REMOVE

1. trees
2. rock
3. tools
4. sky
5. freight cars
6. farming

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. branches (plant component … (1)
4. bushes (1)
5. chairs (furniture forms) (1)

More 

WHERE

1. Ensenada, Baja California … (1)

WHO

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

WHEN

1. 1949 (1)