Below-canopy climate and climate trends
Microclimate is a key factor influencing regeneration in forests. Particularly available light, water supply and temperature determine the success or failure of certain tree species. How will future climate change influence below-canopy microclimate and tree regeneration?
Forest microclimate is influenced by canopy cover and the presence of tree stems. Forested areas generally cool down less during night and limit daytime air warming. This is partly because turbulence and thus mixing of air are reduced when compared to the surrounding open area. Forest influences the quantity and patterns of precipitation and light reaching the ground. Besides these impacts of forest structure coniferous woodland generally shows greater spatial variations in microclimate than broadleaved woodland.
Increasing global temperature and changing frequency of extreme weather events will impact below-canopy microclimate and consequently future species composition of forests. It is thus essential to gain deeper insight into how forest structure and projected climate change alter below-canopy microclimate in order to determine the most sensitive forest ecosystems.
- Quantifying the relationships between local weather and below-canopy microclimate considering different influencing factors
- Projecting future below-canopy microclimate in different types of Swiss forests
- Determining the effects of below-canopy microclimate changes on future species distribution ranges
- Assessing the effects of below-canopy microclimate on forest regeneration
The study focuses on 14 Swiss LWF forest sites located in all biogeographic zones of Switzerland. They comprise deciduous, coniferous and mixed forests. We will use
- continuous meteorological site data collected in open field and below-canopy (since 1997)
- tree positions and tree dimensions (stem diameter, tree height, crown length and crown size)
- leaf area index measures
- different soil parameter (e.g., soil water potential and water content, soil temperature, matric potential and volumetric soil moisture content).
- Several statistical approaches will be used to understand and quantify the interactions between ecosystem processes and meteorological parameters.
Expected scientific results
This project will help to estimate the range of climate change to be expected in Swiss forests. We wish to quantify future weather extremes (temperature, precipitation, humidity) in different forest ecosystems with different characteristics as to species composition, stand structure, orientation, altitude and soil. The goal is to better understand microclimatic effects and their impact on natural regeneration.
This study will contribute to an improved understanding of the impact of silvicultural practices on the microclimate in the forests. It will thus allow recommendations for forest management to minimize the effects of climate warming in the forests and to optimize practices for forest regeneration.