REMOVE

1. plants
2. winter
3. clouds
4. forests (plant communities)

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. farms (1)
4. fields (land) (1)

More 

WHERE

1. Westminster, Maryland (1)

WHO

1. Campbell, Sandra L. Still (1)
2. Sandra L. Still Campbell; … (1)

WHEN

1. 1963 (1)
2. 1963 - 1964 (1)
3. 1964 (1)