I asked Anas (Allah be pleased with him) whether Messenger of Allah ﷺ had declared Medina as sacred. He said: Yes, it is sacred, so its tree is not to be cut; and he who did that let the curse of Allah and that of the angels and of all people be upon him.
سَأَلْتُ أَنَسًا أَحَرَّمَ رَسُولُ اللَّهِ ﷺ الْمَدِينَةَ قَالَ نَعَمْ هِيَ حَرَامٌ لاَ يُخْتَلَى خَلاَهَا فَمَنْ فَعَلَ ذَلِكَ فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