N.H. Rev. Stat. Ann. § 231:147

It shall be unlawful to cut, destroy, injure, deface, or break any public shade or ornamental tree; or to affix to any such tree a play bill, picture, announcement, notice, advertisement, political or otherwise, or other device or thing, or to paint or mark such tree, except for the purpose of protecting it and under a written permit from the tree warden.