"For if in the case of green wood they do these things, what is to happen in the case of the dry?"

Jesus is saying this to the Women of Jerusalem during the Way of the Cross. This is the 8th Station. The "they" above are the Jews and Romans persecuting Him, but in the future it will be any person that will persecute His Body the Church.

Green Wood = Jesus

Dry Wood = His Body the Church

He has called Himself the greed wood and us the dry, for He has in Himself life and strength of the Divine nature; but we who are mere men are called the dry wood.

As though He said to the Jews, If then the Romans have so raged against Me, a fruit-bearing and ever flourishing tree, what will they not attempt against you the people, who are a dry tree, destitute of every lifegiving virtue, and bearing no fruit?

Or as if He spake to all: If I who have done no sin being called the tree of life, do not depart from the world without suffering the fire of my Passion, what torment thing ye awaits those who are barren of all fruits?

Think of Saul before his conversion and how he was agressively seeking out and burning the "dry wood" the Christians and then how Jesus said to Saul, "Saul, Saul, why are you persecuting me." To seek out and burn the "dry wood" is to in someone attack the "green wood". In Revelation 12 we see that Satan goes after the "green wood" but cannot burn it and so he then goes after the "dry wood".

On a side note, we have a cemetery in Fort Worth called Greenwood, not sure at all if it is named after Our Lord and Saviour, Jesus Christ!