The Culler-Vogtmann Outer space $\text{CV}_n$ is an analogue of Teichmuller space for the group $\text{Out}(F_n)$.

Is there any notion of a geodesic path in $\text{CV}_n$? Are there different competing definitions of geodesic?

If so, what would be a simple example of a geodesic path vs. a non-geodesic one, say on $\text{CV}_2$?