Corpus Christi College Cambridge announced last week the death of Professor Oliver Rackham, aged 75, who studied the British countryside, especially trees, woodlands and wood pasture.
Seminal books included Trees and Woodland in the British Landscape and Ancient Woodland: its history, vegetation and uses in England. He was awarded an OBE for services to conservation.
Consultant and former chair of the Ancient Tree Forum Neville Fay said: "He was caring and compassionate on conservation, making him such an important contributor to current thinking.
"Oliver had an encyclopaedic knowledge and was a giant among minnows. He was eccentric and had strong opinions not everyone agreed with but no one could discount. He was also a lovely man."
Suffolk County Council woodland advisor Gary Battell said: "He was massively important – a great communicator, researcher and observer.
"Oliver was a guiding light and original thinker. I'm sure he influenced the actions of many people within the woodland sector."
Professor Rackham was born in 1939 and had a lifelong association with Corpus Christi, studying there as an undergraduate before specialising as a historical ecologist and historian of landscape.