The aim of the LIFE ELIA project was to transform the forest rights-of-way of high-voltage power lines into ecological corridors. One of the actions is the (re)creation of tiered edges using indigenous secondary species. Conclusive experiments have been carried out to produce the necessary plans, given the unavailability of certain secondary species in nurseries and the desire to reduce planting costs. An efficient method of propagating these plants has been developed, using seeds of controlled origin.