What does this passage withing the "Passion" mean?

Question

A large crowd of people followed Jesus,
including many women who mourned and lamented him.
Jesus turned to them and said,
“Daughters of Jerusalem, do not weep for me;
weep instead for yourselves and for your children
for indeed, the days are coming when people will say,
‘Blessed are the barren,
the wombs that never bore
and the breasts that never nursed.’
At that time people will say to the mountains,
‘Fall upon us!’
and to the hills, ‘Cover us!’
for if these things are done when the wood is green
what will happen when it is dry?”

Answer 1

This speaks of the end of time when the plagues are poured out upon the earth, people will not be able to stand them. They will cry out for death to come. Jesus tell the women not to cry for him, because he already knows what will take place and who He is. The barren, those that never had children, will not have to see them die in these plagues. When he says "your children" He speaks of the future generations. it was a common Jewish practise to speak of your grandchildren, your great grandchildren etc, in that term. The last part of your question, "for if these things" I believe means that when the plagues start they continue to get worse, and if they are bad when the trees are still "green", how terrible when the trees themselves start to die.