There are two main references to the 'baka' in the Old Testament and they both recount the same event.

It was an attack by the Philistines along the Valley of Rephaim, a valley which led up to Jerusalem: "When the Philistines heard that David had been anointed king over Israel, they went up in full force to search for him, but David heard about it and went down to the stronghold. Now the Philistines had come and spread out in the Valley of Rephaim; so David inquired of the Lord, 'Shall I go and attack the Philistines? Will you hand them over to me?' The Lord answered him, 'Go, for I will surely hand the Philistines over to you.' So David went to Baal Perazim, and there he defeated them...Once more the Philistines came up and spread out in the Valley of Rephaim; so David inquired of the Lord, and he answered, 'Do not go straight up, but circle around behind them and attack them in front of the Baka (balsam) trees. As soon as you hear the sound of marching in the tops of the Baka (balsam) trees, move quickly, because that will mean the Lord has...”

Pistacia lentiscus

THE BAKA?: Pistacia lentiscus (mastic) flowers. PICTURE: KoS/public domain.

There is also possibly another reference to the 'baka' where it is used as the name of a valley (Psalm 84:6).

The 'baka' is translated as ‘mulberry’ in the KJV and as ‘balsam’ in the NIV, so what is the baka tree? The Arabic word 'baca' is, according to Arabic writings, identified with the balsam tree (Balsamodendron opobalsamum). While this tree can be found growing near Mecca, no such tree is known in Israel. So the balsam tree is not likely to be the 'baka'.

The Hebrew word 'baka' is closely related to 'beki' which is translated as ‘weeping’. This name may have been given to a tree or plant that exudes a lot of gum. The prickly acacia, also called gum Arabic tree (Acacia nilotica), is one such plant, and the other is the mastic (Pistacia lentiscus). In addition it has been claimed that "a sad weeping noise...occurs when the mastic is walked on and its branches are broken".

If the 'baka' is the mulberry, as per the KJV, then it is probably the black mulberry (Morus nigra), which is cultivated all over Israel. The black mulberry has edible fruit, which has a strong flavour. However there is a question as to whether it was found in Israel in Old Testament times, because it was possibly introduced much later. Originally it came from Persia on the shores of the Black Sea. It is a medium-sized deciduous and dioecious tree.

So the more likely candidates for the baka are the Acacia nilotica and the Pistacia lentiscus.

The prickly acacia (Acacia nilotica) is a fast growing small shrub or tree, which grows to about 10 metres in height. However, this plant no longer exists in the wild in Israel today, and it is hard to determine when it disappeared from the country. 

The mastic (Pistacia lentiscus) produces gum which is extracted from this small evergreen tree. This gum has been identified as the source of balm.

The Pistacia lentiscus is more the size of a shrub than a tree, growing to no more than four metres in height (sometimes only up to a metre). It has a dense evergreen growth, and its leaves might indeed make a noise, just as it happened when the Philistine forces made their way through them, as per II Samuel 5:17-25.

Excerpt From Alvin Johnson's iBook Biblical Flora, 2017. The book is available for free download on iTunes.