Beech Hedge.

hello it shouldn't harm the hedge to cut the stems back I trim 100 yards of beech and hornbeam hedge every September when it gets wider than the hedge cutter blade (30 inch)it gets cut back to within 9 inches of the trunk one year then the other the following year it slows it down but comes back denser I don't cut if its frosty if frost is forecast I finish cutting about 3pm to give the cut ends time to dry  I was taught a little rhyme for cutting beech hedges which seems to work cut in may you'll cut for ever and a day cut in August and September it'll be a year and a day also remember that there's a bird nesting season April to September cutting between these months its recommended to do a nesting assessment    jezza