Search results for "forest"
showing 10 items of 3780 documents
The accumulation of proline in needles of damaged spruces
1985
Im Rahmen einer vergleichenden physiologischen und cytologischen Charakterisierung geschadigter und schadsymptomfreier Fichten am naturlichen Standort wurden im Spatsommer und Herbst 1984 erste Untersuchungen zum Wasserhaushalt der Baume durchgefuhrt. Messungen des Gesamtwasserpotentials, des osmotischen Potentials, des Gehaltes an verschiedenen Kohlenhydraten und an der freien Aminosaure Prolin deuten auf Veranderungen im Wasserhaushalt geschadigter Fichten. Besonders signifikante Ergebnisse waren beim Prolin zu verzeichnen. Wahrend bei den symptomfreien Fichten der Prolingehalt der Nadeln ungeachtet des Standortes und der Witterungsverhaltnisse konstant niedrig lag, trat bei Schadigung ei…
Responses of polypore fungi following disturbance-emulating harvesting treatments and deadwood creation in boreal Norway spruce dominated forests
2019
ABSTRACTThe emulation of natural disturbances in harvesting has become a widely accepted approach to reach ecologically sustainable forest management. The purpose of this study was to examine the r...
Influence of wood harvest on tree-ring time-series of Picea abies in a temperate forest
2012
Tree-ring width data are the prime source of high-resolution climate reconstructions covering recent mil- lennia. Their variations, from year-to-year, are calibrated against regional instrumental data to evaluate the strength of associations with temperature and precipitation records, though the level of variance explained by climatic variables is frequently less than 50%. Among the remaining factors affecting tree growth, the influence of forest management for tree-ring width time-series used to resolve annual climate reconstructions remains relatively unexplored. We here evaluate the impact of conventional single-tree harvesting on tree-ring data using a compilation of circumstantially ma…
Certhia tianquanensis Li, a treecreeper with relict distribution in Sichuan, China
2002
Certhia tianquanensis Li, 1995, is characterised as a distinct species and is combined withC. discolor in the superspeciesC. [discolor]. This probably relict species occupies an extremely small range, and has so far been found at only four sites in western Sichuan, China. It is characterised by a long tail (likeC. discolor), an extremely short bill (similar toC. nipalensis), the patterning on the underside, with white chin and throat and beige chest and abdomen (likeC. himalayana), a striking voice (clearly different fromC. discolor and all otherCerthia species), and a large genetic distance fromC. d. discolor in the cytochrome-b gene. Unlike its closest relativeC. discolor, C. tianquanensi…
Holocene vegetation and fire dynamics in the supra-mediterranean belt of the Nebrodi Mountains (Sicily, Italy)
2012
High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous (Quercus cerris, Fagus sylvatica and Fraxinus spp.) and evergreen (Quercus ilex) species. Species-rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifoli…
Long-term dynamics of Collembola in a pine forest ecosystemProceedings of the Xth international Colloquium on Apterygota, České Budějovice 2000: Apte…
2002
Summary Biomonitoring data on soil Collembola collected over a six year period (1992-1997) in Scots pine ( Pinus sylvestris L.) forest in the Northern Vidzeme Biosphere Reserve, northern Latvia, are analysed. Monitoring was conducted in three plots: young (30-40 years), middle-aged (50—70 years), and old (150—200 years) pine stands. Sampling was performed once a year, in late August or early September, according to a systematic sampling scheme. One hundred soil cores (5 cm 2 × 10 cm) were taken within each plot every year, Collembola were extracted from the cores by using a modified high gradient extractor. During the monitoring period, there was a tendency of climate warming between 1992 a…
Efficient gene therapy based targeting system for the treatment of inoperable tumors
2012
Background A considerable percentage of tumors are not amenable to surgery. We have designed a simple and powerful targeting system that offers an alternative option for the multi-component pre-targeting strategies used clinically. This targeting system can be used for any type of solid tumors independent of the tumor type, thereby omitting the need to engineer unique antibodies for each specific application or tumour type. In the present study, we show the expression of a chimeric fusion protein, which contains the low-density lipoprotein receptor transmembrane domains and avidin, after local gene transfer and its ability to bind biotinylated compounds in vivo. Methods Semliki Forest virus…
Micropropagation of Genista aetnensis [(Raf. ex Biv.)DC]
2015
Genista aetnensis [(Raf. ex Biv.)DC] is a large deciduous shrub or small tree native to the Italian islands of Sardinia and Sicily. Being winter hardy and characterized by high plasticity in altitude and ecology, the species is grown in gardens and landscaping, both for flower and for its attractive shape. Genista species are generally propagate by seed or semi hardwood cuttings. In this report an efficient in vitro technique for propagation of G. aetnensis was investigated. Multiple shoots were induced on nodal segments of a mature plant of Genista aetnensis . The Murashige and Skoog medium, augmented with different concentrations of benzyladenine either singly or in combination with indol…
Gravity-Driven Infiltration and Subsidence Phenomena in Posidonia oceanica Residues
2019
A simplified infiltration model for highly permeable porous media was introduced, assuming the matric potential gradient as negligible compared to the gravitational gradient. This model enabled us to determine the delay time, i.e., the time that the water front takes (from the beginning of rainfall) to reach the bottom of the highly permeable layer. Posidonia oceanica (Linnaeus) Delile residues were used as a porous media, in order to study the infiltration process that provides salt leaching under natural rainfall when these residues are arranged in a storage area, before reusing. By using a laboratory rainfall simulator, delay times were measured to verify the applicability of the aforeme…
Radon levels in the Valencian community (Spain). I. Results in the province of Valencia (1990–1991)
1995
Abstract Two-day radon screening measurements with charcoal canisters were made in buildings in the province of Valencia throughout the years 1990 and 1991. An average indoor concentration of 34 Bq m −3 was found, and 9% of all measurements exceeded the recommended EPA limit of 148 Bq m −3 .