Who had a dream telling him to come to Rivendell, and what, briefly, were the dream's contents?
Boromir had the dream, and it contained a poem that included mention of "Isildur's Bane" and the line "And the Halfling forth shall stand."
Back at you: What tree was the favorite of Quickbeam the Ent?
Hah - not entirely right. Faramir, the cool brother, had the dream over and over, but it wasn't until Boromir finally had it (or said he did) that Denethor agreed to send Boromir.
Quickbeam... er... dunno, he was hasty and he had a long poem about some trees he once knew.