4.20 of the Christchurch City Council Tree Policy states
Request for removal of
tree(s) will be considered for health reasons where there is confirmation from
either the applicant's medical practitioner, a clinical immunologist or the
medical officer of health confirming that the tree(s) is/are the sole cause of
the applicant's condition and that removal of the tree(s) is the sole most
practicable solution to significantly improving the applicant(s) condition.