ECOLINK-Salix (Sweden-Germany)


The three experimental field sites of ECOLINK-Salix have been established along a 1500 km latitudinal gradient, from Uppsala (Sweden) to Rostock and Freiburg (Germany), in spring 2014. The plantations are short rotation coppice stands. Shoot biomass was harvested for the first time after three years of growth (in winter 2016/2017). The overall goal of ECOLINK-Salix is assessing the effects of genotype identity and diversity in willow short rotation coppice on various ecosystem functions and, ultimately, tree growth and yield stability (e.g. resistance to drought and pests). Particular focus lies on functions that are important for ecological sustainability, such as water and nutrient use, carbon sequestration, and biodiversity.

aerial view of the sites
The location of the site in Uppsala, Rostock, and Freiburg


Design
The experiment has a randomized block design, with three replicates (blocks). Salix varieties, i.e., genotypes, with known characteristics and different taxonomic relationships (full siblings to different species) were planted in all theoretically possible combinations: plots with single varieties, mixtures of two, three, and four varieties. The diversity treatments were assigned randomly to plots within a block. Four Salix varieties were planted - from near to more remote taxonomic relationship:

  • 'Tora' (Svalöf-Weibull (SW) cultivar no. 910007, S. schwerinii × S. viminalis)
  • 'Björn' (SW 910006, Salix schwerinii E. Wolf. × S. viminalis L.)
  • 'Jorr' (SW 880013, S. viminalis)
  • 'Loden' (SW 890129, S. dasyclados)
All four varieties are grown in Uppsala and Freiburg; only 'Tora' and 'Loden' are grown at the Rostock site.



The blocks at Uppsala, Rostock, and Freiburg. A block in Uppsala or Freiburg contains 15 plots (1-4 varieties); a block in Rostock contains 3 plots (1-2 varieties). All plots are 9.6 m x 9.6 m large.


Hexagonal planting design in plots with one, two, and three varieties. In plots with three and four varieties, the position of varieties was randomized, but within columns and lines, each individual is directly neighboured by an individual of a different variety. Planting density was c. 15600 plants ha-1. Each plot contains nine subplots (3.2 m x 3.2 m, 16 plants), which will be used for specific assessments, e.g., litter decomposition, weed dynamics, soil biology.


Site characteristics

site Uppsala Rostock Freiburg
former land use arable arable grassland (sheep grazing)
altitude 12 m 13 m 230 m
soil type vertic cambisol stagnic cambisol cambisol
area 4147 m2 829 m2 4424 m2
no of plots 45 9 45
plot size 92.16 m2 92.16 m2 92.16 m2
no of trees planted 6480 1296 6480
planting date 2014 2014 2014
diversity variables genetic diversity genetic diversity genetic diversity
diversity gradient 1-4 varieties 1-2 varieties 1-4 varieties
size species pool 4 2 4
species pool Salix varieties:
Tora, Björn, Jorr, Loden
Salix varieties:
Tora, Loden
Salix varieties:
Tora, Björn, Jorr, Loden
contact person Martin Weih Christel Baum Michael Scherer-Lorenzen


Research
We will test the ecosystem consequences of adding individual genotypes of trees. We want to functionally and quantitatively explore how the heritable traits of some genotypes of Salix affect (1) ecosystem productivity, litter decomposition and soil carbon sequestration; (2) the abundance and structure of associated mycorrhiza communities; (3) the action of herbivorous insects; and (4) the diversity and function of understory vegetation. At individual sites, additional research questions will be conducted, e.g. on resource use complementarity, soil hydrology or wood quality. The research will have implications for future bio-energy concepts because new genotypes of energy crops such as Salix generated by plant breeding must comply with sustainability requirements, e.g., biodiversity and carbon sequestration, for a carbon-neutral and environmentally friendly energy source, e.g. Weih et al. (2014).



Extra information
Send an e-mail to the contact persons.

the Uppsala site in August 2014 the Rostock site in April 2014 the Freiburg site in October 2016
The Uppsala site (August 2014) during the first growing season, the Rostock site at the time of establishment (April 2014), and the Freiburg site after the third growing season (October 2016)


Funding
The ECOLINK-Salix project is currently funded by the Swedish Energy Agency (project no. 36654-11 and 36654-2) and the Swedish Research Council Formas (project no. 2016-00998). In addition, the trial in Freiburg is supported financially through the "Innovationsfonds Forschung" of the Freiburg University for the project "Mechanisms of tree diversity effects on ecosystem functioning, and through the "Forschungsprogramm Bioökonomie" of the state of Baden-Württemberg for the project "Hochdivers-KUP: Nutzung von Baum-Diversität zur Erhöhung der Produktivität und ökologischen Stabilität von Kurzumtriebsplantagen".