Last year I traveled to Paris. In one of the oldest parks in Paris was one of the oldest Sycamore trees in the city. This sign shows that all that history and current science has got it wrong about root growth. They need to read my book Roots Demystified. If they read it, they would understand that all tree roots are at least 1/2 times wider than the canopy (dripline). In a sandy soil the roots can grow three to seven times wider than the dripline.
I think the last paragraph talks about the root system and nutrients, but I can not read French. Maybe someone reading this blog could translate it for me and others. (Click on the image to get a full screen view to make it easier to read.)
NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert