Flea and tick collars do not work well enough on long-haired dogs to be useful. Wildlife can be very dangerous to your dog. Deer can kick a dog to death. Bears can maul a dog to death. Raccoons will tear a dog up and can have rabies.
Rattlesnakes can inject poisonous venom.
Bobcats can kill a dog. Mountain Lions prey on dogs. Rodents can carry a number of diseases. All of the above carry parasites ranging from fleas and ticks to worms of various types. These are good reasons not to let your dog off leash.