Log in

Editor's Picks

The oak tree in Skjomendalen © Gerhard Sørensen-Fuglem and Cecilia Piccirilli Bjerkeset
An oak grows north of the Arctic Circle in Norway
Website Editor | Aug 14, 2023
Unusual symptoms linked to phytoplasma infection in Quercus humboldtiii, Colombia © Eric Boa
Symptoms linked to phytoplasma infection found in Quercus...
Website Editor | Aug 06, 2023
Different names are being used for one species.
Website Editor | Jun 20, 2023

Plant Focus

A small but mature Alabama sandstone oak producing acorns © Patrick Thompson
A Critically Endangered dwarf oak 

Jean-Louis Hélardot: a Passion for Understanding Oaks

PDF icon Full text available for IOS members only. If you are a member, you need to log in.

To create an account click here; if you have already registered, click here to become a member.

Individual articles can be purchased for U$S 10. If you would like to purchase an article, email a request to website@internationaloaksociety.org

Béatrice Chassé

Published May 2022 in International Oaks No. 33: 173–185


Having acquired the property that was to become the Arboretum des Pouyouleix (France) in June 2003, Gérard and I arrived that summer in our new house, a perfect ruin inside and out. The renovation was not to begin until October, so we basically camped out in the house for three months with a makeshift bathroom, a new SMEG, and a computer.

One day, coming home, I hear Gérard yell out, “You have to come and see this.” He was sitting at the computer where he had just discovered Oaks of the World, (a part of) Jean-Louis Hélardot’s website that I’m willing to bet few of you are not already familiar with. In that moment we suddenly knew exactly what we had gotten ourselves into when we decided to build an oak collection.

This discovery also led, a few years later, in 2008, to encountering the charming individual behind the website and the wonderful oak collection he has built, the Arboretum du Passadou, in the hamlet of La Vergnotte, in the town of Mansac, near the city of Brive- la-Gaillarde (France).

What follows is a poetically licensed mix of my visit there on June 16, 2021 and 13 years of friendship, collaboration, and visits to our respective arboreta.


Chassé, B. 2021. In Our Garden. International Oaks 32: 155-182.

Hipp, Andrew L., Paul S. Manos, Marlene Hahn, Michael Avishai, Catherine Bodénès, Jeannine Cavender-Bares, Andrew A. Crowl, Min Deng, Thomas Denk, Sorel Fitz-Gibbon, Oliver Gailing, M. Socorro González-Elizondo, Antonio González-Rodríguez, Guido W. Grimm, Xiao-Long Jiang, Antoine Kremer, Isabelle Lesur, John D. McVay, Christophe Plomion, Hernando Rodríguez-Correa, Ernst-Detlef Schulze, Marco C. Simeone, Victoria L. Sork, and Susana Valencia-Avalos. 2020. Genomic landscape of the global oak phylogeny. New Phytologist 226: 1198-1212.