3 Calculation of the area of land
For the purposes of section 15(4)(a) of the Act, the area of the land on which trees are growing shall be calculated for the purposes of section 15(1) of the Act by reference to the area within—
(a) any physical boundary surrounding that land; or
(b) where no such boundary exists, the boundary formed by the outside of the crowns of the perimeter trees that join canopy or, which by virtue of their proximity, have the reasonable potential to join canopy on that land.