Barking, growling and howling are vocalizations and can all be stopped with verbal commands.  All three vocalizations are not allowed inside the dog park. Of course their will be times when your dog will bark, growl and maybe even howl while visiting the dog park. These behaviors are natural after all.  However, while in the park, even when no danger seems to be present, it is best to curb the behavior sternly and consistently. By discouraging it when it does occur, we are able to modify the dogs behavior in that moment, preventing other dogs from joining in and keeping the situation from escalating.