Translation:Yes, these trees are also from the forest.
"out of the forest" makes the trees sound AWOL - okay if you are doing walking trees from Lord of the Rings I suppose. That is they should be in the forest but they are misplaced - they are "out of the forest". If they are normal trees that have been harvested, "from the forest" sounds better.
ok, i still don't get 'is'
i thought it stands after the word (same as 'too' in english). therefore: "Igen, ezek a fák is az erdőből vannak." -> "Yes, these trees, too, come from the forest." (i.e. apart from other trees) with also that would be "Yes, also these trees come from the forest."
otoh "Yes, these trees are also from the forest." would be something like "Igen, ezek a fák az erdőből is vannak." (i.e. some of them might be from plantation, garden, park, whatever)
what am i missing?
(btw my bilingual wife says the same (so does wiktionary https://en.wiktionary.org/wiki/is#Hungarian. but wife trumps internet ;-))