Problem: What are the most important words?
vines that smother trees trying to get to sunlight in the forest
Answer: forest, tree, vine

Problem: What are the most important words?
tower bridge being raised in the evening to allow a boat to pass underneath
Answer: allow, boat, pass, raise

Problem: What are the most important words?
an extreme close up of biological species eating a salmon from atop tourist attraction
Answer:
attraction, eat, salmon