Looks to be some type of Chenopodium (Goosefoot/Lambsquarters). It would definitely be a weed to me, but in any case, it's not a tree.

Oh thanks. Thrawing it away then. :-)

good to have a name for those - I see those weeds all over, especially in disturbed areas

Yeah, that's a weed. Actually not a bad foliage plant, but has no redeeming flowers, so I pull them.