Was the arborcide a case of mistaken tree identity? Park Slope residents were perplexed to find the top of a lush and soaring Norway maple on Sixth Avenue between President and Carroll Streets brutally chopped off this week. The remaining tree trunk will be removed soon. “Everyone is calling us about the tree,” said the woman who answered the phone at Community Board 6 in Brooklyn. “Everyone is calling us. This has been the dilemma of the day. This is a typical Park Slope thing.”