Tough Broadleaf Tree With Year-Round Leaf Cover

Puzzle 17 of Vienna Hard Pack

Question is: Tough Broadleaf Tree With Year-Round Leaf Cover

and the answer is: HORNBEAM

Word Meaning:

HORNBEAM — A tree of the genus Carpinus, having a smooth gray bark and a ridged trunk, the wood being white and very hard, common along the banks of streams in the United States.

Definitions from Wiktionary.