For more information:

http://www.eubon.eu/news

Larix sibirica covered in snow_Satakunta Experiment; Finland.

We are looking back to a successful field season, were we kept true to our philosophy: All measurements on all plots (-> picture gallery from this summer).

To make this happen, required a tremendous amount of km travelled. Some of our PhD students hardly spend a week at home this summer. A lot of discipline and long working hours in the field by PhD-students, site technicians, student helpers …..

But the work is far from done: currently our labs smell of dried leaves and soil. Leaves from litter traps are getting sorted into the different fractions. Roots samples need to be picked and separated. Soil is dried, milled and analysed.

Sorting leave litter for T3.7 in Satakunta, Finland

Technician Kris Ceunen (UGent) and M.sc. student Astrid Vannoppen (KU Leuven) processing soil samples in order to determine the functional diversity and biomass of the microorganism populations of the exploratory plots.

Charlotte Grossiord from INRA-Nancy is doing her PhD on Water balance, water use efficiency of trees (T3.9). This summer she was involved in fresh leave sampling and talking tree cores for isotope analysis. “So far we have been grinding and weighting the leaves we collected this summer in Italy, Germany and Finland. We even completed all analyses with an IRMS for δ¹³C and δ¹⁸O.

Concerning the wood cores that we took on all Exploratory sites, we are still separating the years of interest on the wood cores, grinding and weighting them in order to make the same analyses with the IRMS as for the leaves. For now Finland and Italy have been completely analyzed and we are currently working on the German cores.”

Virginie Guyot from INRA – Toulouse travelled three countries this year (Italy, Germany and Finland) to collect fresh leaves to study impact of forest diversity on herbivory insects and their natural enemies. “In total, at the end of summer, I (and many helpers) assessed the crown of 818 mature trees. We harvested about 43 000 leaves and shoots and we beated 623 saplings or low branches to collect spiders.

During autumn and winter, I have to assess the leaves and shoots collected. For the moment, I worked only on Castanea sativa from Italy and I start to analyse data. This specie is attacked by cynips which cause galls on burgeons and leaves (fig. 1). Figure 2 shows damage by other guilds of insects.”

Figure 1 : Leaves and burgeons attacked by Dryocosmus kuriphilus, an invasive cynips which induce galls on Castanea sativa, collected in Italy.

Figure 2 : Damages of different insect guilds on Castanea sativa leaves. A : Chewer – B&D : Tiers (silks are visible) – C : Roller – E&F : Miners – G : multiple damages on leaf (left to the right) : Chewer with caterpillar, Galler and Miner.

Diem Ngyuen and the team from SLU, Uppsala, Sweden have sampled the same trees as Virginie to assess fungal pathogens. Specifically they account for leaf spots, powdery mildew, rust and needle cast. Efforts are being focused on processing spruce needles from Germany and Finland from this very productive summer and preparing them for 454 pyrosequencing. A subset of spruce needles from last year´s sampling campaign in the Experimental Platform have been processed and sequenced. The fungal species from these samples comprise both endophytes and pathogens. The remainder of those needle samples are currently in South Korea being sequenced as we speak. The results from these two sequencing runs will guide how we proceed to obtain the best quality data from the samples in the exploratory plots that are currently stored in the many plastic boxes at SLU.

Rust caused by Chrysomyxa ledi on Norway spruce in Finland

Beneficial organisms for pest regulation are assess by Yohan Charbonnier, PhD student from INRA, Bordeaux, France. His winter work comprises of analysing sonograms from bat and birds recorded during this summer.

Pipistrellus pipistrellus

Above: Sonogram and audio file of Pipistrellus pipistrellus. In the first part of this file you will listen to the flying call, emitted for minimal informations (where are trees…) and eventually to detect prey.
In the middle there is an acceleration of rythms when the bat detects prey and tries to catch it. After the prey capture attempt the rythm will become slower.

To integrate information from this project with other efforts aimed at developing more stable and adaptable forest ecosystems for the future, a common workshop will be held together with the MOTIVE and the BACCARA project. MOTIVE aims to develop models for adaptive forest management. BACCARA has the main goal to develop tools to evaluate risks of European forest biodiversity and productivity loss under climate change.

A second workshop will combine science and forest management to explore additional silvicultural options to implement tree species diversity as an element of adaptation strategies.

