In the Pierroton district of Cestas, just off the main road that leads from Bordeaux to Arcachon, a monument to the agronomist François J...

Chambrelent: the architect of the Landes forests

In the Pierroton district of Cestas, just off the main road that leads from Bordeaux to Arcachon, a monument to the agronomist François Jules Hilaire Chambrelent can be seen. It was Chambrelent’s work throughout the 19th century that went some way towards making much of les Landes of south-western France the pleasant and hospitable place we are familiar with today.

In the past, it had been a very different story. South of Bordeaux, the inland area was a succession of vast, barren plains that were frequently flooded. This extensive sandy marshland, which became known to many as the “French Sahara”, was a particular challenge to many pilgrims as they headed south towards Santiago de Compostela in north-western Spain.

Towards the end of the 18th century, the engineer Nicolas Brémontier (Inspecteur General for Ponts et Chaussées, Bridges and Roadways) had shown that it was possible to use trees to hold back the dunes of the Atlantic coast. Mass plantations of maritime pines (Pinus pinaster) followed – this local species boasts strong roots which fix and consolidate the sandy land at its base, and when its needles fall they form a “carpet” which slowly evolves into fertile and solid soil. This technique was to inspire fellow engineer Chambrelent in the following years…

Chambrelent was born in 1817 in Martinique. He studied at École Polytechnique and École Nationale des Ponts et Chaussées in Paris. Between 1848 and 1865, he was based in Bordeaux as an engineer for the Gironde hydraulic work department. He subsequently took up other positions in the Alps before returning to Bordeaux in 1873 as head of the hydraulic unit and then Inspector General for a three-year period ahead of his retirement in 1882.

In 1849, Chambrelent had personally acquired 500 hectares of land in Cestas (in a part of the town known at the time as Saint-Alban). His self-defined task was to establish how forests might develop on land that alternated between periods of flooding and periods of drought. His research showed this could be achieved by breaking down the top level of soil and then deploying a large-scale network of ground-level irrigation channels, thus ridding the land of otherwise stagnant water. The soil could then be used to accommodate maritime pines and oaks (Quercus suber, or cork oak,  and Quercus ilex, or holly oak).

In case that all sounds a bit too simple, rest assured, Chambrelent later provided more detailed information about his findings in the 1887 book “Les landes de Gascogne, leur assainissement et leur mise en culture. Exploitation et Débouchés de leur produits.”, and in the specialist review Annales des Ponts et Chaussées. Chambrelent had also presented his findings at the 1855 Universal Exhibition in Paris, which did much to raise his profile and indirectly resulted in Napoleon III awarding him the Croix d’Officier de la Légion d’Honneur. Then, in 1857, a law largely based on Chambrelent’s recommendations was passed and provided the blueprint for the “assainissement et mise en culture des Landes de Gascogne”. The stage was set for the transformation of the area into the green and pleasant landscape which remains today.

"He cleaned and embellished the moors and brought ease to a deprived area."
Chambrelent basked in glory but for many the success had a bitter taste. Chambrelent had been inspired not only by Brémontier but by fellow Ponts & Chaussées engineer Henri Crouzet, and the latter’s essay on “La transformation des Landes de Gascogne”. At the 1855 Exhibition, while Chambrelent collected the plaudits, Crouzet went home with a lowly medal in recognition for his “services to the event”. Other unsung pioneers include dune-owners Guillaume and Louis Mathieu Desbiey who had carried out similar research one hundred years earlier but whose work was also left in the shade by Brémontier and Chambrelent.

It is therefore Chambrelent who is celebrated by the monument, which was officially unveiled on September 11th 1907. It had been funded by the Touring Club de France, the association which sought to promote and develop “tourism in all its forms” between 1890 and its demise in 1983.

The monument stands just a few hundred metres away from the property where Chambrelent carried out his life-size research. The mansion which he built there in 1863 still remains; it and the surrounding land were later passed on by the Chambrelent family to the French State and are now home to the Unité Expérimentale Forêt Pierroton, part of France’s national agronomic research institute (INRA, Institut National de la Recherche Agronomique).

Meanwhile, it was in Paris that Chambrelent died in 1893, although he was buried in a neo-classical vault at Chartreuse cemetery in central Bordeaux. Twenty kilometres away in Cestas, his influence continues to be acknowledged though: as well as the roadside monument, his name has been given to a housing estate and the local football pitch!

The grave chapel in central Bordeaux where Chambrelent is buried.
The entrances to Chambrelent football pitch and housing estate in Pierroton (Cestas).
However, Chambrelent’s most lasting legacy will be the massive forests (and irrigation ditches) that cover 900,000 hectares of now-hospitable land throughout south-western France. The large swathes of green that can be seen on satellite photos of the area are therefore, in many ways, largely man-made… and François Jules Hilaire Chambrelent is one of the people to thank!

How the Landes gradually turned green during the 19th century (source: INRA), and (right) how the area looks today on Google Earth.


  1. "chapel-like vault": in French it's not chapel-like, it IS a chapel - une chapelle funéraire.