The fig tree cursing narrative is found in Matthew's and Mark's gospels. Mark's account varies in sequence from Matthew's account as it is written in two sections: First, after departing the temple, Jesus sees the fig tree in leaf, but no fruit found, followed by cursing [Mark 11:12-14]. Second, after departing from temple (Where Jesus drives out money changers), Jesus and disciples find same fig tree withered, then Jesus teaches lesson on prayer [Mark 11:20-25]. These two sections provided an acted out prophetic lesson to Christ's disciples as they were also spoken in parabolic forms also. Before getting to the heart of the answer, we must examine a few other linking passages.
A few years earlier John the Baptist who came in the spirit of Elijah, foretold Israel's demise with these words:
Mat 3:8 Bear fruit in keeping with repentance.
Mat 3:9 And do not presume to say to yourselves, 'We have Abraham as our father,' for I tell you, God is able from these stones to raise up children for Abraham.
Mat 3:10 Even now the axe is laid to the root of the trees. Every tree therefore that does not bear good fruit is cut down and thrown into the fire.
It would seem fitting that after the cursed tree of Mark 11 had withered its only value laid in being burned.
Parable of the barren fig tree.
Luk 13:6 And he told this parable: "A man had a fig tree planted in his vineyard, and he came seeking fruit on it and found none.
Luk 13:7 And he said to the vinedresser, 'Look, for three years now I have come seeking fruit on this fig tree, and I find none. Cut it down. Why should it use up the ground?'
Luk 13:8 And he answered him, 'Sir, let it alone this year also, until I dig around it and put on manure.
Luk 13:9 Then if it should bear fruit next year, well and good; but if not, you can cut it down.'"
These parables unfolds three years of a planter's (The father's) frustration after finding no fruit (Repentance). The vine dresser (The Son) appeals to need of further cultivation (ministry of Holy Spirit), and if not effective, tree is to be burned (wrath of God). It's no coincidence that the three years mentioned summed up Christ's earthly ministry.
Answer:
In his work New Testament Documents: Are They Reliable scholar F.F. Bruce points out that given the time frame of Mark 11, being late March/early April, it was not uncommon for people to seek a knob like fruit called taqsh from the broad leaf displaying yet too early for fig producing fig tree.
NT Doc: Are They Reliable F.F. Bruce. Ch 5:
The other miracle is the cursing of the barren fig tree (Mk. xi. '2 ff.), a stumblingblock to many. They feel
that it is unlike Jesus, and so someone must have misunderstood what actually happened, or turned a
spoken parable into an acted miracle, or something like that. Some, on the other hand, welcome the story
because it shows that Jesus was human enough to get unreasonably annoyed on occasion. It appears,
however, that a closer acquaintance with fig trees would have prevented such misunderstandings. 'The
time of figs was not yet,' says Mark, for it was just before Passover, about six weeks before the fully
formed fig appears. The fact that Mark adds these words shows that he knew what he was talking about.
When the fig leaves appear about the end of March they are accompanied by a crop of small knobs,
called taqsh by the Arabs, a sort of forerunner of the real figs. These taqsh are eaten by peasants and
others when hungry. They drop off before the real fig is formed. But if the leaves appear unaccompanied
by taqsh, there will be no figs that year. So it was evident to our Lord, when He turned aside to see if
there were any of these taqsh on the fig tree to assuage His hunger for the time being, that the absence of
the taqsh meant that there would be no figs when the time for figs came. For all its fair show of foliage, it
was a fruitless and hopeless tree.'
According to Bruce, it was not actual figs Jesus sought, it was the taqsh, an edible sign that the tree would in fact bear fruit that season. Mark wisely inserted the note on figs not yet being in season. The people of the far east would have immediately known of the taqsh Jesus looked for.
Though there is a puzzling element even given this information and linking parables. Jesus says in Mark 11:14: "May no one ever eat fruit from you again". These word may be summed up in the words of the JFB Commentary notes on this verse: Those words did not make the tree barren, but sealed it up in its own barrenness. In other words, the cursed fig tree was the emblem of the unrepentant Jewish nation. And because they knew not the time of their Messiah's visitation it was impossible for them to bear fruit, or if it did its fruit would be bad.
If room would allow I'd show why Jesus cleansed the temple, and how Jesus' lesson on prayer, and his reference to the mountain being thrown into the sea relates to the symbolism of Revelation 8:8, where a huge mountain ablaze is cast into the sea. It directly relates to why Jesus cursed the fig tree and the subsequent burning of Jerusalem in AD 70.