I'm wondering if people wore this, I mean it's big!
This is a robe made by an Ainu artist, in the region that is now Northern Japan. And yes, It was a worn item, despite being particularly large.
More decorative attush (robes made of elm bark) would have been used for ceremonial occasions, while more simply decorated ones would be worn as everyday items.
What was the advantage of using elm bark to form yarn over more common forms of textile production?
Elm bark was one of the materials that was readily available for fiber production in Ainu Moshir (now Hokkaido and the smaller islands north of Japan). It was also a material that held up well to cold and wet weather.
The elm bark robe that you see here has cotton detailing, dyed with indigo. Both the cotton and the indigo would have been imported, probably from Honshu, or mainland Japan.
That makes a lot of sense. The northern islands have more extreme weather!
Exactly. This type of coat was also adopted by some culturally Japanese fisherman for the same reason, although garments like this became far more scarce after the 1876, when the Japanese government banned Ainu personal adornments.
Do you have to keep these at a certain temperature to maintain the clothes?
In general, keeping clothing cool and dry will help it to stay preserved for longer. We are most conscious, however of light, as textiles like these can fade over time. That is why the lights in the areas where you see textile work are kept relatively dark.
The particular garment you're looking at right now is made of elm bark, and was made to withstand cold wet weather by the Ainu people in Northern Japan. So it is surprisingly resilient, but we still keep it carefully preserved.