The buttes: unique nature reserves
The Buttes du Parisis and the Buttes de Montmorency are natural areas of prime importance within the Agglomération. On the Buttes du Parisis, straddling Cormeilles-en-Parisis, Franconville-la-Garenne, Montigny-lès-Cormeilles and Sannois, a Domaine Régional has been set up, enabling visitors to observe and preserve a unique natural environment just fifteen kilometers from the capital. More than 350 plant species can be found here. While most of this heritage is common to these areas, particularly the trees (beech, oak, alder, etc.), there are some rare species. These include the false rye barley, the ivy-leaved orobranch, the acrid fleabane and the prolific carnation. As for the flora, birds are plentiful: several dozen species have been observed. While wrens, tree chaffinches, robins and blue tits are the most common, there are also chickadees, greenfinches and black woodpeckers. Even rarer but already observed, kestrels and long-eared owls may nest or hunt here. As for amphibians, some ponds are home to agile frogs, common toads and natterjack toads, which find sufficient nutrients in the former quarries. Reptiles such as the fragile orvet, which looks like a snake but is in fact a lizard, can be found here, as well as beetles and numerous butterflies, some of which are rare and have poetic names: the Petit Mars Changeant, the Demi-deuil or the Flambé. As for the Butte de Montmorency, even though the communes of the Val Parisis conurbation concerned (Bessancourt, Saint-Leu-la-Forêt, Taverny) make up only a small part of the latter's 2,200 hectares, there are similarities with the Buttes du Parisis, but also a few differences: there are Scots pines, peat bogs and, on the fauna side, in addition to birds and insects, the presence of roe deer, wild boar and foxes.
A hydrographic network marked by the Seine River
It's the presence of the Seine, just a few kilometers to the south-east of the Val Parisis conurbation, that marks the area's hydrography. Between Cormeilles-en-Parisis and Herblay-sur-Seine, the Seine has, here as elsewhere, gained in quality, allowing flora and fauna to thrive. The Seine is home to pike-perch, pike, carp and roach. Over the past twenty years, a number of environmental preservation projects have enabled an increasing number of fish to return to the river. But the most emblematic operation is the one on the island of Herblay-sur-Seine: completely uninhabited, it has been a refuge for an extremely important fauna and flora for over a century. If man has altered the appearance of the site, it's to create the conditions necessary for the development of this inaccessible natural area. Classified as a "sensitive natural area of departmental interest", the 16-hectare site is home to over 40 species of birds, a dozen different insects, butterflies, reptiles, amphibians and even a few mammals, including the mole and the coypu. There are also around a hundred plant species, most of them indigenous, some of them very rare. Eventually, observatories will be set up on opposite banks.
Numerous urban parks..
Every town in the Agglomération has at least one car-free park, garden or driveway where nature can flourish in peace and quiet. Examples include the landscaped Bassin des Moulinets in Eaubonne, the vast Parc Schlumberger, set high above the town and offering splendid views of the surrounding area, La Source in Montigny-lès-Cormeilles, created on the site of a former mineral water factory, and the coulée verte in Plessis-Bouchard. And there's no shortage of new initiatives: the Parc Chabrand-Thibault, on the heights of the Buttes du Parisis, has just been inaugurated. All in all, if you take a map of the Agglomération, you'll see that dozens of sites dot the territory: you're never far from a natural space here.
...remarkable natural spaces..
In addition to the areas created by man, our actions are also aimed at preserving natural areas that have always been natural. The Domaine Régional de Boissy in Taverny, for example, is a small 137-hectare conservation area in the heart of a densely populated urban environment. In the same spirit, Bois Barrachin was opened to the public in 2022. Forbidden to the public for almost 70 years - a company having acquired the site - it is now partially accessible to all: almost 5 hectares of totally natural spaces have been returned to the inhabitants, out of the existing 20, allowing them not only to discover preserved nature (century-old trees, clearings, birds and squirrels are at home here), but also to link several districts of Beauchamp.
... and a forest in the making!
It's certainly the largest and most impressive natural development project in the Agglomération, and probably in the whole département: the Forêt de Maubuisson is indeed a future major element of the Agglomération's natural heritage. The principle is simple and far-reaching: since 2019, on the plain between Herblay-sur-Seine and Frépillon, passing through Pierrelaye, Bessancourt and Taverny, what will eventually be one of the green lungs of Greater Paris has been planted here. In concrete terms, 1,340 hectares will eventually be planted, creating an immense forest: the largest forest created in France since Colbert! Although planting began in 2019 (hundreds of thousands of tree seedlings have already been installed, representing some thirty species selected by the Office National des Forêts), it is continuing at an advanced pace.
