Hello, 
Thank you for adding all those details to the city center! Please make sure to tag treerow lines with natural=tree_row. Natural=tree is only used for single nodes, representing individual trees. So in this case, the nodes of the line should be tagged natural=tree, while the line itself should have natural=tree_row. I already fixed it here and near Dronning Louises Bro, where you added a tree row a few days ago, so just a heads up for future edits. 

Thanks and happy mapping! 