Concurrent with the spread of exotic species and the increase in average annual temperatures, there is also a change in spontaneous vegetation, which is undergoing a process of natural adaptation. This phenomenon is defined as laurelization, which is influencing the composition of current forest vegetation. Many species with evergreen leaves, such as laurel, privet, ivy, holly, some palms (Trachycarpus fortunei), and the Japanese loquat—both native and exotic—are gaining ground in vegetation belts (generally characterized by a “colder” climate) that were previously dominated by chestnut groves in hilly areas. These evergreen plants are typical of spontaneous forests mainly located in the Azores and western Canary Islands, known as “subtropical-temperate laurel forests,” from which the term laurelization originates. This noticeable expansion, observable in the understories of pre-Alpine areas near lakes, aligns with what occurs in vegetation found in warmer climate zones, as confirmed by numerous scientific studies published in recent years. Evergreen plants, due to rising temperatures, prove to be more competitive, as they can fully exploit mild winter days and mid-season periods compared to vegetation forms with a cycle marked by a dormant period involving complete loss of foliage. This drives their spread to increasingly higher altitudes. The altitudinal range affected by the laurelization process of broadleaf forests seems, for now, to be limited to elevations up to 500 meters and distances greater than about 200 meters from inhabited areas, such as residential gardens from which they spread.

In the past century and the one before, the gardens of grand villas and botanical gardens hosted rare specimens for study, ornamentation, or collection purposes, brought from faraway lands through travels. Today, however, it is the gardens of homes and villas that host a wide variety of ornamental species. These species become sources of exotic plants that, finding suitable conditions in the woods, develop and reproduce naturally. Among the key factors driving the uncontrolled spread of these species, reproductive capacity stands out. When a plant reproduces sexually (flowering and fruiting) or vegetatively (cuttings, root suckers, etc.), two scenarios may unfold: either the exotic plants naturalize or they become invasive. In the first case, the new vegetation does not cover extensive areas and tends to expand gradually around the original generations. In the case of invasive species, however, plants can quickly cover large areas, either by dispersing large quantities of seeds or by vegetative propagation. For instance, following coppicing, root suckers sprout prolifically, each forming a new plant.
Moreover, these plants often exhibit a paradoxical ability to adapt and tolerate a wide range of environmental conditions (moisture, light, nutrients, temperature, soil). This adaptability enables their development even in degraded areas. The primary pathways for the expansion of these plants are boundary areas where the forest is sparse, such as along the Oliera Trail, where the presence of neophyte species is noticeable.