2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/145915In this paper, in the context of the ``Dessins d'enfants'' theory, we give a combinatorial criterion for a plane tree to cover a tree from the classes of "chains" or "stars''. Besides, we discuss some applications of this result which are related to the arithmetical theory of torsion on curves.published versionAlgebraic GeometryCombinatoricstext