Hello Mr. Karoubas and fellow friends.
Your post made me addicted (in a good way I hope) to this site.
After reading it, I wandered around in my town and found some candidate fruit and non fruit trees to save seeds from.
I got Almonds, Capers (grow on its own everywhere), Medit. Redbud, Prosopis Farcta, Caesalpinia Gilliesii and Honey Locust (the latter four are N fixating as far as I found).
I sowed multiple seeds of different trees in many locations ( a hilltop, almost barren public park, abandoned -or not- lots), before a heavy rain two days ago, and I hope most of them will establish well in our climate (14" of precipitation, November through April or May), I will go with figs and pomegranates next year I hope.
Some plants that thrive on neglect are Oleander (native?) and Chinaberry (non native) but I didn't bother with them because both are poisonous to humans and livestock and the latter is allelopathic, should I use them?
My town is located in north of Syria.