Friday, January 2, 2015

GFZ Dendrochronology Laboratory

Dendrochronology Laboratory at the Helmholtz-Centre Potsdam – Deutsches GeoForschungsZentrum (German Research Center for Geosciences) is also known as the GFZ Dendrochronology Laboratory (for a shortened name) and is part of the Helmholtz-Centre Potsdam - GFZ (GeoForschungsZentrum) is the German Research Centre for Geosciences ( 

The Helmholtz Center Potsdam is part of the German Research Center for Geosciences which is a research facility that includes many different paleo techniques (including research on varved sediments and speleothems as well as dendrochronology for paleo records) as well as research in satellites, remote sensing, physics of the Earth, Geodynamics and Geomaterials, Chemistry and Material Cycles, and Earth Surface Processes including modelling. The dendrochronology lab is led by Dr. Gerd Helle and was the host to Dr. Ingo Heinrich and Dr. Sonia Simard as post-docs during my visit to the lab. Heiko Baschek is a full time technician and Franziska Slotta and Hagen Pieper are PhD students. The lab hosts many visiting researchers and students every year. Because this is a research institute, it does not offer graduate degrees so graduate students formally conduct their studies at other institutions such as University of Potsdam or Free University in Berlin. 

I was amazed at the level of instrumentation that they have in Potsdam. They have access to a wood shop and machine shop where wood can be surfaced or mechanisms can be constructed.

They have developed a larger increment borer bit for taking samples for stable isotope work that has a chisel cutting tip to cut and drill its way into the tree. 

Dr. Neil Loader at Swansea University designed an increment borer extractor for when you get your increment borer stuck in a tree. This is an ingenious little tool that has a reverse threaded shaft on a drill chuck. You can tighten the drill chuck on the increment borer and turn the increment borer handle to back out the borer and the reverse threads pull the borer from the tree.

They have two of Dr. Holger Gartner’s microtome’s for surfacing wood and making wood anatomy sections in a sample preparation laboratory located next to the instrument room with the mass spectrometers. 

In a dedicated measuring room, they have one each of the Lintab and Aniol measuring stations as well as a scanner with seven WinDendro licenses. They use the TSAP software by Rinntech (see the University of Innsbruck post for more details on this software) for crossdating.

They have another room where the students conduct most of their work with the Confocal Laser Microscope and Laser-Micro Dissection Microscope. In this picture from right (back) to left are Franziska Slotta, Dr. Gerd Helle, and Giuliano Locosselli.

They have a confocal laser scanning microscope that can make incredible images of whole cores at very high resolution. This technology along with good sample preparation from Dr. Gartner’s core microtomes, may be one route to increasing the speed of wood anatomical analysis of tree rings and was used by Wei Liang in her dissertation and recent publication (Liang et al. 2013, Liang 2014).

They have a UV-Laser-Microdissection (LMD) microscope (shown here being operated by Franziska Slotta) that enables them to cut specific areas of rings from their samples that then drop into tungsten crucibles to later be incinerated for stable isotope sampling. This instrument is used and described in Karina Schollaen’s papers and dissertation (Schollaen et al. 2013, Schollaen 2014, Schollaen et al. 2014).

One benefit from this process is that specific cells or areas of a ring can be cut for sampling. The samples are combusted within a closed vessel and an aliquot of gas is sampled and sent to the mass spectrometer so that one could conduct repeat sampling on the same piece of wood and no weighing of samples is necessary. 

They have three mass spectrometers connected to thermal resonance ovens that convert carbon to carbon monoxide for analysis.

They have a wood storage facility in a different building for larger sections and bulky sample collections.

Dr. Gerd Helle specialized in stable isotopic analysis of samples with research areas in Europe, Kirgizstan, South Africa, New Zealand, and the Tibetan Plateau (Helle et al. 2002, Helle and Schleser 2003, Helle and Schleser 2004a, Helle and Schleser 2004b). The GFZ Dendrochronology Laboratory has been developing stable isotope tree-ring networks throughout Eurasia.

Dr. Ingo Heinrich has explored the dendrochronological potential of a number of different tree species in Australia (Heinrich and Banks 2005, Heinrich and Banks 2006, Heinrich et al. 2009) and has worked on dendrogeomorphic dating of mass movements and wood anatomy in Europe (Heinrich and Gartner 2008, Heinrich et al. 2007).

