Project description B4 - Project completed
Scientific advisors
Prof. Dr. C. Leuschner, Dr. V. Horna
Project
Water turnover in species-rich and species-poor deciduous forests: Water uptake, xylem sap flow and canopy transpiration
PDF
This project investigates the flows of water through the SPAC (soil-plant-atmosphere-continuum) in broad-leaved forest stands differing in tree diversity. For mono-specific stands (beech), moderately diverse stands (beech, linden and ash) and highly diverse stands (beech, linden, ash, maple and hornbeam) we record the water demands (at different time scales) of the different tree species and differently diverse stands for several years. Furthermore, mechanisms in regulation of water use of these tree species as a response to different abiotic conditions are investigated.
Aims of this project are:
- Quantifying of daily, seasonal and annual sums of canopy transpiration and canopy conductance of the stands varying in tree diversity
- Determination of species-specific differences in water transport and hydraulic architecture (e.g., xylem sap flux density, radial sap flux patterns, xylem structure)
- Impacts of microclimate, soil water, functional-morphological/-anatomical and biometric parameters on water use of these tree species as well as on the stands varying in diversity
- Determination of leaf conductivity, leaf water potential, δ13C in leaves and hydraulic conductivity to address species-specific regulatory mechanisms in evaporative demand
- Balancing the hydrologic cycle at stands varying in tree diversity (in cooperation with project B3)
Methods
- Granier‘s thermal dissipation method (Granier 1985, 1987) for xylem sap flux density measurements
- Mobile canopy lifter for canopy access (max. 30 m)
- Porometry LiCor 1600 for measurements of leaf conductivity and transpiration at leaf level
- Scholander pressure probe for leaf water potential determination (predawn, noon)(Scholander et al. 1965)
- Sapwood area determination via dye injection method (Goldstein et al. 1998, Meinzer et al. 2001), wood core sampling
- Measurement of microclimate (air humidity, air temperature at 2 m height, within the canopy and above of the canopy (add. irradiance))
- Determination of soil water content via TDR- (this project), FDR - and tensiometer-measurements (project B3)