The formation of the poplar forest here relies entirely on underground canals connecting to snowmelt water sources.
However, the construction of underground canals is complex and requires a deep understanding of groundwater paths, something the Sogdians could never do on their own.
Fortunately, Poplar Bazaar had the help of Han troops, and this matter involved a deal:
Han generals helped the Sogdians dig wells, and Sogdian merchants helped the Han chase the moon.
Anecdote · Hexi · Jade Gate Pass