International Association for Lichenology

Thomas George Allan Green

Thomas George Allan Green

Professor Thomas George Allan Green is a terrestrial ecologist, a botanist and a lichenologist. His studies have been mainly focused on plant physiology, covering a wide scope of organisms – from trees and ferns, to mosses and lichens. However, most of his scientific work, and perhaps the papers with the highest impact in the scientific community, have dealt with lichens.

Although originally from the UK, with a PhD from Oxford University, Prof. Green moved early in life to his second homeland, New Zealand, where he worked on adaptation strategies of Pseudocyphellaria spp. and other machrolichens of the southern temperate rainforest. In his third homeland, Germany, he worked with Dr. Otto Lange, Dr. Ludger Kappen, Burkhard Büdel and Dr. Burkhard Schroeter on some of the most significant lichen physiology experiments in recent decades. Over the past 12 years, I have had the good fortune to share with Dr. Green his fourth homeland, Spain. For his scientific work here, Dr. Green was awarded the prestigious Spanish grant “Ramón y Cajal”.

Dr. Green can be considered one of the first who laid the basis for our modern understanding of the physiological functions and adaptations of lichens in their habitats. His long list of very valuable, refereed publications began in 1974 with a paper about lichen physiology published in the journal, New Phytologist. Later he investigated the the influence of major environmental parameters on CO2 exchange in lichens, resulting in seminal papers about carbon dioxide exchange and diffusive resistance of CO2 in relation to water status in lichen thalli.

Prof. Green always uses the highest technical standards for his instrumentation, and stimulates interdisciplinary cooperation to address important issues in plant ecology. He contributed to the development of automatic and portable instruments in order to carry out accurate measurements under extreme climatic conditions. Most of this work deals with the adaptation and physiological performance of lichens under the extreme conditions of continental Antarctica, mainly in the challenging region of the Dry Valleys, where he was the leader of some of the most remarkable Antarctic New Zealand international expeditions.

More recently, however, a significant part of his activity has moved to the study of biological soil crusts, not only in polar habitats, but also in alpine and arid regions. His many reviews about lichen ecology, biodiversity and ecophysiology have become especially renowned. Even more impressively, Dr. Green represents, on the highest level, the perfect balance between research and teaching at our University, something we all strive to achieve. In fact, in 2012, in recognition of his amazing academic merits, he obtained the higher doctorate in Science by Oxford University. Dr. Green has been most helpful to colleagues and students everywhere in the world. As many others before me, I have also benefited from his extensive knowledge, and his apparently endless source of bright ideas, for many years. We owe him the deepest gratitude for stimulating discussions, fair and fruitful cooperation, his teaching, and many other kinds of help and support. We are all extremely happy to see the Acharius Medal presented to him.

– Leopoldo G. Sancho, Madrid (Spain)