In periodic gossip schemes, the calls are periodically repeated accord
ing to a proper coloring of the edges of the underlying graph with int
egers 1, 2,..., c. One period consists of c consecutive rounds 1, ...,
c each containing time-parallel bidirectional calls on all edges with
the same color. The problem is to design colorings which minimize the
number of periods until gossiping is completed. We present an algorit
hm yielding ''reasonable'' colorings for trees, and discuss cases wher
e it produces an optimal coloring. For these cases, the periodic gossi
p time, i.e. the minimum number of periods can be computed from the al
gorithm.