Its construction is due to the collaboration of M. de Gayffier, curator of the forests of the Marne and Seine-et-Marne, who had already built the 1878 pavilion, and of M. Leblanc, a young architect of civil buildings. Whereas the 1878 pavilion was made of worked wood, like any other chalet, the 1889 pavilion is made of logs, which gives it a very special character.
It is made entirely of bark-covered wood, and consists of a ground floor with an exterior gallery and a first floor forming an interior gallery of the most graceful effect. The ground floor room thus forms a sort of hall surrounded by a colonnade of trees in their natural state, with capitals reminiscent of Hellenic architecture. 1400 cubic metres of wood were needed for this construction, and all of this wood was taken almost exclusively from the forests of Seine-et-Marne, particularly from those of Fontainebleau and Montceaux, with a choice of different species, of course. There are only two exceptions in this assemblage of French wood. Only two pines, extracted from the Fontainebleau forest, are of foreign origin. These are the so-called Lord Weymouth pines, planted at the end of the reign of Louis XVI, on the occasion of a Chinese festival given to Queen Marie-Antoinette in the forest of Fontainebleau, and which had been left there. These pines had multiplied and there are still about twenty of them on the replacement site where the party was held.
The gathering of all these woods is already very instructive in itself, for it fixes the attention by its artistic arrangement, and at the same time as one admires it one is obliged to realise the technical value of the elements employed.
Against the walls are arrays of wooden objects and the tools used to make them. On the floor, huge logs of all sizes are presented to us as specimens of old tree growth and as samples of the mechanical cutting obtained with the help of the perfected tools in general use in the forests of the State.
These advanced instruments are represented by a vertical and a circular saw, which indicate the many ways in which the wood can be cut.
The age of the trees is indicated by figures which, although not extravagant, are no less interesting. Among the trees that support the gallery, both outside and inside, there are beeches that are one hundred and sixty years old, pedunculated oaks that are one hundred and fifty years old, birches, poplars and hornbeams that vary in age from ninety to one hundred and twenty years. An oak in the Trois-Fontaines forest in the Marne is two hundred and fifty years old. A pistachio tree in the Atlas, near Algiers, is three hundred years old. A cork oak in the province of Oran is the same age.
Each forest district cuts wood according to the quality of its species and their appropriation. A specimen of each cut initiates us to this appropriation. The Vosges, the Jura, the Loiret, the Tarn cut their wood for joinery and cabinet making; this last department also supplies wood for staves, vats, muids and casks. The Pyrenees provide wood for carpentry and railway sleepers, beams
and joists. The Bouches-du-Rhône, with the country elm, supplies the carpentry industry, just as the oak of the Côte-d'Or is used in the construction of the wagons of the Paris-Lyon-Méditerranée company. The North provides wood for the inland waterways and the Loire-Inférieure for the planking.
Finally, the ground floor room still offers three extremely curious dioramas.
The first one shows the Combe de Péguère, near Cauterets, in the Hautes-Pyrénées. The second and third give us the spectacle of the torrents of Riou-Bourdoux, in the Basses-Alpes, and of Bourget, in the Basses-Alpes. This is a very ingenious way of giving us an idea of the work carried out by the Forestry Administration for the reforestation and grassing of the mountains.
The credit for this idea goes to M. Demontrey, one of the most eminent conservators of our forests, who had as a collaborator in the execution of these dioramas, M. Gabin, a painter and decorator of great talent, who acquitted himself all the better for having studied on the spot the landscapes and the works he was going to have to interpret.
But let us first examine the first and only floor of the pavilion. This is the most learned and technical part of the forest exhibition. It includes the collection of all the insects and fungi that are the scourge of our forests, and next to it the collection of leaves, flowers and fruits of our trees, and finally the samples of our forest lands.
Some of the parasitic fungi that are the ruin of the most beautiful trees are presented in showcases. Each species has been caught in flagrante delicto, as it were, and often next to the culprit is the body of the crime, which allows us to judge the magnitude of the crime.
This is a Polyporus nidulans decomposing a dead branch of an oak tree, in December 1877, in the forest of Orleans. It was a Polyporus Dryadeus that had killed the heart of an oak stump, on March 21, 1882, in Rebeuville, in the Vosges. It was a Rosellinia puercta that killed the roots of an oak tree in August 1875, the wretch!
Fortunately, on the other hand, there are different manifestations. In jars are fruits, seeds, perfumed essences, jams, jellies, preserves of all kinds and even orange wine, forest products. Then there are samples of the various coals that can be obtained from our woods. We then move on to the soil of our forests, which varies in nature depending on the area. Here we have limestone from the Jurassic period, there marble from the Pyrenees, sandstone from the Vosges, granite from the Rhine, Yonne and Puy-de-Dôme, quartz from the Allier, millstone from the Marne and Aisne, etc. And we go back down to the ground floor to see the dioramas again.
At about 1300 metres above Cauterets, in the Hautes-Pyrénées, stands the Péguère peak. A dislocation of the mountain determined the Combe of this name which represents us the first diorama, and which constituted for the thermal establishment a perpetual danger.
From the autumn of 1885, work began, and has continued to this day, with the aim of fixing the crumbly earth of the mountain, immobilising the blocks and preventing landslides. On the eastern slope of the same Péguère peak there is another Combe which is absolutely safe, simply because it is grassy, overgrown and wooded from base to summit. So for the last four years, we have been trying to cover the Combe de Péguère with patches of grass interspersed with shrubs. Where the grass ran the risk of not growing, stone coverings were built, in rubble, brought by a Decauville railway which is operated without a machine, by means of a combination of slopes calculated to ensure its speed or its stops.
This interesting task is carried out in the midst of considerable danger. But, thanks to the experience and intrepidity of the workers and those who direct them, no accident has ever occurred. In short, the action of frost, water infiltration and atmospheric phenomena is neutralised. The mountain terrain is literally fixed. The mountain gains in beauty; those who live on its slopes gain in security.
After the operation of the turfing of the mountains, the second diorama which represents the torrent of Riou-Bourdoux, in the Ubaye valley
the Ubaye valley (Basses-Alpes), will give us a very clear idea of the work carried out by the Forestry Administration to dam and reduce the devastating torrents in our mountainous countries.
The Riou-Bourdoux torrent is the most formidable of all those currently active in the French Alps. It starts at an average altitude of 2,800 metres, receives numerous tributaries along the way and carries with it a prodigious quantity of dejecta, the residue of the mountain, to which the name of lava has been rightly applied. Its destructive action is enormous. It was, at least, because since 1875 everything has changed significantly. Where the crumbly ground offered an easy prey to the torrent, a forest was created from scratch and the ground became solid. Then a series of dams were built, one of which, the most important, clarifies the waters of the torrent by stopping the materials they carry. The bed of the torrent was determined by methodical cleaning. Wherever the land could be reforested and grassed over, the operation was carried out. The second diorama shows us these various works.
The third and last diorama shows us the Bourget torrent, also in the Ubaye valley, and which is one of the first to which the preventive works we have just briefly enumerated were applied.
The origin of this torrent is at an altitude of 2957 metres. The first works on it date from 1870. All the stable land in its basin has been reforested and is now covered by a forest of more than 400 hectares, which is becoming increasingly thicker. The settled land was fixed by a series of so-called correction works. In short, the torrent is now only a stream whose work is only beneficial.
Unfortunately, we do not have enough space to expand on the question of reforestation of our mountains, a complex and vital question, eminently interesting and full of surprises, to which we ask the attention of our readers.
© L'Exposition Universelle de 1889 - Louis Rousselet - 1890