Sablewood

Sablewood is an extremely rare plant, not truly a tree, but a thick woody vine that chokes other trees to death, anchoring itself on their woody husks. The plant has no leaves or roots, absorbing what nutrients it can from its host tree. Sablewood timber is ghastly grey with tiny red streaks running along the grain. Sablewood is unlike other crafted wood as it must be carved or cut while it is still "green" for once it dries, it gains unusual properties. "Cured" sablewood emits a mild necromantic aura and can be detected with detect magic.
Properties Sablewood effectively regenerates itself. Once it has been cured, if it is damaged in any way, the wood weeps a deep red amber which fills in the damage and hardens almost immediately. This makes it extremely prized for shields as well as components for construction.
Sablewood floors imbue whatever stands upon them with necrotic energy. Undead standing on sablewood flooring gain 1d6 temporary hitpoints. These temporary hitpoints lasts only so long as they remain in contact with the floor. Undead touching this flooring also gain advantage on attack rolls and perception checks.
Sablewood Weapons Weapons that are predominantly made from wood such as bows, crossbows, clubs or spears gain the benefits of being made from sablewood.
Weapons made from sablewood regenerate damage at a rate of 1 hp per hour. Weapons made predominently of sablewood, like clubs or staves deal an extra 1 necrotic damage.