2022/04/09 by Thomas M. Hinckley, R. Ceulemans, Emil Cienciala +4 · 1 voice
Agricultural and Biological Sciences · Environmental Science · #Plant Stress Responses and Tolerance #Plant Water Relations and Carbon Dynamics #Plant responses to water stress
paper · pdf · doi:10.1093/treephys/tpac039
openalex publication_date 2022/04/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
One of the giants in Czechoslovakia – now the Czech Republic – in plant water relations, Professor Jan Čermák, passed away on December 23, 2021, in Brno, Czech Republic. Following in the footsteps of earlier noted Czech physiological ecologists – Jiří Čatský, Pavol Eliáš, Josef Huzulák, Zdeněk Šesták and Bohdan Slavík – Jan Čermák carved a reputation in plant water relations. Unlike the others, Čermák collaborated globally in his research endeavors, and these collaborations spanned almost four decades. Jan Čermák was born on July 23, 1938 in Prague, Czechoslovakia as the second son in the medical family of Doctor Václav Čermák. He grew up in Prague in an intellectually stimulating environment and his personality was strongly influenced by his years in scouting. For his entire life, he remained very fond of the capital city and of Central Bohemia. He started exploring nature as a high school student and was soon accepted in the Czech Ornithological Society, where he cooperated with the recording of observations of banded birds by the National Museum in Prague. In June 1957, he completed, with honors, high school in Říčany, a small town just southeast of Prague. Until September 1958, he worked as a forest laborer at the Jílové forest plant and two years later, in 1960, he graduated from the forest technical school in the town of Písek. He decided to enroll for Master studies in the Faculty of Forestry of the Agricultural University of Brno in 1960. Brno became his new, beloved hometown and he fully enjoyed the landscape, nature and forests of Moravia. In June 1965, he obtained a Master of Science degree with high distinction. After having completed his full-time military service in September 1966, he joined the Vlašim forestry enterprise as a forest engineer/silvicultural technician. Between 1966 and 1967, he completed two study stays, one at the Institute of Instrumental Analytical Chemistry of the Czechoslovakian Academy of Sciences in Brno and one at the Norwegian Forest Research Institute in Vollebekk. Subsequently, he became a research assistant (1967–1969) at the Institute of Forest Botany and Phytocenology, Forest Faculty of the Agricultural University of Brno. Shortly thereafter in 1971, while he was working at the Institute of Forest Botany and Phytocenology, the rector of the same university noticed him and offered him a position at the Institute of Forest Ecology, founded as part of the large international Man and Biosphere (MAB) project. The Czech participation in this project was canceled by the new government, but the Institute somehow survived. Early in his career Čermák studied volatile compounds and liquid fractions of terpenes, secondary metabolites released by trees for their defense and communication. This subject area formed the foundation for his dissertation. However, his research interest soon turned toward the measurement of water movement through stems and roots of trees as well as to the development of instrumentation to measure these water flows. He posited that understanding water movement would provide a direct path to a tree’s water status and thus a link to a tree’s oleoresin status and production. Together with Mirko Deml from the Institute of Instrumental Analytical Chemistry, Čermák invented a method for measuring water movement in tree stems and built the first simple device for measuring sap flow. He was setting up the first instruments when electrical engineer Jiri (Jura) Kučera started working with him as of 1973. Čermák progressed through the ranks to research worker (1970–1975) and independent researcher (1976–1977) while working toward his PhD. In 1977, he obtained the title of Doctor of Philosophy in the discipline of plant physiological ecology at the Agricultural University of Brno. Fortunately, he was able to defend his dissertation just before the restrictions of the late-seventies when many persons were fired because of their political views. He continued at the same university—later renamed the Mendel University of Agriculture and Forestry in Brno—as independent research specialist (1977–1984), research scientist (1985–1989), senior research scientist and leader of the tree ecophysiology research group (1990 and later). For context, it is important to remember that 1938 to 1989 was a period of great political and social upheaval in eastern Europe. Čermák’s home country experienced the occupation by Germany, the Second World War, a short period of recovery and a restoration of Czechoslovakia, and then in 1948, it became part of the communist east bloc. An attempted liberalization in the spring of 1968 was put down by a Soviet invasion of the country. These were very restrictive times. Information flow into and out of Czechoslovakia was greatly restricted and travel, especially for non-members of the Communist Party, was almost impossible. The term Iron Curtain was not a misnomer. In 1983, Čermák undertook his first international collaborative research project with Rainer Matyssek and Detlef Schulze near Bayreuth in Bavaria, West Germany. This was remarkable as Čermák was still a relatively unknown researcher toiling under strict communist rule. To his credit, Schulze recognized the great promise of the tissue heat balance (THB) sap flow instrument that Čermák developed, and was able to part the Iron Curtain to enable Čermák and Kučera to travel to Germany. This first external collaboration would lay the foundation for many more international partnerships that characterized the rest of Čermák’s research career. In 1988 in the USA, Dynamax’s sap flux measuring system based around external heaters and thermocouples was introduced and rapidly dominated. Čermák and Kučera’s second international collaboration began in Sweden in early 1989, before the Czech Velvet Revolution, and led to the first toe-to-toe comparison between the two methods. Thereafter, the THB method dominated in European tree water relations research. Čermák wasted no time