That's interesting, Rockofages... I have heard that passage explained, too. I'm not exactly sure what you are saying, here... but I have heard that.
I just wanted to add that I do believe that "the fig tree" is
related to Israel, in some way, but IMO, is not exactly Israel itself (as a nation)... but is referring more specifically to "law-observant Israel" (as in, "the temple" and such)... for in another story, Jesus said, "A certain man had
a fig tree planted
IN his vineyard..."
The vineyard is Israel (according to Isaiah 5:7, and elsewhere), and
the fig tree is something He planted
IN the vineyard, i.e. something
separate ("the law" and "temple stuff" was given only to Israel).
When this resumes, Israel (at that time) will know that His Second Coming is near. That's pretty much the way I understand it, at this time... but I know that others see
"the parable of the fig tree" in Matthew 24:32-33 as representative only of
"the signs" that Jesus had just spelled out for them.
Also, when He told this other story (about the fig tree in the vineyard), He also referred to (and dealt with)
the religious leaders of that time (the time of His first coming), so this is how I see the (fig tree in)
"relation TO Israel",
but not exactly Israel itself, as a nation. Perhaps "all the trees", in Luke 21, is referring to the whole
nation of Israel? Whereas "the fig tree" itself is "law-observant Jews" (as in "temple-related" stuff, when it resumes)??? I think I've read that somewhere...

Hope I'm making sense... it's getting late.
I'd like to understand more about what you mean, though, Rockofages.

I was just reading, today, the references in Judges 9:8-15 about the trees, as you mentioned in your post (and a commentary on it... but I don't recall anything specific...)