I saw it a while back and was kinda looking for it again.. very interesting.
There was some shepherd, in some european country who always took oak acorns with him, and would plant them every day while tending his flock.. It was the same kind of land.. arid, scrub brush, pretty worthless stuff... then a LONG time later, the acorns started to grow and provide shade, and a similar thing happened, everything became lush, springs appeared, and it became a beautiful place... I'll try and figure out who that was and find a reference.