2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/105003A spanning tree T in a finite planar connected graph G determines a dual spanning tree T* in the dual graph G such that T and T* do not intersect. We show that it is not always possible to find T in G, such that the diameters of T and T* are both within a uniform multiplicative constant (independent of G) of the diameters of their ambient graphs.7 pages, 3 figuresCombinatoricsGroup Theory05C10, 05C12, 20F06, 57M15text