Aims: This study aimed at disentangling the respective influence of species, environment, root size and root type in tree root architecture. Method: The root system of 106 adult trees from ten species was carefully extracted from French dikes. Root length and proximal diameter, length and diameter of root segments and branch insertion diameter were measured. Root branching and tapering rates, segment taper, classical (P) and new architectural parameters related to branching patterns were computed. Results: Two contrasting root types called "running" (R) and "short" (S), were identified from growth and architectural parameters. Compared to S roots, R roots were longer for an equivalent proximal diameter and singled out with lower tapering rate, branching rate and segment taper and with smaller branches. Their main axis lost less in diameter at branching point for branches of the same size. Tree species had little influence on these architectural parameters. The effect of soil material (coarse vs fine) was significant mainly on root size, on branching rate in fine material, and only secondarily on some branching patterns for running roots and on segment taper. The new architectural parameters describe branching patterns more accurately than classical ones. Conclusion: This study provides an original insight in tree root architectural analysis, proposing a new root typology and innovative parameters for the description and modelling of root architecture.