https://thenextweb.com/science/2021/02/15/scientists-making-transparant-wood-replacing-glass-syndication/

Wood is an ancient material humans have been using for millions of years, for the construction of housing, ships, and as a source of fuel for burning. It’s also a renewable source, and one way to capture excess carbon dioxide from the Earth’s atmosphere. Today, the main component of wood – cellulose – is produced annually at 20 times the volume of steel.

One thing you wouldn’t use wood for is making windows. Instead, we rely on glass and plastic, which are transparent and, when toughened, can give structural support. But buildings lose a lot of heat through glass, and while light can bring some heat through the material, it’s not a good insulator. This is why we need double glazing. Wood, on the other hand, is highly insulating but it’s not transparent. Usually.