Untersuchungen über die Salzverträglichkeit verschiedener Pappel-und Weidenarten sowie -klone unter Labor- und Freilandbedingungen

The salt tolerance of various poplar and willow species and clones in the laboratory and field. The resistance of 10 black and 10 grey poplar clones and of 36 willow clones was examined by dipping shoots in a higly concentrated NaCl solution. All the black and most of the grey poplars showed high resistance. Only eleven willow-clones showed sufficient resistance. The studies are to be continued with enlarged material under various ecological conditions.     

Wundfäule in Fichtenwaldungen mit alten Schälschäden

Wound decays in spruce stands following bark stripping . 2083 trees in 91 sample plots on four trial areas (24 ha) were examined for bark stripping and decay. Only 25% of trees showed no injury. Of the injured trees, 73% showed some degree of decay, 10% discoloration. and 17% neither decay nor discoloration. Of the wood destroying fungi isolated Fomes annosus was dominant and appeared to be the most important and widespread of the wound inhabiting fungi in the test area. Besides the Basidiomycetes a considerable number of other fungi was isolated. The most frequent was Cylindrocarpon cylindroides var. tenue.     

Untersuchungen über Potebniamyces coniferarum in den Niederlanden

Research on Potebniamyces coniferarum in the Netherlands . A review of research done in the Netherlands on the fungus Potebniamyces coniferarum, the cause of the Phomopsis disease of Douglas fir and Japanese larch, is given.     

Infektionsversuche mit Rhizosphaera kalkhoffii und Lophodermium piceae an unterschiedlich gestreßten Jungfichten (Picea abies [L.] Karst.)

Young spruce trees [Picea abies (L.) Karst.] artificially inoculated with Rhizosphaera kalkhoffii B. and Lophodermium piceae (F.) v. H. were exposed to fumigations with O₃ and SO₂ and drought. These treatments showed no influence on the infection-rates of the fungi. R. kalkhoffii proved to be a saprophyte living for a long period as an epiphyte on the needle surfaces.     

Biochemische Veranderungen in jungen Birken im Nahbereich einer Autobahn

Biochemical changes in young birches in the vicinity of a highway. In spring 1975 clonal birchtrees (grafts) were exposed to polluted air at different distances from a highway. After three months’ ex-posure, leaves showed different concentrations of free amino acids, total phenols, chlorophyll a, chloro-phyll b, (3-carotene, reducing sugars and total content of vitamin C depending on distance from the highway. Also the lead concentration in moss filters showed an approximately exponential decrease with distance from the highway.     

Die gegenwartige Epidemie des Tannensterbens

The present epidemic of dying of silver fir. Its geographical distribution in the northern part of the natural distribution of Abies alba . Dying of silver fir, a complex disease phenomenon of Abies alba which has recurred periodically for more than a century and which is still unexplained, has been especially serious in recent years north of the Alps. Based on disease symptoms in the crowns, the present distribution of the disease is shown and described on a map. The necessity for increased inter-national cooperation is stressed.     

Seasonal fluctuations of starch in root and stem tissues of coppiced Salix viminalis plants grown under two nitrogen regimes

Seasonal changes in starch were studied at the tissue and cellular levels in roots and stems of Salix viminalis L. cuttings. Cuttings were planted in pots containing sand and grown in a controlled environment chamber in which seasons were artificially induced by changes in temperature and photoperiod. Nitrogen was supplied at optimum and low rates, and during dormancy, one-half of the plants were decapitated. Starch concentrations in root and stem tissues were determined regularly during shoot extension growth, dormancy and resprouting after dormancy. We used light microscopy (LM) combined with image analysis (IA) to determine the cellular localization and amount of starch in different cell types of stem and root tissues. Chemical analysis confirmed that starch concentrations were lower in plants receiving a high-N supply rate than in plants receiving a low-N supply rate. In all plants, the highest concentration of starch was in the roots. Light microscopy and IA showed that starch accumulated mainly in the phloem and cortical cells of both root and stem tissues. Starch grains were also regularly found in ray parenchyma cells. The amount of starch as well as the size of the grains showed strong seasonal fluctuations. In both roots and stems, starch concentrations were highest during predormancy and lowest during periods of shoot extension growth. At the time of resprouting, root cells of decapitated plants were more depleted of starch than root cells of intact plants, supporting the hypothesis that starch reserves in roots are important during the early phase of resprouting in coppice systems.     

Beziehungen zwischen der Ausbreitung künstlicher Fomes annosus-Infektionen in den Stämmchen zweier Fichtenklone und einigen holzchemischen Eigenschaften

The spread of Fomes annosus from artificial infections of stems, in relation to the chemical characteristics of timber of two spruce clones . Differences in the spread of Fomes annosus in two spruce clones (Picea abies Karst.), which were found by DIMITRI, may be attributed to differences in the properties of the wood from the two clones, detected in laboratory tests. Wood meal from the more resistant clone R inhibited Fomes annosus in bioassays more than wood meal from the more susceptible clone A. Wood from clne A-trees showed a higher nitrogen content than wood from clone R-trees.