  We give an explicit relation between the slope of the trajectory of a
semigroup of holomorphic functions and the harmonic measure of the associated
planar domain ${\varOmega}$. We use this to construct a semigroup whose slope
is an arbitrary interval in $ [{\pi}/2,-{\pi}/2] $. The same method is used for
the slope of a backward trajectory approaching a super-repulsive fixed point.
