Treeline dynamics in the Swiss Alps: combining dendroecological reconstructions of relict treelines with projections from a forest succession model

• Research unit: COST
• Project number: C13.0056

Key words (English)

Forest dynamics; forest structure; treeline; dendroecology; climate variability; statistical models; forest succession models

Research programs (English)

COST-Action ES1203 - Enhancing the resilience capacity of SENSitive mountain FORest ecosystems under environmental change (SENSFOR)

Short description (English)

The position of high-elevation treelines is mainly controlled by temperature and further modified by factors such as geomorphology and disturbances. To more reliably project future treeline position and structure under global warming, data from long-term reconstructions of tree population dynamics (regeneration, growth, and mortality) are needed, which allow to test and further develop quantitative models of forest dynamics. The objectives of the suggested project are 1) to reconstruct and analyze such forest dynamics in relict forests (i.e. forest outposts); 2) to quantify the relationship between temperature and radial growth rates of the major treeline species along altitudinal transects; and 3) to use these empirical data to improve the formulation and parameterization of the simulation model ForClim, and to project forest succession under current and future climate. The empirical work will be conducted at nine sites in three climatically different regions in the Swiss Alps. Forest dynamics in the forest outposts and growth rates along the altitudinal transects will be reconstructed using tree-ring analysis. Different statistical methods will be used to analyze the population and growth data. The improved ForClim model will be applied under current climate for the sampled forest outposts and along the altitudinal transects, and state-of-the-art scenarios of climate change will be used to assess & quantify the sensitivity of treeline ecotones to future climate variability.

Partners and International Organizations (English)

AT; BG; CZ; FI; DE; EL; IS; IE; IT; NO; PL; RO; RS; SK; SI; ES; SE; TR; UK; US

Abstract (English)

The position of high-elevation treelines is mainly controlled by température and further modified by factors such as geomorphology and disturbances. To more reliably project future treeline position and structure under global warming, data from long-temi reconstructions of tree population dynamics are needed, which allow to test and further develop quantitative models of forest dynamics. The objectives of the suggested project are 1 ) to reconstruct and analyze such forest dynamics, particularly with respect to régénération and growrth, in relict forests (i.e. forest outposts); 2) to quantify the relationship between température and radial grovtrth rates of the major treeline species along altitudinal transects; and 3) to use thèse empirical data to improve the formulation and parameterization of the simulation model ForClim, and to project forest succession under current and future climate. The empirical work will be conducted at nine sites in three climatically différent régions in the Swiss Alps. Température loggers installed at the treeline sites and along the altitudinal gradients will provide exact lapse rates to scale long time séries of température to in-situ conditions. This will allow for a detailed analysis of the influences of past climate variability on forest dynamics at the treeline, especially elucidating différences between the three régions. Forest dynamics in the forest outposts and growrth rates along the altitudinal transects will be reconstructed using tree-ring analysis. Différent Statistical methods will be used to analyze the population and growrth data. The improved ForClim model will be applied under current climate for the sampled forest outposts and along the altitudinal transects, and state-of-the-art scénarios of climate change will be used to assess and quantify the sensitivity of treeline ecotones to future climate variability.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C13.0056