'Tree' in the Bible

Then Absalom happened to come across David's men. Now as Absalom was riding on his mule, it went under the branches of a large oak tree. His head got caught in the oak and he was suspended in midair, while the mule he had been riding kept going.

When one of the men saw this, he reported it to Joab saying, "I saw Absalom hanging in an oak tree.

Joab replied, "I will not wait around like this for you!" He took three spears in his hand and thrust them into the middle of Absalom while he was still alive in the middle of the oak tree.