Field Experiments & Instrumentation / Workshops                    --- Making Things Happen ---     



Reforestation area

Plots with differing tree species diversity

Latitude 50.77
Longitude 10.22
Elevation 328 m a.s.l.


  • From 2003 to present
  • Competition experiment
  • Tree growth
  • Wood increment
  • Meteorology



University of Freiburg - Prof. Dr. Michael Scherer-Lorenzen Description, History

Kaltenborn near Bad Salzungen is one of the three locations of the research project BIOTREE.

An area of 20 ha, which was a former military training ground, was divided in 16 parcels of woodland and afforested - "the Research forest of tomorrow".

The parcels of woodland are afforested with domestic/ indigenous tree species in different mixtures and number of species. There are parcels with only one Tree species (Reinbestand), but also plots with 2, 3, 4 up to 8 tree species. In these parcels every tree species is planted in group by 8 x 8 m.

Additional a part of the area is used for an experiment, where all tree species are mixed planted, so they all have different neighbors, to investigate competition of each against the other. Dominant species could surpress or surpass all other tree species in certain tree species mixtures.

Tree growth and wood increment are measured regularly, but also parameters like leaching of nutrients or groundwater recharge rate are determined.

Tree species: Picea abies (Spruce), Pseudotsuga menziesii (Douglas fir), Quercus petraea (Sessile oak), Fagus sylvatica (Beech) ) and as additional species Abies alba (European silver fir), Fraxinus excelsior (Common ash), Acer pseudoplatanus (Sycamore) und Sorbus aucuparia (Rowan).

By the time of planting, during the winter of 2003/2004 the seedlings were 3–4 years old and 20–60 cm high.

The project is financed by DEGES and Max-Planck-Institut for Biogeochemistry - responsibility lies today by
Prof. M Scherer-Lorenzen, University Freiburg,

The meteorological station was installed in November 2003 by the Field Experiments and Instrumentations Group.

Variables & Instruments


  • Wind velocity - cup anemometer A100R, Thies
  • Air temperature and humidity - temperature-humidity-sensor KPC1_5-ME, Mela
  • Precipitation - heated tipping bucket rain gauge, Thies
  • Solar radiation - pyranometer CM3, Kipp & Zonen

Soil conditions

  • Soil temperature - soil temperature sensors PT100, home-made
  • Soil moisture in 5 depths - soil moisture probes ML-2x, Delta-T

Data acquisition

  • Meteorological data - datalogger CR10X, Campbell Scientific


Ampoorter, E., Baeten, L., Vanhellemont, M., et al.(2015). Disentangling tree species identity and richness effects on the herb layer: first results from a German tree diversity experiment. Journal of Vegetation Science, 26(4), 742–755. Doi: 10.1111/jvs.1228

Scherer-Lorenzen, M., Schulze, E. D., Don, A., Schumacher, J., Weller, E. (2007). Exploring the functional significance of forest diversity: A new long-term experiment with temperate tree species (BIOTREE). Perspectives in Plant Ecology, Evolution and Systematics, 9(2), 53-70. Doi:10.1016/j.ppees.2007.08.002