Seven geographical locations with at least 15 trees were selected in the Dinaric phytogeographic region. All trees, except dead and clearly dying ones,were analysed. Tree-ring widths were measured on two cores or on one stemdisc. Slovene Dinaric silver fir chronology was built on this basis. It covers the period 1790-1995. Comparison of the Slovene regional chronology with the South German and the Bavarian one revealed moderate visual comparability but not very high statistical values. Growing trends in the local chronologies of differently affected silver firs decline rapidly after the year 1960 and reach their minimum in 1976. Thereafter the radial incrementincreases. Especially weak silver firs were most heavily affected. Inthe last 100 years 11 negative and 9 positive signature years were detected.Warm spring months and moderately warm summer months with above average precipitation are most favourable for the increment. Tree-ring width variability can be explained by response functions in the 30-60% range. This indicates that the method doesnćt always give satisfactory results. In the stem analysis 11 missing rings were dated and identified with the help of the regional chronology. Unappropriate forest management has negative influence onsilver fir increment. A fast reduction of the growing stock below 450 m3/ha can provoke a destruction of selfprotecting mechanisms in the forest site and its mechanical and biological stability is endangered. Silver firs respond to the instability of the forest stand with decrease of increment and reductions of the crown. The amount of latewood decreases acropetally, however this trendcan be modified by secondary crown. The growing rhythm of the juvenile and adult wood is comparable.
|
