REMOVE

1. hats
2. trees
3. wood products
4. barns

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. exterior views (1)
4. farmers (1)

More 

WHERE

1. Alberta, Canada (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1940 (1)
2. 1940 September 8 (1)