Weirwood
Weir trees resemble oaks but have leaves that are
brown (with a silver sheen) on their uppers and velvety black
beneath. If undisturbed, weir trees grow into huge, many-branched
forest giants. Weirwood won't ignite in normal (nonmagical)
fire and is resilient and durable. It's favored in the
making of musical instruments because of the unmistakable
warm, clear tone it imparts.
Weirwood can be used as a replacement for oak or holly in any
spell. It grows throughout Faerun but is very rare. Most trees are
now found deep in large forests and actively protected by dryads,
treants, druids, and rangers.