acacia: the hardy desert acacia tree and, above all, the durable timber cut from it
This word names a single thing seen from two angles: the acacia tree that grows wild in the dry country south and east of the land, and the tough, close-grained wood that tree yields. Nearly every appearance is about the wood, because acacia was the one good building timber a people camped in the wilderness could actually find. The tabernacle and its furniture were framed almost entirely from it.
The wood mattered because of what it was: dense, resistant to rot and insects, and available in the desert where cedar and cypress were not. Its senses hold together simply. When the text speaks of the standing tree it means the plant; when it speaks of the material worked by craftsmen it means the timber. There is no shift in the underlying idea, only in whether the tree is growing or has been cut and shaped.
The living tree appears just once, in a promise that God will plant trees in the desert, where acacia sits in a list of species alongside cedar, myrtle, and cypress. Everywhere else the wood is being measured, joined, and overlaid with gold to build the place where Israel met God.