Ah, at last!!
It is Treebeard speaking about the Entwives, right before he sings his song about them.
"We believe that we may meet again in a time to come, and perhaps we shall find somewhere a land where we can live together and both be content.
But it is foreboded that that will only be when we have both lost all that we now have. And it may well be that that time is drawing near at last. For if Sauron of old destroyed the gardens, the Enemy today seems likely to wither all the woods."
I guess I have too often skipped the Ents when rereading...
