You or one of your neighbors used something containing 2,4-D. It's a broadleaf (not grass) weedkiller that volatilizes easily and causes growth like that. It won't kill your tree, it will just look funny. It's a type of hormone imitator that causes extra-fast growth that collapses due to insufficient lignin production. On soft weeds it works real well. On trees it just looks like what you have. You can leave it or remove it, your choice.
