Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 87, § 1

All trees within a public way or on the boundaries thereof including trees planted in accordance with the provisions of section 7 shall be public shade trees; and when it appears in any proceeding in which the ownership of or rights in a tree are material to the issue, that, from length of time or otherwise, the boundaries of the highway cannot be made certain by records or monuments, and that for that reason it is doubtful whether the tree is within the highway, it shall be taken to be within the highway and to be public property until the contrary is shown.