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.
Zu wenig Verjüngung im Schweizer Gebirgs-Fichtenwald: Nachweis mit einem neuen Modellansatz | A new modelling approach suggests insufficient regeneration in Swiss Norway spruce mountain forests
A be-value for tree regeneration cover was derived from a static model of a Norway spruce mountain selection forest and published data. If those assumptions that seem most realistic are adopted in the model, the be-value is 10% cover. According to data from the second Swiss National Forest Inventory, some 55% of the mountain forests in Switzerland with Norway spruce dominance do not meet this be-value. Due to the uncertainty of several assumptions in the model it is not possible to quantify precisely the lack of regeneration, but the extent of insufficient regeneration has been shown to be considerable. Abstract: Mit Hilfe eines statischen Gebirgsplenterwald- Modells und von Daten aus der Literatur wird fur den Gebirgs-Fichtenwald ein Sollwert des Jungwald-Deckungs- grades abgeleitet. Bei plausibel scheinenden Modellan- nahmen liegt der Sollwert bei 10%; er wird in rund 55% des Fichten-dominierten Gebirgswaldes in der Schweiz unter- schritten, wie ein Vergleich mit Daten aus dem zweiten Landesforstinventar zeigt. Einige Modellannahmen sind zwar unsicher und daher ist das genaue Ausmass des Verjun- gungsmangels unbekannt. Es wird aber nachgewiesen, dass dieser erheblich ist.
Physical characterization of seed microsites--movement on the ground.
1. A dispersed seed must remain in a microsite long enough to imbibe water and germinate. Here the post-dispersal movement caused by wind of four asymmetric samaras of Picea engelmannii, P. abies, Pinus contorta var. latifolia and P. strobus was studied on four surface roughnesses (a smooth board, c. 250 μm, c. 750 μm and 2.0 mm). A mechanistic approach is taken to determine the chance that a seed will remain on a surface long enough to germinate. 2. The threshold or lift-off velocities for all combinations of four samaras and four surface roughnesses were determined in a wind tunnel