So there are two accounts of Leif Erikson's story: Saga of Erik the Red, and Saga of the Greenlanders.

Saga of Erik the Red says he was blown off course on his way to Greenland from Norway. He landed in Vinland, and found grapes, wheat, and maple trees. He eventually loaded the ship and went back to Greenland. He never went back, but others did.

Saga of the Greenlanders is different. Bjarni Herjólfsson was the first to see America, spotting it but not disembarking. He returned back home to tell about his discovery, and Leif decided to buy his ship so he could go back and explore. He eventually made it to Vinland, meaning Wineland because of all the grapes there. He stayed through the winter before leaving in spring or summer. Again, he didn't come back, but people such as Thorfinn Karlsefni made settlements.

They just took a bunch of resources and left, and they did have wood. They really didn’t have the need to do it. Also, part of the reason why they left is because of trouble with the natives.

I hope this answers your first question, but it’s mostly copied from a previous comment I made on a different question.