We have a lot of big sycamores... 40 foot plus, lovely trees. However several of them have had branches lopped off in the past and each now has a 'beard' where new branches have sprouted from the stumps, and in many cases these have clearly been pruned and in turn started their own new 'beards'. They look quite messy and I'd like to know if there's a way to prevent this happening? Is there perhaps some treatment I can put on the stumps when lopping them? I know you can do this when chopping a whole tree to ground level, but I don't want to kill the tree just cause removed branches to heal without re-growing.