The terrain
From the sea to the summit of the volcano is thirty kilometres. In a single morning’s walk you go from a dry forest to a lava desert where almost nothing grows — and between the two, relics of primary forest. Each belt has its own species. Many exist nowhere else in the world. Some can be counted on one hand. What I teach you is how to read that scale.
Réunion, the marvellous island with more than a hundred microclimates…
Office national des forêts, Réunion regional directorate.
An endemic species exists on this territory and nowhere else. A young volcanic island isolated in the Indian Ocean produces many of them — and loses them fast. The Tuit-tuit, a bird of La Roche Écrite, is among the most threatened passerines in the world. Knowing that changes the way you walk.
Belt one
0 – 1,000 m · 17.5 to 24 °C
At this altitude the same band carries two forests with nothing in common. To the west, in the lee, the semi-dry forest: few epiphytes, ground that burns fast, and trees some of which can still be counted on one hand. To the south-east, into the wind, the bois de couleur des bas forest: tall trees, a carpet of ferns up to your knees, epiphytes on every branch. What separates them is not altitude, it is rain.
Belt two
1,000 – 2,000 m · 11 to 17 °C
The Bébour-Bélouve forests still shelter relics of primary forest, within a massif where some plots are also managed for silviculture, notably of the mountain acacia. Tree ferns rise to head height, mountain acacias twist above the path, and the humidity builds a world of mosses seen nowhere else. It is where you meet the most species in a single day.
Belt three
above 2,000 m · 11 to 5 °C
Ericoid thicket
Piton de la Fournaise is one of the most active volcanoes on Earth, and one of the few where you walk on lava flows younger than you are. It is where you read the colonisation of bare ground: nothing at first, then lichens, then the first pioneer plants taking hold in the rock.
