In my book Kolibear is right, a strut supports load in compression and a tie in tension. So methinks they're struts under the Me/Bf 109's tail and ties under a Cessna 150's wing!
In my early training, I was taught that, in 1g flight, the load on tailplanes is not vertically upwards but vertically downwards. The centre of gravity (cg) of aircraft with tailplanes (rather than canards) is forward of the centre of lift (CoL) and thus needs a tailplane download to balance it out and give stability. Control inputs through the elevators can change that. One would expect the critical load to be that of pitching the aircraft nose up; so a combination of the load to balance the cg and the control load to pitch the aircraft - that's a big tailplane download and thus the 'struts' are in compression.
Aircraft with 'neutral stability' - mostly the new-ish highly manoeuvrable fighters - have cg and CoL roughly co-incident and thus very small tailplane downloads but are horribly unstable to fly and really only work with fly-by-wire.
That does not mean all FbW aircraft are like that; civil FbW airliners all have good natural stability (cg fwd of CoL).
Aircraft like the Airbus A310-300 and A340 have a tailplane tank and pump with a sophisticated control system which, within the constraints of a stable aircraft, allows the cg to be as far aft as possible to both minimise the trim drag from the tailplane download and reduce the induced drag from the wing since the overall lift requirement is less with a lower aerodynamic tailplane download.
Sorry if I've gone on a bit...