BIOTREE (Germany)

The BIOTREE experiment in Thuringia (Bechstedt, Kaltenborn, Mehrstedt) has been established in 2003/2004 and consists of three subexperiments: BIOTREE-SPECIES, focusing on species richness effects BIOTREE-FD, focusing on functional diversity effects, and BIOTREE-SIMPLEX, focusing on the effects of evenness on ecosystem functioning. Replicate forest communities were created based on the pool of local tree species and one exotic species. The main goals of the experiments are (1) quantifying the effects of tree diversity on key ecosystem processes, e.g., tree growth, long-term C sequestration, nutrient cycling, and structural characteristics, and (2) understanding the mechanisms of BDEF relationships and how forest management can influence them or ensure both economic and ecological sustainability.

aerial view of the BIOTREE-FD experiment
Aerial view of the BIOTREE-FD experiment in Bechstedt (June 2012)


A diversity gradient was established by manipulating the number of species per plot. Each plot was subdivided in three subplots to accommodate a management treatment: (1) no management, (2) thinning according to close-to-nature forestry, and (3) thinning in plots in which 4 additional species adjusted to the site were planted. Trees were planted in monospecific cells of 8 m x 8 m. These cells were randomly distributed within a subplot, and this distribution was repeated in the two other subplots of the plot. Within a cell, the trees were planted on rows that were 2 m apart. The within-row distance between trees depends on the planted species. The subexperiment consists of two sites: Mehrsted (calcareous soil, 1-6 species per plot) and Kaltenborn (acidic soil, 1-4 species per plot).

BIOTREE-SPECIES plots in Mehrstedt BIOTREE-SPECIES plots in Kaltenborn
The plots of BIOTREE-SPECIES at the Mehrsted and Kaltenborn sites
and the within-plot design of a 4-species plot at the two sites

The BIOTREE-FD experiment has a gradient of tree functional diversity, at a constant number of tree species. All 25 plots contain 4 tree species, taken out of a total species pool of 16 species. The functional diversity of the plots - based on leaf type, light requirement, mean annual increment and litter C/N ratio - varies between very low and very high. Within each hexagonal plot, trees were planted in 44 monospecific round cells of 20 trees (planting distance 1 m x 2 m), i.e., 11 cells per tree species per plot.

BIOTREE-FD plots in Bechstedt BIOTREE-FD plot design
The plots and within-plot design of BIOTREE-FD in Bechstedt

In the BIOTREE-SIMPLEX experiment, a gradient of tree species evenness has been established, by using different abundances of four species. There are 36 plots in total, with three different evenness levels and two different densities, replicated twice. The evenness levels are (1) dominant (70:10:10:10), (2) co-dominant (30:30:30:10), and (3) even (25:25:25:25), with all possible abundance combinations of the four species. Planting distances in the low density treatment are 2 x 1.5m (80 individuals per plot), and 1 x 1.5m in the high density treatment (150 individuals per plot).

BIOTREE-SIMPLEX plots in two blocks BIOTREE-SIMPLEX plot design
The plots and within-plot design of BIOTREE-SIMPLEX in Kaltenborn.
An example of a high-density, co-dominant mixture is shown.

