Let $ {\mathcal{C}} $ be a root class of groups, i.e., a class containing nontrivial groups and closed under taking subgroups and Cartesian wreath products.Let also $ P $ be a tree product of groups such that each edge subgroup of $ P $ is normal in the vertex group that includes it.The paper presents several sufficient conditions for the existence of a homomorphism from the group $ P $ onto a $ {\mathcal{C}} $ -group that is injective on all vertex groups.Some sufficient conditions for the $ {\mathcal{C}} $ -residuality of the group $ P $ are also proved.
