Prof. Katarina Čufar is the recipient of the 2021 Jesenko Lifetime Achievement Award (photo Željo Stevanović, IFP)
Publish Date: 06.04.2021
Category: Researchers in focus , Interdisciplinary research, Our contribution to sustainable development goals
Sustainable development goals: 13 Climate action, 15 Life on land (Indicators)
Prof. Katarina Čufar is the recipient of the 2021 Jesenko Lifetime Achievement Award, the most prestigious award given by the Biotechnical Faculty.
In 2020, she was also the recipient of the Gold Plaque of the University of Ljubljana and the Zois Award for important achievements.
Prof. Čufar and her colleagues study wood as tree tissue: “Growth rings can be several millimetres wide and consist of a large number of cells. By studying wood formation, we can determine how individual cells are formed and under what conditions, when the cambium is active and how it produces wood and bark. This is vital to ensure the survival of trees.”
The award is named after Prof. Fran Jesenko, the first Professor of Botany at the University of Ljubljana, an outstanding teacher and scientist who was aware of the importance of science and research for economic and social progress (photo Željo Stevanović, IFP)
Development of dendrochronology in Slovenia
Dendrochronology is a science that involves tree-ring analyses to date the annual growth rings and to define the exact year they were formed. This provides a starting point for many applications in archaeology, ecology and other fields (photo Katarina Čufar)
Prof. Čufar loves nature, so she decided to study and focus her research on wood science. Her diploma and master’s thesis investigated the anatomy and properties of tropical wood species: “The research was conducted as part of international projects that connected us with an international community. In my PhD, I focused on silver fir dieback and wood biology. We introduced dendrochronological methods into our research and found that wood formation may be completely absent in some years, leaving the tree to decline. After completing my PhD, I was very happy that restorers and archaeologists came with a proposal to systematically develop dendrochronology for the research of wood in cultural heritage.” Prof. Čufar and colleagues gladly accepted this challenge, assembled a team and started to develop dendrochronology in Slovenia.
Rural architecture and castles are an important part of Slovenia’s cultural heritage. Dendrochronology allows us to date wooden structures even when information from other sources is not available (photo Katarina Čufar)
Based on 20 years of research into archaeological wood remains from more than 15 pile-dwellings in the Ljubljansko Barje, we were able to determine precisely when the pile dwellers cut the wood down and how they used it, giving us an insight into their lifestyle and skills. These findings help us better understand events that took place in the distant past (author of the pictures above Katarina Čufar, picture below Anton Velušček)
Archaeological wood remains from the Ljubljansko Barje pile-dwellings
Tree-rings in the wood, provide a record of past climate conditions, as well as other factors affecting wood formation. Thanks to dendrochronology, we can date individual growth rings and determine what the weather conditions were like during the year they were formed. This also enables us to date wood in cultural heritage objects. Archaeological wood remains thus reveal the age of the pile-dwellings and the oldest wheel found in the world.
A team of researchers from the Institute of Archaeology at the Slovene Academy of Sciences and Arts and the Biotechnical Faculty was able to determine when the wood found at more than 15 pile-dwellings was cut down and how it was used to build the dwellings and produce various objects. The youngest wood remains are more than 4,400 years old. Dendrochronology and radiocarbon dating helped determine the age of the wooden wheel with an axle, which was found at the pile-dwelling site Stare Gmajne and is now kept at the City Museum of Ljubljana.
The 5,150-year-old wooden wheel is made of two radial planks of ash bound together by four dovetail grooves and tongues. The axle is made of oak. The wood has undergone significant changes over the millennia (photo Rado Likon)
The remains of an early Roman ship were discovered during preventive underwater archaeological research of the Ljubljanica riverbed near Sinja Gorica in 2008. The results of dendrochronological analysis show that the ship, made of beech, was built soon after the year 3 AD when the Romans conquered the area of the present-day central Slovenia. The ship is the first dendrochronologically dated wooden object from the Roman period in Slovenia and its wider region (photo Rok Kovačič and Katarina Čufar, 3D model: Gregor Berginc; processed with Mementify©PHOV; a 3D view in Meshlab).
Numerous Bachelor’s and Master’s students, outstanding PhD projects and cooperation with science postgraduates
Prof. Katarina Čufar is a dedicated teacher. She has mentored and co-mentored almost a hundred Bachelor’s and Master’s students, as well as PhD students whose theses have been internationally ground-breaking: “Working with young people enriches us, and I am proud to have been able to take part in their education, teaching them and learning from them. There have also been many opportunities recently to mentor young postdoctoral scientists from all over the world, which I was happy to accept.”
International cooperation and connections
“International cooperation, both in formal and informal project groups, is essential for creating new knowledge and new insights on a global scale,” says Prof. Čufar.
Research on wood anatomy and biology is today often linked with dendrochronology. “In addition to dendrochronology, which interprets the natural record of climate conditions preserved in wood structure, we have also developed dendroclimatology and dendroecology. We conducted dendroclimatological studies with international research groups that enabled us to reconstruct the climate in Slovenia and Europe over the past centuries and millennia. Climate affects the growth of trees, more so under the conditions of global climate change, so we are also advancing dendroecological studies,” Prof. Čufar explains.
Latest research: Growth ring widths enable a spatio-temporal assessment of beech growth in relation to extreme climate events in Slovenia
Extreme climate events resulting from climate change cause damage and physiological changes in forest trees. Changes in tree tissues can be closely investigated and evaluated through long-term observations and laboratory analyses. Remote sensing can also provide a broader picture at the level of tree populations.
Tree-ring analyses of beech wood and remote sensing helped to produce the map of deviations in Enhanced Vegetation Indices (EVI) and areal distribution of of trees damaged by ice strom in February 2014 with changes in the EVI during 2014 and in the period from 2001 to 2017 (photo Katarina Čufar and Matthieu Decuyper)
A recent study published in Agricultural and Forest Meteorology included beech trees from 25 sites in Slovenia. It demonstrated how tree-ring data and crown characteristics derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and EVI (Enhanced-Vegetation-Index) can be used to assess the effect of extreme climate events on the growth of beech. It was shown that extreme climate events (ice storms, frosts, heat waves) that occurred between 2001 and 2017 affected the EVI. The biggest changes in the EVI were related to the major ice storm in 2014, which caused significant damage to trees and a consequent decline in annual growth increments.
The EVI changes represented on the maps indicated the areas in Slovenia where beech is most sensitive to climate change. The findings allowed to upscale tree-based knowledge to a broader understanding of the processes at forest level, which is important for planning mitigation interventions.
Source: DECUYPER, M., CHÁVEZ, R.O., ČUFAR, K., ESTAY, S. A., CLEVERS, J.G.P.W., PRISLAN, P., GRIČAR, J., ČREPINŠEK, Z., MERELA, M., DE LUIS, M., NOTIVOLI, R.S., MARTINEZ DEL CASTILLO, E., ROZENDAAL, D.M.A., BONGERS, F., HEROLD, M., SASS-KLAASSEN, U., 2020. Spatio-temporal assessment of beech growth in relation to climate extremes in Slovenia – An integrated approach using remote sensing and tree-ring data. Agricultural and Forest Meteorology 287, 107925, 1-10, https://doi.org/10.1016/j.agrformet.2020.107925
A video presenting the work of Prof. Katarina Čufar, recipient of the 2021 Jesenko Lifetime Achievement Award