|
|
NATIONALPARK-FORSCHUNG IN DER SCHWEIZ 89 (2000)
Schütz, M.; Krüsi, B.O.; Edwards, .PJ. (eds): Natl.park-Forsch. Schweiz
89, 131 - 164
|
Impacts of snow and ungulates on the successional development of a mountain
pine forest in the Swiss National Park (Munt la Schera)
Der Einfluss von Schnee und Huftieren auf den Sukzessionsverlauf in einem
Bergföhrenwald im Schweizerischen Nationalpark (Munt la Schera)
Bertil O. Krüsi, Barbara Moser
Swiss Federal Research Institute WSL, CH-8903 Birmensdorf, Switzerland
Abstract
Disturbances, such as the snow pressure incident of 11 November 1996, which
claimed 11% of
the healthy trees, or the activities of ungulates, which for decades have attained densities of 40
animals per 100 ha during the summer months, have only marginally affected the past development
of the mountain pine (Pinus montana) stand studied. Likewise, wild ungulates — at least at current
density levels — will also not be able to affect significantly the future successional development,
neither by browsing nor by creating vegetation-free germination sites. In the absence of major disturbances,
the mountain pine stand of 1998 attaining a height of 13 m, with 10% larch in the tree layer, will likely evolve
over the next 150 years into a main stand of similar height, but with Swiss stone pine and mountain pine being
more or less equal in importance; the main stand will be surpassed by about 60 hold-over larch trees per hectare,
attaining between 30 and 35 m in height, and up to 450 years in age. In the 5 m tall secondary stand, two out of
three stems will be Swiss stone pines, in the lower shrub layer (21-130 cm)
three out of four.
The successional development of the stand studied can be influenced substantially only by factors
and incidents that affect the relative competitiveness between the four tree species, mountain pine,
larch, Swiss stone pine, and spruce. Among such factors are diseases, for instance, the ones induced by
parasitic fungi. In the studied stand, however, availability of light in the lower shrub layer appears
to be the crucial factor. Availability of light depends mainly on the evolutionary stage of the stand;
it may, however, be altered substantially also by major abiotic disturbances such as wind throw,
avalanches, or wildfires. The ungulates present in the area — mainly red deer and chamois — can significantly
affect forest succession only under very special circumstances.
Preface |
abstract 1 |
abstract 2 |
abstract 3 |
abstract 4 |
abstract 5 |
abstract 6 |
abstract 7 |
abstract 8 |
abstract 9 |
abstract 10 |
abstract 11
|
![[WSL]](/images/logo3.gif){kind=logo}