Little hard to tell, but they look like lollypopped arborvitae now... you are talking about the front row and not the really tall ones behind. Right? Big ones would likely need arborist assistance - and they would probably be loath to top.

Myself having some deer ravaged specimens up to the 8' mark, I do know they'll never regenerate from the bottom up. I'm having them taken out just to keep from having to look at the remaining topknots. And I can think about replacing them with some mixed shrubs that keep their good looks with a minimum of maintenance.

i dont think there are two rows

i think they are multi leader arbs.. that splayed in some storm ..

and i think they are unsalvagable ...

whats behind...??

if they are arbs.. they are conifers.. and they are trees... and commonly called shrubs.. but they really arent .. so that was lesson one ..

and the reason i mention it.. is that 3 year rejuvenation pruning of shrubs.. will NOT work on these ... and neither will tree pruning rules ...

plan on getting rid of them ... but in the mean time.. keep in mind.. you dont have to do it all at once.. if they are providing some sight block ...

topping of trees.. is usually not favored ... google that term ...

soooo ... can you be a bit more precise on what you are trying to do.. other than just topping them ... and surely you can do that if you wnat.. they are yours ... but what i am getting at ... is that really going to solve your issue??? and i doubt it.. in the long run ...

ken

ps: we need much closer pix and w/o sun glare.. to get an id.. and you might have to get that in the conifer forum.. once we know what they are.. some issues will clarify...

Why do you think they should be reduced in height? I don't see any wires.
You might want to trim those branches that are leaning out over the yard. I'd plant something in front of them to hide the lower bare trunks.
Mike