Site characteristics

location Mehrstedt Kaltenborn Bechstedt Kaltenborn
former land use grassland, then pasture cropland till 1975, then grassland pasture pasture
altitude 293 m 325 m 400 m 325 m
soil type Stagnic vertisols dominated by clay and silt on a limestone bedrock Orthoeutric arenosols with loamy sand on a sandstone bedrock Stagnic vertisols on a limestone bedrock Orthoeutric arenosols with loamy sand on a sandstone bedrock
area 40 ha 23 ha 11 ha 1.5 ha
no of plots 40 16 25 36
plot size 72 m x 144 m 48 m x 124 m 43.5 m x 56 m 16 m x 16 m
no of trees planted 137 612 31 096 22 000 4140
planting date spring 2003 spring 2004 spring 2003 spring 2004
diversity variables species richness species richness functional diversity species evenness
diversity gradient 1, 2, 4, 6 sp. 1, 2, 3, 4 sp. very low - very high low, mid, high
size species pool 10 8 16 4
species pool Main tree species: Acer pseudoplatanus, Fagus sylvatica, Larix decidua, Pseudotsuga menziessii, Quercus petraea, Tilia cordata
Additional tree species: Acer platanoides, Carpinus betulus, Fraxinus excelsior, Prunus avium
Main tree species: Fagus sylvatica, Picea abies, Pseudotsuga menziessii, Quercus petraea
Additional tree species: Abies alba, Acer pseudoplatanus, Fraxinus excelsior, Sorbus aucuparia
Acer campestre, A. platanoides, A. pseudoplatanus, Betula pendula, Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Larix decidua, Pinus sylvestris, Populus tremula, Prunus avium, Quercus pertraea, Sorbus aucuparia, S. torminalis, Tilia cordata, Ulmus glabra Fagus sylvatica, Picea abies, Pseudotsuga menziessii, Quercus petraea
contact persons Michael Scherer-Lorenzen, Charles Nock

Studies will focus on the relationship between tree species richness, functional diversity or tree species evenness and soil properties, tree growth and mortality, herb layer diversity and composition, herbivory damage, and carbon sequestration. Regular inventories for height and diameter growth, crown sizes and mortality have been done every three years. Additional data sampling was done within the EU-projects BACCARA and FunDivEUROPE.

Extra information
Send an e-mail to the contact persons, visit the experiment's own website, or explore the publications:

