Albert Barnes Commentary 1 Samuel 22:6

"And Saul heard that David was discovered, and the men that were with him: now Saul was sitting in Gibeah, under the tamarisk-tree in Ramah, with his spear in his hand, and all his servants were standing about him." — 1 Samuel 22:6 (ASV)

Under a tree in Ramah - Rather, it was “under the tamarisk-tree on the high place,” where he always held such meetings. It was a kind of parliament in the open air, and all his tribesmen gathered around him. (Compare to Judges 4:5.)