We introduce an efficient dynamical tree method that enables us, for the
first time, to explicitly demonstrate thermo-remanent magnetization memory
effect in a hierarchical energy landscape. Our simulation nicely reproduces the
nontrivial waiting-time and waiting-temperature dependences in this
non-equilibrium phenomenon. We further investigate the condensation effect, in
which a small set of micro-states dominates the thermodynamic behavior, in the
multi-layer trap model. Importantly, a structural phase transition of the tree
is shown to coincide with the onset of condensation phenomenon. Our results
underscore the importance of hierarchical structure and demonstrate the
intimate relation between glassy behavior and structure of barrier trees