mangan- und Zinkversorgungsgrad der Fichte im Jahr 1993 in Österreich. FBVA-Berichte 93/1996. 111-120.
[8] GABLER K. & FÜRST A. & MUTSCH F. 1996: Manganese Supply of Spruce in Austria - Connections between Soil and Needle Content. 26th International Symposium on Environmental Analytical Chemistry TU-Wien 9-12.4.1996.