FOREST: Forest response to environmental stress at timberlines

• Research unit: EU RFP
• Project number: 95.0431-2

Key words (English)

Gis; bioclimatic data; tree-reing; tree line; tree distribution; modeling; static; Work packages V; Activity 1(Dendroclimatology) and VI (Numerical analyses and climate modelling)

Alternative project number (English)

EU project number: ENV4-CT95-0063

Research programs (English)

EU-programme: 4. Frame Research Programme - 3.1 Environment

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
Eidg. Forschungsanstalt für Wald, Schnee und Landschaft WSL

Abstract (English)

The Polar and the Alpine forest-lines and tree-limit are expected to alter its properties under changing climate regimes. This effect can be monitored and measured at the present day but the duration of any such monitoring is usually too short to reveal real trends. Thus it is necessary to supplement ongoing monitoring efforts with paleoecological records on past vegetation shifts and to develop ecological models to assess the potential future development.
The Swiss FOREST regional group provides three modules to identify key factors that determine the risks of global warming onto tree species in an alpine environment:
Dendroecology, Palaeoecology and Ecological Modelling. The module Dendroecology provides well-dated annual information on the site-specific relationship between climate and tree growth. Results are valid on high temporal resolution but only on a limited area ranging from approx. 1 to 50 km. Corresponding risk assessments estimate impacts of warming on tree growth on a local scale. Implications of the module Palaeoecology integrate various spatial and temporal scales. Pollen records have local, regional and supra-regional character at the same time, depending on the species and on the site. As pollen records are often dated with ranges of uncertainty of several years, the relationship between climate and (tree) pollen distribution has a rather broad-scale character in space as well as in time. The module Ecological Modelling developed a spatially explicit equilibrium model of individual species occurrence. It identifies the areas that are possibly affected by changes in tree distribution due to warming and evaluates the magnitude of the changes along a biotemperature gradient. Model predictions have broad-scale character and are valid on a regional scale. Moreover, the model is independent of the response-time of tree species to warming as it suggests equilibrium conditions between climate and tree species occurrence. Links between the modules allow interdisciplinary syntheses of the relevance of climate for tree species: (a) Identifying past behaviour of tree species: Palaeoecology and Dendroecology. Here we checked whether the pollen influx (regional signal) and the ring width of dendroecologica1 data (local signal) show comparable responses to climate fluctuations. (b) Learning for the future from the past: Links between Palaeoecology and Modelling. With this study we validated model predictions about potential species distribution under today's climate with pollen records for today's conditions. In a second step we used the relationship as a helpful tool to evaluate alterations of tree distributions during Holocene climatic oscillations. Based on the results implications for potential future tree distribution changes are assessed.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 95.0431-2