International audienceThis paper addresses the following general problem of tree regular model-checking: decide whether the intersection of R*(L) and Lp is empty, where R* is the reflexive and transitive closure of a successor relation induced by a term rewriting system R, and L and Lp are both regular tree languages. We develop an automatic approximation-based technique to handle this -- undecidable in general -- problem in the case when term rewriting system rules are non left-linear
