The Splügen Pass, where this was found, connects the Swiss Hinterrhein valley with the Valle San Giacomo in Italy and is part of the Graubunden ‘Untere Strasse’ transit route. There has been a mule track through the pass alongside the Schwarzhorag Glacier since at least Roman times which was also used by shepherds. Until a road was constructed between 1818-1823, this was the only safe way to traverse the pass (and, even then, not in winter). It’s both very exposed and dangerous terrain.
There are records of considerable amounts of customs revenue generated by mule-train traders using the pass as far back as 1396. In 1798 it was described as “the largest merchant trading route between Milan [in Italy] and Germany, mainly using horses and mules.” Between 1818 and 1823 the trail was upgraded to enable passage of freight wagons and post coaches, reaching its peak of use in the 1850s. Today, there’s a road following much of this early route but since WWII it has closed during the winter months and at other times of bad weather.
The nearest locality where bamboo naturally grows is in Uzbekistan, over 5,000 km away and then India, even further.