  We introduce a class of automorphisms of rooted $d$-regular trees arising
from affine actions on their boundaries viewed as infinite dimensional vector
spaces. This class includes, in particular, many examples of self-similar
realizations of lamplighter groups. We show that for a regular binary tree this
class coincides with the normalizer of the group of all spherically homogeneous
automorphisms of this tree: automorphisms whose states coincide at all vertices
of each level. We study in detail a nontrivial example of an automaton group
that contains an index two subgroup with elements from this class and show that
it is isomorphic to the index 2 extension of the rank 2 lamplighter group
$\mathbb Z_2^2\wr\mathbb Z$.