Dr. Sonia Simard has worked on insect outbreak chronologies from stable isotopes (Simard et al. 2008, Simard et al. 2012) and in subfossil wood (Simard et al. 2011). She has examined carbohydrates in conifer trees (Simard et al. 2013) and examines cambial and apical meristem growth to better understand the development of tree-rings and how they record the environment (Rossi et al. 2009).

Franziska Slotta is conducting stable isotope and tree-ring research in Boabab trees in Botswana and South Africa to determine ring development through time and what can be discerned from its environmental response (Slotta et al. 2014a, Slotta et al. 2014b).

Hagen Pieper is a student at the GFZ Dendrochronology Lab and is working on stable isotopes is Lateglacial Central European tree rings (Pieper et al. 2014) and the effects of volcanic eruptions on tree growth over the last millennium in Germany (Pieper et al. 2013).

This location was originally part of the Prussian semaphore system which was a telegraphic communication system that was used between Berlin and the Rhine Province from 1832 to 1849. It used a series of optical patterns of slats and worked in conjunction with 62 other stations that could transmit signals 555km (340 miles). This structure still stands and is located outside of lodging for artists in residence which made me think that the structure was a sculpture initially. It sounded like the GFZ has a nice artist in residence program that supports writers, painters, and photographers to come and interact with the facilities and scientists here.

Einsteinturm (The Einstein Tower) is an astrophysical solar observatory that was designed by the astronomer Erwin Finlay-Freundlich, built by Erich Mendelsohn, and became operational in 1924. This observatory was built to test some of Einstein’s theories of relativity and to specifically look for gravitational lensing around the sun. Einstein was not directly involved with the research, but visited the observatory a few times. It is still a functioning solar telescope today that is operated by the Leibniz Institute for Astrophysics – Potsdam.

The architecture of the building is unique for the time by using curved surfaces.  It was originally supposed to be built from recently developed concrete, but because those materials were needed for other efforts, it was partly constructed from brick and covered with mesh and a plaster material.  Because of the different moisture holding content of the brick and the plaster, they actually had to repair cracks in the outer structure of the building within its first year.

The geophysical and remote sensing group developed the satellite CHAMP which was used to measure the gravitational anomalies around the globe.

They produced a three dimensional model of the globe based on these gravitational anomalies which is known colloquially as the Potsdam Potato. I was particularly fascinated with this model because it is a good representation of the continental and oceanic plate around the globe and has much bearing on the structural geology class that I teach.

