Photo of Pieter Baas in tulip bed

The IAWA mourns the recent loss of Professor Dr. Pieter Baas, one of the most distinguished scientists in plant anatomy and wood anatomy and the greatest advocate for worldwide cooperation of wood anatomists in our times. Pieter Baas passed away in Leiden, the Netherlands, on April 29th, 2024, the day after his 80th birthday. He was an emeritus professor at Leiden University, and a life and honorary member of IAWA.

He started studying biology at Leiden University in 1962. Between 1968 and 1969, he studied with Professor C.R. Metcalfe at the Jodrell Laboratory of the Royal Botanic Gardens, Kew. In 1975 he earned his PhD in wood anatomy from Leiden University, with a thesis on the Aquifoliaceae. He became a professor of plant systematics at Leiden University in 1987 and Director of the Rijksherbarium in 1991. Starting in 1993, he engaged in a six-year struggle to preserve the herbarium and wood collection. He was successful. In 1999 he was appointed director of the National Herbarium of the Netherlands, an institution which resulted from the combined herbaria of Leiden, Utrecht and Wageningen universities. He retired in 2005, but continued working on wood anatomical projects until a week before his death.

Dr. Baas was Executive Secretary of IAWA from 1976 to 1981. Together with Emma van Nieuwkoop, he was the driving force behind the IAWA Bulletin between 1970 and 1979 and was editor-in-chief of the IAWA Journal, the continuation of the IAWA Bulletin from 1980 to 2019. His great contributions to plant anatomy, forestry, wood science, and wood anatomy were significantly recognized by the international community. He became a member of the Royal Netherlands Academy of Arts and Sciences in 2000. He was an elected fellow of the International Academy of Wood Science and a corresponding member of the Botanical Society of America. In 2023, he won the Linnean Medal of the Linnean Society of London and he became a Knight in the Order of the Netherlands Lion in 2005.

Pieter Baas always enjoyed promoting IAWA
Taken by Elisabeth Wheeler from the 2015 IAWA meeting in Tervuren, Belgium

Elisabeth Wheeler misses Pieter very much. “It hurts to write this paragraph because I would much prefer to be writing an e-mail to Pieter. He was the best of friends and colleagues, with his enviable social skills and wealth of wood anatomical knowledge. At every IAWA scientific meeting, Pieter was the one you could count on to ask good questions of any speaker. At every IAWA social hour, he was the one making toasts and thanking organizers, and, of course, happily welcoming new IAWA members and chatting with everyone. Selling IAWA publications was one of his favorite activities as anyone who ever attended an IAWA meeting well knows. He was exceptionally generous and encouraging to young scientists and readily shared his expertise. Anyone who visited Leiden enjoyed his hospitality and oftentimes “a spin” around the Dutch countryside with Pieter at the wheel. His scientific output was prodigious, and he supervised work on many families resulting in some classic wood anatomical monographs, e.g., Sapindaceae with R. Klaassen and Rosaceae with S-Y Zhang. He was vital to obtaining support for InsideWood. Thank heavens for Zoom meetings as they made it possible to visit with Pieter on a regular basis. I am so going to miss him.”

Lloyd Donaldson recalls “I first met Pieter at the Botanical Congress in Sydney, Australia in 1981. Pieter travelled extensively and visited New Zealand for the Pacific Wood Anatomy meeting in Rotorua in 1994 and again for an IAWS executive meeting in 2018. I served with Pieter on the IAWS executive for the next 3 years with numerous meetings including EC meetings in Corvallis, USA and Guadalajara, Mexico, and another Pacific wood anatomy meeting in Bali. Pieter served as leader of the Academy Board, and in 2018, a small committee was formed to pursue greater representation of females and to encourage the nomination of fellows in some under-represented regions including South America and Malaysia. Pieter suggested Barb Lachenbruch, Roberta Farrell, and Ruben Ananias on the committee. [All three subsequently agreed to assist]. Pieter was asked by Rob Evans to act as chair and he agreed. Pieter was instrumental in nominating many female candidates for IAWS fellowship and strongly supported gender and regional balance in the Academy. I was able to visit with Pieter during a visit to Leiden after the IAWS meeting in Gratz, Austria just after I took over as co-editor of IAWA Journal and was treated to the famous tour around Leiden and the surrounding countryside (in search of an authentic Dutch windmill). We have to acknowledge Pieter's academic contribution with a massive 510 articles, books, editorial notes and reports, 13738 citations, and an h-index of 57 (Google Scholar). This doesn’t include all of the IAWA Bulletin and IAWA Journal articles that received his editorial attention over the 40+ years he served as editor. Pieter also recently served as associate editor for the International Journal of Wood Culture.”