  • Annighöfer P, Ameztegui A, Ammer C, Balandier P, Bartzsch N, Bolte A, Coll L, Collet C, Ewald J, Frischbier N, Gebereyesus T, Haase J, Hamm T, Hirschfelder B, Huth F, Kändler G, Kahl A, Kawaletz H, Kuehne C, Lacointe A, Lin N, Löf M, Malagoli P, Marquier A, Müller, Promberger S, Provendier D, Röhle H, Sathornkich J, Schall P, Scherer-Lorenzen M, Schröder J, Seele C, Weidig J, Wirth C, Wolf H, Wollmerstädt J, Mund M (2016) Species-specific and generic biomass equations for seedlings and saplings of European tree species. European Journal of Forest Research 135: 313-329 - doi: 10.1007/s10342-016-0937-z
  • Verheyen K, Vanhellemont M, Auge H, Baeten L, Baraloto C, Barsoum N, Bilodeau-Gauthier S, Bruelheide H, Castagneyrol B, Godbold D, Haase J, Hector A, Jactel H, Koricheva J, Loreau M, Mereu S, Messier C, Muys B, Nolet P, Paquette A, Parker J, Perring M, Ponette Q, Potvin C, Reich P, Smith A, Weih M, Scherer-Lorenzen M (2016) Contributions of a global network of tree diversity experiments to sustainable forest plantations. Ambio 45: 29-41 - doi: 10.1007/s13280-015-0685-1
  • Ampoorter E, Baeten L, Vanhellemont M, Bruelheide H, Scherer-Lorenzen M, Baasch A, Erfmeier A, Hock M, Verheyen K (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: 742-755 - doi: 10.1111/jvs.12281
  • Domisch T, Finér L, Dawud SM, Vesterdal L, Raulund-Rasmussen K (2015) Does species richness affect fine root biomass and production in young forest plantations? Oecologia 177: 581-594 - doi: 10.1007/s00442-014-3107-3
  • Haase J, Castagneyrol B, Cornelissen JHC, Ghazoul J, Kattge J, Koricheva J, Scherer-Lorenzen M, Morath S, Jactel H (2015) Contrasting effects of tree diversity on young tree growth and resistance to insect herbivores across three biodiversity experiments. Oikos 124: 1674-1685 - doi: 10.1111/oik.02090
  • Paine CET, Amissah L, Auge H, Baraloto C, Baruffol M, Bourland N, Bruelheide H, Daïnou K, de Gouvenain RC, Doucet J-L, Doust S, Fine PVA, Fortunel C, Haase J, Holl KD, Jactel H, Li X, Kitajima K, Koricheva J, Martínez-Garza C, Messier C, Paquette A, Philipson C, Piotto D, Poorter L, Posada JM, Potvin C, Rainio K, Russo SE, Ruiz-Jaen M, Scherer-Lorenzen M, Webb CO, Wright SJ, Zahawi RA, Hector A (2015) Globally, functional traits are weak predictors of juvenile tree growth, and we do not know why. Journal of Ecology 103: 978-989 - doi: 10.1111/1365-2745.12401
  • Schwarz B, Dietrich C, Cesarz S, Scherer-Lorenzen M, Auge H, Schulz E, Eisenhauer N (2015) Non-significant tree diversity but significant identity effects on earthworm communities in three tree diversity experiments. European Journal of Soil Biology 67: 17-26 - doi: 0.1016/j.ejsobi.2015.01.001
  • Grossiord C, Gessler A, Granier A, Berger S, Bréchet C, Hentschel R, Hommel R, Scherer-Lorenzen M, Bonal D (2014) Impact of interspecific interactions on the soil water uptake depth in a young temperate mixed species plantation. Journal of Hydrology 519: 3511-3519 - doi: 10.1016/j.jhydrol.2014.11.011
  • Hantsch L, Braun U, Haase J, Purschke O, Scherer-Lorenzen M, Bruelheide H (2014) No plant functional diversity effects on foliar fungal pathogens in experimental tree communities. Fungal Diversity 66: 139-151 - doi: 10.1007/s13225-013-0273-2
  • Pollastrini M, Holland V, Brüggemann W, Koricheva J, Jussila I, Scherer-Lorenzen M, Berger S, Bussotti F (2014) Interactions and competition processes among tree species in young experimental mixed forests, assessed with chlorophyll fluorescence and leaf morphology. Plant Biology 16: 323-331 - doi:10.1111/plb.12068
  • Grossiord C, Granier A, Gessler A, Scherer-Lorenzen M, Pollastrini M, Bonal D (2013) Application of Loreau & Hector's (2001) partitioning method to complex functional traits. Methods in Ecology and Evolution 4: 954-960 - doi: 10.1111/2041-210X.12090
  • Hantsch L (2013) Tree diversity effects on species richness and infestation of foliar fungal pathogens in European tree diversity experiments. PhD thesis, Martin-Luther University Halle
  • Hantsch L, Braun U, Scherer-Lorenzen M, Bruelheide H (2013) Species richness and species identity effects on occurrence of foliar fungal pathogens in a tree diversity experiment. Ecosphere 4: 81 - doi: 10.1890/ES13-00103.1
  • Morath S (2013) Effects of tree species diversity on insect herbviory. PhD thesis, Royal Holloway University of London
  • Lei P, Scherer-Lorenzen M, Bauhus J (2012) Belowground facilitation and competition in young tree species mixtures. Forest Ecology and Management 265: 191-200 - doi: 10.1016/j.foreco.2011.10.033
  • Lei P, Scherer-Lorenzen M, Bauhus J (2012) The effect of tree species diversity on fine-root production in a young temperate forest. Oecologia 169: 1105-1115 - doi: 10.1007/s00442-012-2259-2
  • Lei P, Bauhus J (2010) Use of near-infrared reflectance spectroscopy to predict species composition in tree fine-root mixtures. Plant and Soil 333: 93-103 - doi: 10.1007/s11104-010-0325-2
  • Don A, Rebmann C, Kolle O, Scherer-Lorenzen M, Schulze E-D (2009) Impact of afforestation-associated management changes on the carbon balance of grassland. Global Change Biology 15: 1990-2002 - doi: 10.1111/j.1365-2486.2009.01873.x
  • Don A (2007) Carbon dynamics of young experimental afforestations in Thuringia. PhD thesis, Eberhard Karls University Tübingen
  • 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: 53-70 - doi: 10.1016/j.ppees.2007.08.002

photo mixed plot photo mixed plot
Mixed plots at the BIOTREE-FD experiment in Bechstedt (May 2014)