Heinrich, I., & Banks, J. C. G. (2005). Dendroclimatological potential of the Australian red cedar. Australian Journal of Botany, 53(1): 21-32.
Heinrich, I., & Banks, J. C. (2006). Variation in phenology, growth, and wood anatomy of Toona sinensis and Toona ciliata in relation to different environmental conditions. International Journal of Plant Sciences, 167(4): 831-841.
Heinrich, I., & Gärtner, H. (2008). Variations in Tension Wood of Two Broad‐Leaved Tree Species in Response to Different Mechanical Treatments: Implications for Dendrochronology and Mass Movement Studies. International Journal of Plant Sciences, 169(7): 928-936.
Heinrich, I., Gartner, H., & Monbaron, M. (2007). Tension wood formed in Fagus sylvatica and Alnus glutinosa after simulated mass movement events. IAWA journal, 28(1): 39.
Heinrich, I., Weidner, K., Helle, G., Vos, H., Lindesay, J., & Banks, J. C. (2009). Interdecadal modulation of the relationship between ENSO, IPO and precipitation: insights from tree rings in Australia. Climate dynamics, 33(1): 63-73.
Helle, G., & Schleser, G. H. (2003). Seasonal variations of stable carbon isotopes from tree-rings of Quercus petraea. TRACE: Tree Rings in Archaeology, Climatology and Ecology, 1: 66-70.
Helle, G., & Schleser, G. H. (2004). Interpreting climate proxies from tree-rings. In The Climate in Historical Times Springer Berlin Heidelberg: 129-148.
Helle, G., & Schleser, G. H. (2004). Beyond CO2‐fixation by Rubisco–an interpretation of 13C/12C variations in tree rings from novel intra‐seasonal studies on broad‐leaf trees. Plant, Cell & Environment, 27(3): 367-380.
Helle, G., Schleser, G. H., & Braeuning, A. (2002). Climate history of the Tibetan Plateau for the last 1500 years as inferred from stable carbon isotopes in tree-rings. Proceedings of the study of environmental change using isotope techniques, International Atomic Energy Agency (IAEA) conference: 301-311.
Liang, W. 2014. Growth response of Scots pine to climate variability derived from quantitative wood anatomy. PhD Dissertation submitted to the University of Potsdam.
Liang, W., Heinrich, I., Helle, G., Liñán, I. D., & Heinken, T. (2013). Applying CLSM to increment core surfaces for histometric analyses: A novel advance in quantitative wood anatomy. Dendrochronologia, 31(2): 140-145.
Pieper, H., Brauer, A., Miramont, C., Nievergelt, D., Büntgen, U., & Helle, G. (2014, May). Annually resolved stable isotope chronologies from Lateglacial Central European tree rings. In EGU General Assembly Conference Abstracts (Vol. 16, p. 883).
Pieper, H., Heinrich, I., Heußner, K. U., & Helle, G. (2013, April). The influence of volcanic eruptions on growth of central European lowland trees in NE-Germany during the last Millennium. In EGU General Assembly Conference Abstracts (Vol. 15, p. 1013).
Rossi, S., Simard, S., Rathgeber, C. B., Deslauriers, A., & De Zan, C. (2009). Effects of a 20-day-long dry period on cambial and apical meristem growth in Abies balsamea seedlings. Trees, 23(1): 85-93.
Schollaen, K. 2014. Tracking climate signals in tropical trees: New insights from Indonesian stable Isotope records. PhD Dissertation submitted to University of Potsdam.
Schollaen, K., Heinrich, I., & Helle, G. (2014). UV‐laser‐based microscopic dissection of tree rings–a novel sampling tool for δ13C and δ18O studies. New Phytologist, 201(3): 1045-1055.
Schollaen, K., Heinrich, I., Neuwirth, B., Krusic, P. J., D’Arrigo, R. D., Karyanto, O., & Helle, G. (2013). Multiple tree-ring chronologies (ring width, d 13 C and d 18 O) reveal dry and rainy season signals of rainfall in Indonesia. Quaternary Science Reviews, 73(17): 0e181.
Simard, S., Elhani, S., Morin, H., Krause, C., & Cherubini, P. (2008). Carbon and oxygen stable isotopes from tree-rings to identify spruce budworm outbreaks in the boreal forest of Québec. Chemical Geology, 252(1): 80-87.
Simard, S., Morin, H., & Krause, C. (2011). Long‐term spruce budworm outbreak dynamics reconstructed from subfossil trees. Journal of Quaternary Science, 26(7): 734-738.
Simard, S., Morin, H., Krause, C., Buhay, W. M., & Treydte, K. (2012). Tree-ring widths and isotopes of artificially defoliated balsam firs: A simulation of spruce budworm outbreaks in Eastern Canada. Environmental and Experimental Botany, 81: 44-54.
Simard, S., Giovannelli, A., Treydte, K., Traversi, M. L., King, G. M., Frank, D., & Fonti, P. (2013). Intra-annual dynamics of non-structural carbohydrates in the cambium of mature conifer trees reflects radial growth demands. Tree physiology, 33(9): 913-923.
Slotta, F., Helle, G., Heußner, U., Woodborne, S., Riedel, F. (2014a): Dendro-ecophysiology of baobabs: Towards a better understanding via dendrometer and stable isotope studies, TRACE 2014 - Tree Rings in Archaeology, Climatology and Ecology (Aviemore, Scotland 2014).

Slotta, F., Riedel, F., Heußner, K.-U., Helle, G. (2014b): The African Baobab - a high-resolution archive for climate variability of semi-arid Africa? - Conference Program Book, 9th International Conference on Dendroclimatology (Melbourne 2014) (Melbourne, Australia 2014), p. 107.

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