Photo of Pieter Baas (from left to right the third)
Taken by Frederic Lens during a 2019 meeting in Leiden, the Netherlands

Peter Gasson considers Pieter to be his friend, colleague and mentor since he met Pieter at Kew in the late 1970s. “I am privileged and honoured to have worked with him on the IAWA hardwood and softwood lists, collaborative efforts with many other wood anatomists which have stood the test of time and are the basis for InsideWood. He has been an incisive editor and co-author, and a major participant in all the IAWA meetings I have attended. I have particularly good memories of the PROTA wood anatomy workshops in Montpellier (2007) and Kumasi (2010) which contributed to PROTA Timbers 7(1) – (704 pages!) and 7(2) – (804 pages!), and the two wood courses he, Elisabeth Wheeler and I taught at the Arnold Arboretum in 2015 and 2017. I remember at one IAWA dinner sitting with Pieter and a couple of retired wood anatomists, one of whom commented that a young speaker had made a statement as though he’d just discovered it, but it had been known thirty years ago, and Pieter gently responded with ’well, it’s better reinventing the wheel than forgetting about it altogether!’. That sums up Pieter’s generosity of spirit. I visited Pieter in late March and saw him for the last time. I will miss him enormously.”

Frederic Lens remembers him as a wonderful professor and friend. “In the early 2000s, I met Pieter for the first time in Leiden when I started my PhD. I proudly presented him with my best wood anatomical slides. After looking at them for a couple of seconds, he replied to me: ‘Sorry Frederic, but these are lousy sections; your knife is not sharp enough’. His Dutch directness was at that moment hard to swallow, but he was absolutely right. ‘Thank you Pieter.’ He liked a good glass of wine, very much enjoyed company, and remained active as a wood anatomist until his last week when he was responding via email to reviewers’ comments concerning our last manuscript we worked on. Pieter, I am grateful to follow in your footsteps, and we will make sure your Leiden legacy won’t be forgotten. Thank you for everything.”

Photo of Pieter Baas
Taken by Peter Gasson on a conference tour for the IAWA meeting in Montpellier, France, 2004

Marcelo Pace feels privileged by knowing him. “It is very hard to lose a friend. But one realizes that the loss is not entire, as we keep parts of the beloved person with us. I met Pieter in Vienna during the IBC in 2005. I was a graduate student then, starting my MSc. I approached him and said: ’It is an enormous pleasure to meet you, I am a huge fan of your articles’, to which he responded ’the pleasure is all mine’. Following I said: ‘I am learning so much’, and he humbly responded ‘Aren’t we all?’ To a graduate student, a renowned Professor to say these words was unimaginable. I had the privilege to be his student, friend and colleague. He hosted me in his house more than once, we met in Brazil and Mexico several times, and we had a great time working on the Bark List in both Brotas (Brazil) and Madison Wisconsin (USA). One would walk with him, say the name of a plant, i.e., a Bignoniaceae Brazilian tree, and he would say ‘Am I thinking of paratracheal axial parenchyma, all storied elements, homocellular rays?’. Every minute with him was both a joy and a learning experience. Pieter was fundamental to my career, as he made recommendation letters that led to where I am now. He also trusted me (and Lloyd) to follow him as editors-in-chief of the IAWA Journal, something huge giving his love and dedication to our Journal. I can’t say how much I am thankful to him, and how much I miss sending him an email and getting an immediate response. His absence is still hard to grasp, but I know he will be with us forever.”  

As an internationally renowned wood scientist, Prof. Dr. Baas has made irreplaceable contributions to the academic progress and long-standing friendships of our IAWA family. He was enormously helpful in supporting and training young students and early-career researchers in wood anatomy around the world. He worked tirelessly and strenuously throughout his life. With Pieter’s passing, the IAWA has lost a remarkable member. All his work for IAWA and its members will long be respected and remembered. We will miss him very much.

Elisabeth Wheeler, Lloyd Donaldson, Peter Gasson,
Frederic Lens, Marcelo Pace and Yafang Yin