This seminar is hosted by the Oxford Centre for Tropical Forests, an Oxford Martin School Centre

Speaker: Professor Francis Halle, renowned French botanist and Botany Professor Emeritus of the University of Montpellier

Summary: The three dimensional branching of a young tree is never uncertain or random, on the contrary, it is controlled by a genetic programme called an “architectural model”. To help us understand this programme and identify a tree's architectural model, one has to take into account different units of growth and give an appropriate answer to the following three questions:

1. in the crown, are all the leafy shoots growing horizontally, or vertically, or is there a mixture of vertical and horizontal leafy-shoots?
2. on the trunk, are the branches regularly distributed, like in a Coffee-tree, or in whorls, like in a Pine-tree?
3. on the leafy shoots, are the sexual organs – either flowers, cones or sporangia – terminal or lateral?

To identify the “architectural model” of a young tree is not more than a first step. To analyse the 3-D form of mature large trees, the concept of “reiteration” is needed. Without reiteration, a tree remains unitary, as it is the case of archaic groups of plants – fossil trees, tree-ferns, Cycas, Araucaria, Palms, etc. Reiteration is a modern mechanism which allows a tree to become a colony. Modern trees are colonies, they are much bigger than unitary trees, and they have a much longer life-span with some tree-colonies becoming virtually immortal.

Venue: Large Lecture Theatre, Department of Plant Sciences, South Parks Road, Oxford, OX1 3RB

This seminar will be followed by drinks, all welcome.

All welcome. To book a place, please visit https://bookwhen.com/octf

About the Speaker

Francis Hallé is a professor of botany at the University of Montpellier, France. As a co-founder of the famous Radeau des Cimes canopy raft and leader of its expeditions until 2001, he has dedicated his life to researching tropical plants, particularly low-altitude rain forests, and carried out eight missions to study the canopy of equatorial forests. He is a pioneer in exploring life in the treetops of tropical forests, using a blimp-borne inflatable raft that rests on the tops of the trees of the canopy. "The rainforest canopy is still a largely undiscovered layer of the planet. Francis Halle's pioneering treetop expeditions are carrying out vital research into what makes the world's rainforests tick" (Gil Gillespie, Frontiers, 1998)