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31 August 2020 In Memoriam
Fritz Hans Schweingruber 1936–2020
Georg von Arx, Paolo Cherubini, Patrick Fonti, Daniel Nievergelt, Loïc Schneider, Kerstin Treydte, Anne Verstege, Holger Gärtner
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Fritz H. Schweingruber, pioneer of tree-ring research and wood anatomy, passed away on January 7, 2020, at the age of nearly 84. Fritz was born on February 29, 1936, in Krauchthal (Canton Bern, Switzerland). From 1956 to 1965, he was a primary school teacher and an organist. Although he liked teaching, he discovered his curiosity for botany and archaeology. This was the beginning of what turned out to be an outstanding scientific career. He enrolled at University of Bern and took classes in botany, zoology, geology and pre- and early history. In 1972, he obtained his doctorate in botany from the University of Basel, where he was appointed professor in 1976.

Since 1971, Fritz was based at the Swiss Federal Institute for Forest, Snow and Landscape Research WSL (Birmensdorf, Switzerland), where he established one of Europe's first tree-ring labs, which developed into one of the largest worldwide. Among the lasting contributions to our field are more than 200 journal articles and 39 books, among which include (1) “Tree Rings: Basics and Applications of Dendrochronology” (Schweingruber 1988) and “Tree Rings and Environment Dendroecology” (Schweingruber 1996), which are classics, (2) the northern hemispheric network of tree-ring density data from 350 sites established with colleagues from UK and Russia, which is an important backbone of the ITRDB, (3) a worldwide unique collection of anatomical micro-sections of 5000 tree, shrub, herb and graminoid species, (4) the “International Dendroecological Fieldweek” initiated in 1986, which inspired a number of courses worldwide such as the continuing “European Dendroecological Fieldweek”, and (5) the international course on “Wood Anatomy & Tree-Ring Ecology” running since 2001. These and further milestones of Fritz' extraordinary life are summarized in more detail in other obituaries (Büntgen et al. 2020, Crivellaro and Gärtner 2020, Urbinati et al. 2020).

Colleagues and friends at the WSL as well as in the scientific community experienced Fritz as a very curious, dedicated and charismatic person. The following thoughtful recollections from our group, mostly from Fritz' last years as a retired member of our research group, illustrate this.

Whenever Fritz visited the lab and encountered students or guests working on samples, he was eager to engage in a scientific exchange, regardless of hierarchical position and background. On these occasions, he used to unpretentiously introduce himself like “Hello, I am Fritz”. Many of them were wondering afterwards who they just met. And many of them found themselves gaping in amazement after learning it was Fritz Schweingruber.

Conversely, when people visited Fritz in his small “Stöckli” office searching for advice to a methodological or scientific question, he immediately paused his – typically microtome – work and took unlimited time to share his extensive experience and knowledge. A couple of days later he would approach the same person again asking if it worked out and what she or he found out.

At the ceremony for his 80th birthday on February 29, 2016, Fritz said “I actually just turned 20 years old” in allusion to the leap year rhythm. Although meant to provoke laughter, this statement certainly held with respect to his youthfulness and never-fading curiosity and dedication.

His dedication also showed during an extended sampling trip in Italy. At the very last day, Fritz and his companion took a bath in the sea to relax from the strenuous campaign. In the meantime, someone robbed their car including all tree cores. Others may just have gone home, bemoaning their fate and leaving it at that. Not so Fritz and his companion. Indeed, they went home, but just to come back and repeat the identical sampling campaign a few weeks later.

Fritz had an excellent memory for sites he sampled. Sometimes, when the written records of a site lacked clarity with many years in between, he could still very clearly describe how a specific site was reached. His excellent memory also included details to the site itself, his company, and funny food stories such as “the fish head soup was filled with mosquitos”.

He liked to hold up a small shrub and state “this is a tree” – in allusion to the largely identical xylem structure and the occurrence of annual growth rings. This example also shows a unique gift to explain his view and understanding in simple words, much to the benefit of his audience.

Fritz' charismatic teaching skills were further supported by his enthusiastic body language. When explaining people the processes of tree growth, his gestures could add so much information to his lecture that one was close to imagine him turning into a tree himself.

We will miss Fritz as the founder and outstanding member of our WSL tree-ring lab, and his vast knowledge and experience he freely shared whenever requested. We will also remember his limitless curiosity and never-ending passion to work in the lab, exchange and discover new scientific territory. A true father of modern and, perhaps, future dendrochronology. His intellectual legacy will continue to inspire us and scholars around the world.

–Contributed by the WSL Dendrosciences Group



Büntgen, U., M. K. Dobbertin, and H. Gärtner, 2020. Schweingruber's cosmos of inspiration. Dendrochronologia 60:125680. Scholar


Crivellaro, A., and H. Gärtner, 2020. Fritz Hans Schweingruber (1936–2020). IAWA Journal 41:125–127. Google Scholar


Schweingruber, F. H., 1988. Tree Rings: Basics and Applications of Dendrochronology. Springer Science & Business Media. Google Scholar


Schweingruber, F. H., 1996. Tree Rings and Environment Dendroecology. Paul Haupt, Bern, Switzerland. Google Scholar


Urbinati, C., M. Pividori, and P. Cherubini, 2020. “The answer, my friends... is written in the rings”: Un ricordo di Fritz Hans Schweingruber (Fritz). Forest@ - Rivista di Selvicoltura ed Ecologia Forestale 17:27–29. Google Scholar
Copyright © 2020 by the Tree-Ring Society
Georg von Arx, Paolo Cherubini, Patrick Fonti, Daniel Nievergelt, Loïc Schneider, Kerstin Treydte, Anne Verstege, and Holger Gärtner "In Memoriam
Fritz Hans Schweingruber 1936–2020," Tree-Ring Research 76(2), 106-107, (31 August 2020).
Published: 31 August 2020

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