Usually a pole is modeled as a strut—it is hinged at the base (usually ground level). However a pole can be modeled as fixed at ground level, such as a concrete pole in a concrete footing.
This chart shows a comparison of the deflections along the length of the pole using the two models. The pole is a typical class S2 10m out of ground with a stay attached at 9m and a 20kN equivalent load applied at the pole tip.
These calculations were performed using a non-linear finite element calculation method (modelling the pole in Calculix).