July 2022

Estimating germination rates: continuation of the climate chamber experiment with new provenances

Our student Mert Celik continued the climate chamber experiment started by Johannes Alt (see below results from April 2022) and finished testing all provenances used for the trials 2021-2026. This includes provenances of Abies alba, Abies nordmanniana, Fagus sylvatica and Fagus orientalis.

Using the same dark-light cycle (16 h dark, 8 h light), this time the experiment was maintained for 16 weeks to see if germination rates reached a plateau. Ambient temperature was kept at 5-15 oC for the first nine weeks, and it was increased to 10-20 oC for the rest of the experiment duration. For all species and provenances, germination rates reached the plateau in 80 to 85 days after the beginning of the experiment.

Once concluded, Mert combined the results of the first and the second experiment and showed that germination rates of the species belonging to the Abies genus ranged between 9% and 65% with a mean germination rate of 33%. Caucasian fir (Abies nordmanniana) outperformed all other silver fir provenances with a germination rate of 65%. In the Fagus genus, the oriental beech from the Iranian Alborz Mountains reached the highest germination rate of 72%. Across provenances, germination rates ranged between 0% and 72%, with a mean rate of 29%. Beech from Romania (SE Carpathians) and Switzerland (Salenstein) did not germinate at all during the experiment.

These results partly reflect what is happening in the micro-gardens in the field (check the preliminary results in the section below!).

Germination curves obtained from the germination data for silver fir and caucasian fir (top graph), and European and oriental beech (bottom graph); dotted lines indicate moist treatments, solid lines indicate dry treatment.

June 2022

Germination descriptive results

Depending on the chosen variable, you can explore :

  • the percentage of germinated seeds in each garden ("Micro-garden")

  • the number of germinated seeds for each germination stage ("Germination stage")

  • the percentage of germinated seeds for each provenance ("Provenances-Abies" or "Provenances-Fagus")

  • the evolution of the percentage of germinated seeds in each garden ("Evolution-Abies" or "Evolution"Fagus")

  • the number of germinated seeds for each provenance and in each garden ("Heatmap-Abies" or "Heatmap-Fagus")

April 2022

Estimating germination rates using a climate chamber experiment

Master thesis by Johannes Alt

Part of the seeds provenances used in the trials 2021-2026, have been tested in our climate chamber at WSL by master student Johannes Alt. Johannes' objective was to assess the germination rate of the provenances under a dry and moist water regime. The germination test was done in a climate chamber using a cycle of 16h night and 8h day at 5 – 15°C for eight weeks and 10 – 20°C for additional two weeks.

European beech reached a mean germination rate of 38.2% (ranging from 29% to 59% between provenances) while for silver fir it was 25.4% (9% to 39%). The different water regimes had no significant effect on the germination rate. Nevertheless, for both European beech and silver fir Johannes found a significant provenance effect on the germination rate, indicating that not all origins are equally suitable for the conditions tested.

The second germination experiment with the rest of the provenances is currently ongoing. The combined results from all provenances will provide a solid baseline for comparison with germination in the micro-gardens. This will help us generate information on the suitability of the different provenances and their potential for assisted migration!

Germination curves obtained from the germination data for silver fir (A), and European beech (C); dotted line indicates higher temperature cycle (10-20°C); line defines the end of the experiment; day 72 equals absolute germination rate

November 2021

Summer trials 2021

The very first trials of MyGardenOfTrees!

Enthusiastic citizens and NGOs from Scotland, France, Italy, Switzerland and Hungary helped us develop different steps of the project. Together, we tested the first version of the experimental design and particularly the effect of seed predation by rodents (using mesh cages) and competition (using weed exclusion sheets).

While competition from other seedlings seemed not to have a strong effect, seeds and seedlings predation from mice and snails was a clear issue. Because of these results, we designed a new kind of seed protector that we used for the following trials.

Citizen science is a beautiful way to do research which benefits both the scientific community and the public. Thanks to our early participants, we could go through the different steps of engaging and working with citizens and prepare us for the large-scale participation of the next trials!

Check out this great video from our participants in Scotland to learn more about the summer trials 2021!