Glacial erratic

Why is there a large rock sitting in the middle of the forest? How did it get there? The glacier carried it here and deposited it as the ice sheets retreated. It is known as a glacial erratic boulder. To be fair, the erratic boulders in the glacier village of Pontresina are not as spectacular as those found in the Central Plateau, where they sit hundreds of kilometres from where they started. Much more remarkable is the Swiss stone pine and larch forest surrounding the boulder. Since stone pines and larches need quite a lot of light, the trees naturally grow in a loose, almost park-like pattern. The result is a stunning setting that is perfect for forest walks. Would you like to discover more about Swiss stone pines and larches, and why these boulders were a scientific mystery for so long?

We are standing in the middle of the Taiswald forest, a Swiss stone pine and larch forest typical of the Engadine. The gnarled Swiss stone pines and elegant larches grow with plenty of space around them, allowing a wide variety of shrubs and perennials to grow on the forest floor, such as wild bilberries and Alpine roses. The forest is flooded with light and is perfect for walking and hiking. You will encounter squirrels and various types of songbirds, some of which are tame enough to eat out of your hand. And with a bit of luck, you might even see a deer scurry past.

In many regions, Swiss stone pine-larch forests are located on steep slopes, as they only grow at altitudes of over 1700 metres above sea level. Swiss stone pines and larches form the last belt of forest before it gives way to Alpine meadows. The uniqueness of Pontresina and the Engadine is that, thanks to the exceptional altitude and the wide valley floor, this particularly picturesque type of forest can also thrive on level ground here. In lower mountain valleys, on the other hand, dark spruce trees often dominate, standing austere and closely packed.

People also love to play music here. Chamber music, to be precise. In summer, it resounds through the Taiswald forest every day from 11.00 a.m. to 12.00 p.m., weather permitting. The morning concerts by the Camerata Pontresin a are free of charge and represent a wonderful tradition that started in the summer of 1910. In bad weather, the concerts take place in the Rondo Convention and Event Centre Pontresina or in the church of San Niculò.

Why can Swiss stone pines and larches grow at higher altitudes than spruces? How do they survive temperatures of -30°C? The larch has the perfect solution; it simply sheds its most sensitive parts in autumn. Like deciduous trees, it removes the green chlorophyll from its needles, which then glow in brilliant yellows and reds, before dropping to the ground. The Swiss stone pine has a different strategy – it thickens the cell sap of its needles so that it does not freeze, even on icy winter nights. You can discover more interesting facts about Swiss stone pines and larches on the three pine paths here in the Taiswald forest.

Back to the glacial erratic boulders. The locations of these mighty boulders often became sites of legends. Not necessarily in Pontresina, but in the Central Plateau, where they remained a mysterious phenomenon for a long time. Not only are they visually striking; they are alien objects that have come from far away. Their mineralogical composition does not match the soil on which they now sit. So how did these massive rocks weighing many tonnes get to where they obviously didn't belong? Hurled through the air by giants? Spat out by volcanoes? Swept up in a flood?

At the beginning of the 19th century, nature researchers developed a more plausible explanation: at one time, glaciers covered large parts of the Alps and northern Europe. The massive foreign stones were transported by these huge ice flows and left behind when they melted. Today, this is the generally accepted ice age theory. Glacial erratics provide important contemporary evidence of just how far the glacial ice once extended. Striking and important specimens are often protected.