  We propose a simple method to construct integral periodic mask and
corresponding scaling step functions that generate non-Haar orthogonal MRA on
the local field $ F^{(s)}$ of positive characteristic $p$. To construct this
mask we use two new ideas. First, we consider local field as vector space over
the finite field $GF(p^s)$. Second, we construct scaling function by arbitrary
tree that has $p^s$ vertices. By fixed prime number $p$ there exist
$p^{s(p^s-2)}$ such trees.