after the opening of Czechoslovakia to the west. From 1991 to 1992, he was a Bullard fellow at Harvard Forest, Harvard University, USA. While in the USA, he attended his first international workshop meeting at Jackson Hole, Wyoming, leading to a collaborative chapter in a noted Academic Press book and to collaborations in the USA. During some successful international research campaigns, Čermák worked together with several scientists from Europe and the USA with whom he later started long-term collaborations and friendships. After his return to Brno, he became associate professor of tree ecophysiology at the Agricultural University in Brno as of 1992. On January 1, 1993, Czechoslovakia was separated in the Czech Republic and the Slovak Republic. At a scientific conference in 1991 in Pushchino near Moscow, Čermák met Nadezhda Nadezhdina, who was measuring sap flow rates in orchards at the Institute of Irrigated Horticulture in Melitopol, Ukraine. In 1995, he invited Nadezhdina to Brno to compare calculations of data sets of water fluxes. From then onward, Čermák formed a well-functioning team with Nadezhdina and her husband Valerij Nadezhdin, with strong expertise in the measurement of water fluxes. In 1999, Čermák was appointed full professor of tree ecophysiology at the Mendel University of Brno. After having spent 37 years in the Institute of Ecology, he returned in 2008—already at retirement age—to the Institute of Forest Botany, Dendrology and Geobiocenology of the same university where he remained active in research and international collaboration until his death. He passed away in Brno on December 23, 2021 at the age of 83 years. Relatives, close friends and colleagues said a last farewell during the funeral in Brno on January 7, 2022. During his academic career, he published over 300 scientific articles, conference papers, book chapters and research reports. Among these, 139 original, peer reviewed publications have been archived in the worldwide Web of Science database. These peer reviewed publications have received 5510 citations in total, and 15 publications were each cited more than 100 times. With a Hirsch-index of 44 Čermák became one of the most cited scientists not only of the Mendel University of Brno, but also of the Czech Republic. Čermák’s outstanding academic achievements were internationally recognized in the form of his membership in national and international institutions, for example as: vice chair of the IUFRO Working Group on Whole Plant Physiology, member of the editorial board of the journal Tree Physiology, member of scientific councils of several research institutions and member of the National Committee of the Academy of Sciences of the Czech Republic for the Geosphere-Biosphere. He has lectured at several Czech universities as well as at approximately 50 universities abroad, including the Universities of Oxford (UK) and Harvard (USA). He was involved in many international research projects and academic collaborations, some of which are presented and discussed in the section below. He was a sought-after reviewer of more than 60 scientific journals, an opponent of 35 dissertations or habilitations, as well as the supervisor of 20 Czech graduates and doctoral students, and 30 foreign doctoral students. During his lifetime, he received the following honors and awards: Dean’s Award of the Faculty of Forestry of the University of Applied Sciences for scientific achievements in 1978–1998; Award of the Czech Literary Fund, Section for scientific literature, Prague, 1981; Commemorative Medal of the Rector and the Academic Senate of the University of Applied Sciences Brno, 1986; Medal for Merit in Research in the field of tree physiology and long-term pedagogical activity, Mendel University of Brno, 2014. His footprint at the Faculty of Forestry and Wood Technology of Mendel University in Brno is indelibly engraved not only on the campus in Černá Pole, but also on the school forestry farm in Křtiny, where he conducted his research for many years, especially on the permanent research area in Soběšice. First, it is critical to note that Čermák’s research thrived with the support of two long-term co-investigators, Jiri Kučera and Nadezhda Nadezhdina, with whom several approaches to measure branch, root and stem sap flux were conceptualized and developed. Most often with these two individuals Čermák collaborated with researchers and scientists in Austria, Belgium, the Canary Islands of Spain, Germany, Italy, Portugal, Sweden and the USA where his techniques and approaches were brought to bear on interesting research problems and questions. Čermák’s focus on trees spanned from the use of an 87-m tall Liebherr 550 Crane with an 85-m jib to the of tall trees in an forest in the to under the roots of a tree in a forest near To these endeavors, he brought and but not for one example is his in a school by the European in as a and supervisor of an international group of scientists in the forests of He the of water and in to of was Čermák’s full and with from senior to student While Čermák collaborated with of scientists the in his career, four in this his with in and which the to the and in the USA and Belgium, which were and Čermák’s as a a and a The collaboration was in by Detlef when he with Čermák in Brno to the THB Together with Rainer Matyssek Čermák began first in the forest 30 of Brno in a and soon after in a forest of The focus of these was on the of and water flux as through and and of Čermák and Kučera were invited by Matyssek at the Institute for Forest, and Research in to the of The study that not was the These the to the and of the of the THB The started in 1989 when Čermák and Kučera collaborated on several projects with Čermák’s student and his two and at the University of Agricultural the collaboration The first project involved measuring sap flux and in a forest near Sweden this project was the first in which THB was to in a this with At the time it was to sap flow the study began with just two trees in 1989 up to sap flow on to trees in This was by a project in on For this project the THB method was by Kučera and Čermák to on small The were published in and several The collaboration was with the project in near an with one of the first in Europe. the focus was on THB in large trees and tree to the This research presented a study