REMOVE

1. trees
2. ladders
3. barns
4. buildings (structures)

WHAT

1. black-and-white film (1)
2. cornstalk (1)
3. exterior views (1)
4. farms (1)
5. fields (land) (1)
6. forests (plant communitie … (1)
7. freight cars (1)
8. landscapes (representatio … (1)
9. plants (1)
10. railroads (1)
11. rails (transit system ele … (1)
12. rubbish (1)
13. sky (1)
14. soil (1)
15. trains (vehicle groupings … (1)
16. trucks (1)
17. utility poles (1)
18. Visual Works (hierarchy n … (1)
19. wheels (components) (1)
20. wrecks (sites) (1)

WHERE

1. New Windsor, Maryland (1)

WHO

1. Campbell, Sandra L. Still (1)
2. Clyfford Still; Still, Cl … (1)
3. Sandra L. Still Campbell; … (1)
4. Still, Clyfford (1)

More 

WHEN

1. 1969 (1)