Climate change may already threaten Scots pine stands in the Swiss Alps
Martine Rebetez & Matthias Dobbertin
| Résumé |
Large numbers of Scots pine are dying in the dry inner-alpine
valleys of the European Alps; in Switzerland, locally almost half
the Scots pine (Pinus sylvestris L.) population has died since
1995. As Switzerland's temperature has increased at more than twice
the global average in the 20(th) stop century and as most of this
increase has occurred during the last 20 years, we investigated
possible relationships between the dying Scots pine and climatic
parameters. We centred our studies in the upper Rhone valley. Our
results show that the strong climatic warming that has occurred in
recent years may well be the indirect cause of the mortality
observed in these forests. Tree mortality was highest following the
dry and hot year 1998, and tree defoliation, an indicator of tree
vitality, showed a strong correlation with the previous year's
precipitation. While precipitation showed no clear significant
trend over time, the number of warm days (mean >20degreesC, maximum
>25 degreesC) and potential evapotranspiration have significantly
increased over the last 20 years. Higher temperatures favour pine
wood nematodes and bark beetles, both of which are found at the
study site, and increasing drought stress reduces tree resistance
against pathogens. As these forests have in part protective
functions, there is a need to better understand the mortality
through interdisciplinary research and also to find means to change
the species composition in order to establish tree species that are
better able to withstand warmer temperatures. |
| Mots-clés |
BEETLE IPS-TYPOGRAPHUS, WILT DISEASE, NORTH-AMERICA, TREE-RING, TEMPERATURE, SWITZERLAND, SYLVESTRIS, JAPAN, 20TH-CENTURY, VARIABILITY |
| Citation | Rebetez, M., & Dobbertin, M. (2004). Climate change may already threaten Scots pine stands in the Swiss Alps. Theoretical and Applied Climatology, 79(1-2), 1-9. |
| Type | Article de périodique (Français) |
| Date de publication | 2004 |
| Nom du périodique | Theoretical and Applied Climatology |
| Volume | 79 |
| Numéro | 1-2 |
| Pages | 1-9 |