on tree sap flow and trees and then and one of the early of sap flow of with independent and Čermák’s to the USA and are in a September 1991 workshop at the University of National Research on Jackson was Bullard at Harvard Forest at the invited based on the with his sap flow He as one of the on a chapter in of and a to travel to with Kučera to with and on the water relations of The study was Research just of and in the of the noted that Čermák at that an in studies of tree and forest water relations in The of the research was to the to which of are or in the of in as to are from the Čermák been for years, an of the was to of and at of from to entire The study in a of The study began in July 1992, the of the sap flux of trees in from to at of to sap flux in two two and two on at and stem and For of and Čermák a to a tree and the stem under water and then to the with from on trees were in under water and the After for a period the stem was to sap flux and to the Čermák the of tree for the were to the of The and physiological were to tree and water The that the with high was to the environment and that in and were to of The of the in the simple led to group in and more on the of the The from the was of from the of while than from the of an of sap flow and from to and to tree from the forest and in the and in sap flow to In the to study the water relations of and tall trees with the of a in an forest and The study trees over years and with from to The study tree was with a of and a of approaches were the campaigns, with of the THB for the very large tree and of an stem sap flow and stem at to of water of the of in very large trees to in trees Čermák and a to the the in the support for the the period Čermák’s of with early career scientists with the same as with international Čermák to these an for the of close of trees in their the of and in understanding tree and forest water and an focus on technical in measurement under the most field from this period who worked with Čermák noted the and of a scientist than their and at full from to In 1995, research group at the University of started with soon with The collaborative nature of the research from a interest in forest ecology and in the and of The was to measure sap flow and to and water in a forest in near Čermák began the by into the stem of one of the study trees to the area and flow and the tree was Čermák attempted to the tree with a an his great This in Čermák his as he not to the and the tree to this flow and area were and stem sap flux were This first research was the of a long-term collaboration and that from until Čermák’s death. Čermák was very to and to where In he to Nadezhdina and to international and to scientists at the University of for some of this first in were two area and of and two in the the years, the long-term and was between the and Brno These collaborations were in a of from until Čermák and by a Czech student or to the University of for research or study of several Čermák the research group the and techniques that he and Nadezhdina for the measurement of sap flow of trees as well as of physiological He also these techniques for of data from trees to and to flow in trees were the method in water Čermák and Nadezhdina worked as a research Čermák was the of the THB which was by Nadezhdina with which been her doctoral research in Ukraine. before to Čermák’s in Brno, Nadezhdina a which later became as the heat field Čermák and Nadezhdina often for sap flow in their projects Čermák and Nadezhdina including conducted in in the Institute in with with whom published Jan Čermák at the research Czech Republic on Čermák. In a research project with the Institute of Forestry and and the University of Čermák on measuring sap flow rates of and trees for to the with the to water by or forests 1999, The the of the balance of trees and tree at the of trees and of sap flow the team of Čermák and Nadezhdina a and to data Nadezhdina on for the THB data which Čermák Čermák of sap flow to the This up data The research and in several scientific publications in international From until the collaboration between Čermák and his team with the University of was in and by several projects from the of the and the Czech Academy of During the academic student of the University of completed a on a study of the sap flow of and trees with root and water at the forest near Brno At Mendel University in Brno, the student was by Čermák and was a successful that in a scientific to Čermák’s Čermák was in his research with his and students. Between and 2021, researchers from Mendel University and from research group spent time at the University of Valerij Nadezhdin, Josef Čermák, Jan and The collaboration was not in 1995, Mendel University in Brno almost for up to to with Čermák and The first to Čermák’s at Mendel University a His was with and data around very The was also his He a on the in the and a small that he in the when when he the last the of two international on sap flow and water relations in in and research collaborations with in and publications until Čermák was a scientist and conceptualized several techniques that were often simple and to under field He also at and approaches that of the and of trees as well as of the and form and He was a in techniques and approaches as the of sap flow at the with at the and of studies at the with root and He to at the tree with the sap flow. Čermák’s research the of the of water from as well as the of this and for tree 1999, Čermák’s and would have the method for sap or the root by the with and Čermák’s these techniques to forest In the of his to tree and forest water relations, it to that Čermák also and techniques for the of He studied as an of the of trees and their physiological and He also published on volatile in the as of of tree or and the tissue heat balance method (THB) was by Čermák Čermák He the measure of water movement in tree and The of Čermák’s was to heat a the with an The and sap were to the flow of through the stem tissue as a of by a in with the the was well the heat balance to to sap flow In this flow was as of water time and thus a of water With this no was of this many and technical with the of Kučera to the Čermák Kučera 1977, At this method is globally in flux the heat field method is an to sap flow. 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