We study harmonic maps on
Finsler surfaces. Using Berwald frames on Finsler surfaces, we prove conformal
invariance for the energy of Finsler harmonic maps. As an application, we show that
weakly harmonic maps from a Finsler surface to a sphere 𝕊n are in fact
smooth by establishing a new Jacobi structure, generalizing the regularity
result previously known for the case of a harmonic map from a Riemannian
surface.