It is known that for every α≥1 there is a planar triangulation in
which every ball of radius r has size Θ(rα). We prove that for
α<2 every such triangulation is quasi-isometric to a tree. The result
extends to Riemannian 2-manifolds of finite genus, and to
large-scale-simply-connected graphs. We also prove that every planar
triangulation of asymptotic dimension 1 is quasi-isometric to a tree