  This paper provides a fully abstract semantics for value-passing CCS for
trees (VCCTS). The operational semantics is given both in terms of a reduction
semantics and in terms of a labelled transition semantics. The labelled
transition semantics is non-sequential, allowing more than one action occurring
simultaneously. We develop the theory of behavioral equivalence by introducing
both weak barbed congruence and weak bisimilarity. In particular, we show that
weak barbed congruence coincides with weak bisimilarity on image-finite
processes. This is the first such result for a concurrent model with tree
structures. Distributed systems can be naturally modeled by means of this
graph-based system, and some examples are given to illustrate this.
