Available Energy Partitioning During Drought at Two Norway Spruce Forests and a European Beech Forest in Central Europe
Abstract
Partitioning of the available energy at the Earth's surface into the latent heat (LE) and sensible heat (H) fluxes has important climatological, hydrological, and physiological implications. With the prediction of more frequent droughts in central Europe in the near future, there is a particular need to understand variability in available energy partitioning under drought stress conditions at forest ecosystems that are common in the region, such as Norway spruce and European beech. Using eddy covariance measurements from two Norway spruce sites with contrasting wet and dry climates and one European beech site in the Czech Republic, it was found that the proportion of energy partitioned into H was greater at the spruce sites than at the beech site in all conditions during the growing season. The difference between the mean midday (09:00-15:00) β values for low stress conditions and drought stress conditions was much smaller at the European beech site (β = 1.04 vs. 1.11) than at the wet (β = 1.52 vs. 2.50) and dry Norway spruce (β = 1.80 vs. 2.70) sites, indicating that β was not as sensitive to drought stress at the European beech site as at the Norway spruce sites. The high β values and enhancement of drought conditions through positive feedback processes at Norway spruce stands mean that the potential substitution of Norway spruce monocultures with mixed broadleaf-coniferous stands in central Europe will likely lessen the severity of droughts and heat waves in the region.
- Publication:
-
Journal of Geophysical Research (Atmospheres)
- Pub Date:
- April 2019
- DOI:
- 10.1029/2018JD029490
- Bibcode:
- 2019JGRD..124.3726M
- Keywords:
-
- Bowen ratio;
- eddy covariance;
- Priestley-Taylor coefficient;
- stress;
- surface conductance