What type of tree was the tree of knowledge of good and evil?

A:The Tree of Knowledge of Good and Evil was of course mythical. It was a common motif among the West Semitic nations of the ancient Near East. There are two views on the effect of eating its fruit:

1. The person eating the fruit will understand the difference between good and evil, like a god.
2. Since everything in the world is either good or evil (a rather simplistic view), the person eating the fruit will know everything there is to be known.

Another Answer:

The Bible is not specific as to its 'type' only that it was appealing to the human eye and bore edible fruit - so generally speaking it was a fruit tree.

More importantly, as God gave the first two humans full run of the Garden of Paradise, which was in an ideal climate, He pointed out this tree to give them as a choice to either follow Him and His ways as He was teaching them assumingly or do their will/way which He would need to assist them with initially (fire, agriculture, etc) - free will in other Words as He did not create automatons. Obviously they choose wrongly but God already knew they would and had a Plan of Salvation in place for all mankind.