"C'mon, follow me — any more firs' years? Mind yer step, now! Firs'
years follow me!"
Slipping and stumbling, they followed Hagrid
down what seemed to be a steep, narrow path. It was so dark on either
side of them that Harry thought there must be thick trees there.
Nobody spoke much. Neville, the boy who kept losing his toad, sniffed
once or twice.
(Harry Potter and the Sorcerer's Stone)
Does ‘thick trees’ mean many trees whose trunks have big diameters; or does it mean dense forest?
Best Answer
In context it means "dense forest" -- there are many trees close together, making passage through them difficult.
I think it's more common to say "thick forest" than "thick trees", and that would also make more literal sense, as it is not the individual trees that are thick, but rather their "grouping".