Answer
Acacia wood is often mentioned in reference to objects used in the construction of the tabernacle in the book of Exodus. Of greatest importance is its use in the construction of the Ark of the Covenant. Why acacia wood? Does it have any special significance?
From a practical standpoint, acacia trees would have been one of the only types of trees growing in the wilderness regions traveled by Israel. In addition, acacia wood is dense and extremely strong, making it a great option for any type of wooden construction.
One researcher has noted, “This wood is resistant to decay because the tree deposits in the heartwood many waste substances which are preservatives and render the wood unpalatable to insects making the wood dense and difficult to be penetrated by water and other decay agents.” (Source: http://ww2.odu.edu/~lmusselm/plant/bible/acacia.php)
During the construction of the tabernacle, acacia wood was one material available to the Israelites. Exodus 35:24 says, “Everyone who had acacia wood for any part of the work brought it.” Acacia wood was used for the poles of the ark, the ark itself, and many parts of the tabernacle. In fact, acacia wood is the only type of wood used in construction of aspects of the tabernacle.
The use of acacia wood resulted in materials that endured for a long time. The tabernacle was used for the next four hundred years, eventually finding a resting place within the temple in Jerusalem constructed during the reign of Solomon. The ark remained a crucial part of Jewish worship until the destruction of the temple by the Babylonians centuries later.
Some may seek to attach a spiritual power to acacia, but the Bible makes no such claims. Instead, it appears that acacia was the main tree available during the wilderness journey, and its density and strength made it ideal for a structure that would endure for generations.