My question is since the inverted Vee elements are going to have about 20 ...maybe 25 degrees angle to the ground...will this log periodic antenna be vertically polarized?
Do you really mean 20 degrees to the ground, or 20 degrees to vertical?
20 degrees to the ground is close to flat, and should work well. It will mean
that the wires extend well beyond the 20' cleared path, however.
20 degrees to vertical is a very steep angle. Not only is that going to mess
up the feedpoint impedance of the Log Periodic, but it won't be very efficient,
either, because much of the radiation from one side of the dipole will be
cancelled out by that from the other side. I think it is unlikely to work well.
No, that doesn't make it vertically polarized. Both wires will have horizontal
and vertical components. If you look at the directions of the currents on
each half of an element the horizontal components will be in phase and the
vertical ones out of phase (and will mostly cancel each other). That leaves
you with primarily horizontally polarized radiation.