It is significant that this fig tree had leaves, but no fruit. Figs, unlike other trees, begin to produce their fruit before the leaves. In fact, the fruit should be ripe when the leaves are fully developed. Although this specific tree outside of Jerusalem was out of season, it was advertising that it had fruit. And when Jesus came, He saw no fruit, only leaves.
Fig leaves are a symbol of self-righteousness, a form of religion without the power thereof.
In the same way, the leaves on that fruitless fig tree were a symbol of Israel's hypocrisy and self-righteousness. Jesus cursed the tree in order to illustrate what would happen to the Jewish nation and the apostate church if they remained fruitless. This is why God tells us that when He eradicates the wicked from the universe, He destroys them root and branch. The owner of the vineyard says that for three years he has found no fruit. This makes a total of four years.