Only recently a US study was published, which brought together scientific experts and forestry managers to ascertain some general adaptation strategies for the future, proving how fruitful such a discussion can be.

For more information:  Informing climate change adaptation in forestry management

Small wonder May Cherief has to think of this novel by Italo Calvino while watching the tree climbers fast ascend up a 40 m tall ash trees, swaying in the wind.  While the climbers adjust their short safety lines and ascend still further into the crowns of the tree to reach for the sunlight part of the crown, Virginie Guyot and May Cherief start to collect spiders from the shorter trees in the understorey. Virginie is a PhD-student from INRA, Bordeaux. Within FunDivEUROPE she will study the effect of tree diversity on resistance of trees to herbivores. Preliminary results from the Experimental Platform and the Baccara project suggest that the relationship between biodiversity and herbivore attacks is not as straight forward as commonly believed. The common believe that insect herbivory will decrease with increasing biodiversity could be confirmed for insects specialised on a specific species but not for generalists.  By collecting arthropods along the diversity gradient of the Exploratory Platform, Virginie extents her studies from herbivores to their predators.

“Watch out! Top branch down!” the first climber cuts a branch, and now we go and separate the leaves for the different research teams.

Diem Nguyen (SLU) and Virginie Guyot need leaves for herbivore and pathogen assessment. An additional sample for Diem will go straight to the drying oven, as they will be needed for DNA analysis of pathogens.

Charlotte Grossiord (INRA, Nancy) will use the leaves for isotope analysis of δ13C and δ18O, these provide time-integrated information on transpiration and water use efficiency. A week prior to this campaign she and other members of task 3.9 were installing sap-flow sensors within the highly instrumented plots (HIPs) for direct measures of transpiration (xylem flow) and predawn leaf water potential.

Nitrogen content of the leaves will also be determined for assessing nitrogen resorption efficiency by senescent leaves (task 3.6). The senescent leaves will be collected with litter traps during leaf fall.

Martina Pollastrini (UFI) and Vera Holland (GUF) place their leaves in black plastic bags. They need to be dark adapted for the measurement of photosynthetic acclimation with fluorescence of chlorophyll (JIP-test). Their research aim is to explore the possibility to use fluorescence as predictor of biomass productivity and resilience of the ecosystem.

While we take the leaves from the cut down branch and sort them to different bags, more and more branches start coming down from the trees. About two hours later tree climbers have been to 9 different trees in this three species mixture. Then it is time to come down from the tops, pack and walk to the next plot. In some case this means walking half an hour through the forest with 50 kg on your back. Life is so much nicer when you´re the baron in the trees.

Scientific teams and Tasks involved:

• T.3.4 Leaf area index (LAI) and photosynthesis parameters: Filippo Bussotti (UFI), Martina Pollastrini (UFI) and Vera Holland (GUF)
• T.3.6 Nitrogen ecophysiology of trees: Kalliopi Radoglou (NAGREF), Mariangela Fotelli (NAGREF), and Elefteria Dalmaris (NAGREF)
• T.3.9 Water balance and water use efficiency on different scales: Arthur Gessler (ALU-FR,), André Granier (INRA, Nancy) Damien Bonal (INRA, Nancy), Charlotte Grossiord (INRA, Nancy).
• T.4.3 Resistance to Insect Herbivores: Hervé Jactel (INRA, Bordeaux), Virginie Guyot (INRA, Bordeaux)
• T.4.6 Resistance to Fungal Pathogens: Helge Bruelheide (MLU), Jan Stenlid (SLU), Diem Nguyen (SLU).

Tree climbers and local site teams:

Italy:
Andrea Coppi – site technitian
Filippo Bussotti, Federico Selvi – site managers
Cinzia Sarti – arborist
Claudio Santelli – arborist
Giovanni Lotti – arborist
Francesco Ierimonti – arborist

Germany:
Felix Berthold – site technician
Helge Bruelheide – site manager
Carsten Beinhoff – site technician and arborist
Jessica Chudzinski – arborist
Bennet Mohr – arborist
Holger Sturhan – arborist
Andre Bernhard – arborist
Henrik Vollbrecht – arborist
Peter Vierveijzer – arborist

Finland:
Timo Domisch and Lena Finer – site managers

The team is currently in Finland and will return home afterwards. The Exploratory Regions of Spain, Romania and Poland will be visited next year.