Reaktion von Weisstannen auf ein- bis mehrmaligen Verbiss entlang von Lichtgradienten

Abstract

Response of Abies alba saplings to single and repeated browsing along light gradients Browsing of silver fir (Abies alba) saplings by ungulates is one of the most important issues concerning decreasing regeneration of this tree species. In addition to genetic drivers, environmental factors such as light availability play an important role for the response of a browsed tree. Using an experimental design with fences, we investigated the influence of natural browsing on tree growth along a light gradient. The few fir saplings that responded by flagging up a lateral shoot compensated the browsing induced height difference compared to unbrowsed trees within four vegetation periods. Most firs however reacted with new shoots and remained smaller than unbrowsed ones. The more often a fir sapling was damaged on its terminal shoot, the smaller the tree remained. A positive relation between tree height and light was found only up to a canopy openness of 11%. Mortality over the whole five years was high in low light (<10%) and in forest gaps (>15%), due to desiccation, competition with other plants or browsing (50% of total mortality). We recommend regenerating firs under moderately shaded conditions.

Recovery of Abies alba and Picea abies saplings to browsing and frost damage depends on seed source

“…Further , saplings of A. alba are browsed much more frequently and heavily by ungulates than saplings of P. abies (Kupferschmid, ; Vacek et al, ), which could have led to different genetic selection and thus to differences in the genetic variation in the recovery following browsing. Additionally, recent browsing experiments have already led to recommendations to foresters that A. alba populations producing many buds should be planted at sites with high ungulate density based on the assumption that bud formation of saplings depends on genetically fixed traits (Kolly & Kupferschmid, ). Due to the results obtained by Pinus and Fagus, it remains unclear to what extent, if at all, the recovery of Abies and Picea saplings after different intensities of browsing depends on seed origin.…”

Browsing regime and growth response of Abies alba saplings planted along light gradients

“…However, in other studies, browsing-induced mortality on small A. alba saplings was not only higher under dark canopy conditions but also in small gaps than under moderately shaded conditions (i.e. 10-14 % canopy openness, Kolly and Kupferschmid 2014).…”

Kurzbericht zur Ausgangssituation des Verbisseinflusses im Wisent Thal Projektgebiet

“…Rund 70% der PF waren so dunkel, dass selbst für die schattentolerante Weisstanne das Wachstum der Verjüngung durch Lichtmangel limitiert sein dürfte (vergl. Kolly and Kupferschmid, 2014).…”