The carrying out on land used for the purposes of forestry, including afforestation, of development reasonably necessary for those purposes consisting of—
(a)works for the erection, extension or alteration of a building;
(b)the formation, alteration or maintenance of private ways;
(c)operations on that land, or on land held or occupied with that land, to obtain the materials required for the formation, alteration or maintenance of such ways;
(d)other operations (not including engineering or mining operations).