Wachstum und Ernährung von Eberesche,Buche und Fichte im Gefäßversuch mit immissionsbelasteten Bodensubstraten aus dem Erzgebirge

Influence of simulated sulphur and nitrogen depositions on biomass and nutrient relationships of mountain ash, European beech and Norway spruce in a pot experiment with two soil substrates from the Ore Mountains Growth and nutrient relationships of mountain ash (Sorbus aucuparia), European beech (Fagus sylvatica) and Norway spruce (Picea abies) were investigated in a pot experiment with the two substrates rhyolithe (acidic) and basalt (alkaline). Additionally, depositions of sulphur (S) and nitrogen (N) as expected to occur in the Ore Mountains (Saxonia, Germany) in the future were simulated in order to test the species′ suitability for forest regeneration. After two years, aboveground biomass was significantly higher on basalt compared to rhyolithe for all species. The amount of S given (0 and 100 kg ha^—1 a^—1) and the dominant form of N applied (NH₄⁺:NO₃^— = 1:4 and 4:1; total amount of N given 80 kg ha^—1 a^—1) were of minor influence only. The contents of N and K in leaves or needles were higher on rhyolithe, whereas P, Ca, Mg and Mn contents were higher on basalt. Nutrient contents were only slightly affected by the amount of S supply and the NH₄⁺:NO₃^— ratio. In contrast to mountain ash, beech saplings exhibited considerable growth on rhyolite. It is therefore concluded that beech may be a suitable species for forest regeneration even on acidic soils suffering heavily from S and N immissions, whereas spruce will not tolerate high S loads. However, increasing N depositions by stimulating growth may cause deficiencies of Mg and K in both species.     

Tree rings indicate different drought resistance of a native (Abies alba Mill.) and a nonnative (Picea abies (L.) Karst.) species co-occurring at a dry site in Southern Italy

Climate changes induced by the anthropogenic alteration of the atmospheric radiative balance are expected to change the productivity and composition of forest ecosystems. In Europe, the Mediterranean is considered one of the most vulnerable regions according to climatic forecasts and simulations. However, although modifications in the inter-specific competition are envisaged, we still lack a clear understanding of the ability of the Mediterranean vegetation to adapt to climate changes. We investigated how two co-occurring tree species commonly used in afforestation programmes, the native Abies alba Mill. and the nonnative Picea abies L. Karst., adapt to climate change by assessing their growth performance and physiological responses in relation to past climate variability. Growth was addressed by analysing tree-ring width and carbon and oxygen stable isotopes. Statistical relationships between isotopic value and monthly climate data suggest that the two species underwent ecophysiological adaptation to Mediterranean climatic constraints. These adaptations are also expressed in the ring-width data. Based on the carbon isotope ratio reflecting the stomatal response to drought, we found that the precipitation in the first period of the growing season, i.e. early spring, is a major factor influencing the annual growth of A. alba, which although native, proved to be sensitive to drought. P. abies, on the other hand, showed a higher tolerance to summer drought stress. These findings should help define criteria for sustainability and effective forest conservation in the Mediterranean region.     

Einsatz von Kennzahlen und Beratungsbriefen als Controlling-Instrument für Beratung und Gartenbaupraxis an der Niederelbe

The first business management analyses of fruit farms from the Altes Land (Lower Elbe Valley, Northern Germany) date back to the financial year 1956/57 and were published in 1958 by Prof. A. Löhden in the journal Mitteilungen des Obstbauversuchsringes des Alten Landes e.V. The data compiled by Löhden from the Agrarian Report were used by the Chamber of Agriculture of Hannover to evaluate the book-keeping of those fruit farms which it supported with business development grants. In the early 1980s the fruit advisory services had to implement a comparison of the book-keeping data of fruit farms. This business management advice has been expanded subsequently. At present, some 120 fruit farmers participate at the annual comparison of the Fruit Advisory Service and the Centre of Business Management in Horticulture. The use of this controlling instrument for evaluating key business data will be demonstrated in the current article on the basis of two examples.