The permutation routing problem is studied for trees under the matching model. By introducing a novel and useful (so-called) caterpillar tree partition, we prove that any permutation on an n-node tree (and thus graph) can be routed in 3 2 n + O(log n) steps. This answers an open problem of Alon, Chung, and Graham [SIAM J. Discrete Math., 7 (1994), pp. 516–530]. Key words. matching routing, off-line algorithms, trees AMS subject classifications. 05C, 68M, 68R PII. S0895480197323159