Pinus sylvestris vs pine tree

Pinus sylvestris and pine tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pinus sylvestris	Yes	No	No	No
pine tree	Yes	No	No	No

As nouns, pine tree is a hypernym of Pinus sylvestris; that is, pine tree is a word with a broader meaning than Pinus sylvestris:

Pinus sylvestris: medium large two-needled pine of northern Europe and Asia having flaking red-brown bark
pine tree: a coniferous tree

Other hypernyms of Pinus sylvestris include pine, true pine.

Pinus sylvestris (noun)	pine tree (noun)
medium large two-needled pine of northern Europe and Asia having flaking red-brown bark	a coniferous tree