Entwicklung von Fichtenverjüngung im Lehrwald Sedrun der ETH Zürich (nördliche Zwischenalpen) | Development of Norway-Spruce Regeneration in the Training Forest of ETH Zurich in Sedrun, Canton of Grisons, Switzerland (Northern Intermediate Alps)
The development of planted Norway-spruce trees as well as the germination and self-seeding of natural regeneration were investigated on various forest locations on the north and south slopes between 1470 and 1800 m above sea level in the training forest of ETH Zurich in Sedrun, canton of Grisons, Switzerland.
IMPACT OF CLIMATIC AND LIGHT FACTORS ON THE GERMINATION AND SURVIVAL OF SILVER FIR ( ABIES ALBA MILL . ) AND NORWAY SPRUCE ( PICEA ABIES L . KARST . ) SEEDLINGS IN SELECTION FOREST
The paper presents results of seeding experiment of sliver fir (Abies alba Mill.) and Norway spruce (Picea abies L. Karst) in the selection forest. There is still a lack of knowledge about the germination and survival of seedlings in the differentiated forests. The experiment was performed in a managed forest with the selection structure. We established 24 sowing plots in the altitude 960−1050 m a.s.l., north exposure. One hundred of germinative seeds were sowed per one 1 m × 1 m plot. The level of direct and diffuse radiation and share of canopy gaps were measured on each of sowing plots. We analyzed the effect of applied tree species, different soil treatment, date of sowing and light environment on the abundance of germinated and survived seedlings. In addition, we studied the impact of climate conditions (average day temperatures and precipitations) on the seeds germination as well. The analysis revealed the direct effect of climate factors on the survival of spruce seedlings. We recorded the precipitation deficiency of 40 mm during the monitored 42 days that closely corresponded with the highest-recorded mortality of spruce seedlings (73 %). In time of the first inventory, the total amount of spruce seedlings was almost twenty-fold higher than the number of germinated firs. However, in time of the last inventory, the abundance of fir seedlings was 3.5 times higher than that of spruce seedlings. The different level of neither direct and diffuse radiation nor openness affected directly the average number of survived seedlings. Kľúčové slová: pokusný výsev, jedľa biela, smrek obyčajný, výberkový les
Geomagnetic Polarity Epochs: Sierra Nevada Data, 3
Available paleomagnetic and radiometric results for about 60 igneous rocks 3.6 m.y. old or less are consistent with the following geomagnetic polarity epoch time scale: Brunhes normal polarity epoch, 0.0 to 0.85±0.15 million years; Matuyama reversed polarity epoch, 0.85±0.15 to 2.4±0.1 million years; Gauss normal polarity epoch, 2.4±0.1 to 3.35±0.1 million years; Gilbert reversed polarity epoch, 3.35±0.1 million years to (?). A brief interval of normal polarity (the Olduvai event) occurs within the Matuyama reversed epoch at about 1.9 m.y., and a brief interval of reversed polarity (the Mammoth event) occurs within the Gauss normal epoch at about 3.06 m.y. Data for twelve units from eastern California and Nevada, reported here for the first time, are particularly useful in defining the Gauss-Gilbert boundary and for recognizing the Mammoth event.