Evergreen or holm-oak forest is made of trees and bushes with large, perennial and hard leaves that rarely surpasses 10-meter height. Holm-oak is the dominant tree. There are two subspecies, Quercus ilex ssp. ilex with bitter acorns and long leaves and Quercus ilex ssp. ballota with sweet acorns and round shaped leaves with hairs on the back side. The holm-oak with bitter acorns is typical from humid and sub-humid maritime Mediterranean areas, whereas the holm-oak with sweet acorns is typical from continental and southern Mediterranean areas of Iberian Peninsula and northern regions of Africa.
In the district of Bages, most of holm-oaks must be considered hybrids between the two subspecies by their intermediate characters. In the south, holm-oaks closer to Quercus ilex ssp. ilex (long leaves and bitter acorns) seem to predominate. In fact, both subspecies receive the same name in Bages while they’re discriminated in other regions.
The two holm-oak subspecies make the biggest difference between the two types of evergreen oakwoods in Catalonia, Quercus ilex ssp. ballota in the so-called “carrascar” and Quercus ilex ssp. ilex in the so-called littoral holm oak forest. Littoral holm-oak forest contains more species of bushes like laurustinus (Viburnum tinus), butcher’s broom (Ruscus aculeatus) and Phillyrea latifolia and lianas like sarsaparilla (Smilax aspera) and honeysuckle (Lonicera implexa), whereas species like madder (Rubia peregrina), evergreen buckthorn (Rhamnus alaternus) and wild asparagus (Asparagus acutifolius) are common in both types of holm oak forests.
The inside of the holm oak forest, specially the littoral one, is dark, entangled and difficult to cross because the profusion of bushes and lianas, but grasses are scarce due to the lack of sunlight.
The charcoal was the most common exploitation of the holm oak forests until the middle of XX century. Charcoal keeps almost all the calorific power of the wood but it is significantly lighter. The felling cycle was more or less every 15 years. In the largest holm-oak forests, spots of black soil still trace the places where wood was slowly burnt to make charcoal. Furthermore, every individual holm oak tree consists of several trunks of similar size. The heritage of the lumberjacks remains in the present holm oak forest.
In Bages, holm oak forests only grow up in large extensions in the south, on the stony areas of intricate relief of Montserrat and Montcau and Serra de l’Obac. On the north-facing, stony slopes, there is the holm-oak forest with boxwood (Buxus sempervirens), where Quercus ilex ssp. ilex dominates and covers different species of luxuriant bushes. In rocky and sunny areas, the holm-oak forest is noticeably poorer in species; then Phillyrea latifolia, a species with leaves similar to that of the holm-oak but that belongs to the olive tree family, becomes the number one.
In the center and north of Bages, holm-oaks are quite frequent but not the holm-oak forest. Holm-oaks and oaks share the dominion of the mature forest, with a slight trend towards the oaks, mainly in areas with deep soil. Spots of holm-oak forest are found only in stony, not suitable for the agriculture areas.
Montserrat’s holm-oaks forest were on fire in 1986 and in 1994. In addition to the fire, holm oaks were also damaged by the drought in 1994 summer. The impact of this drought was much wider and it can still be recognized in the time of changing of millennium.
Once the holm-oak forest is installed, then is not easy to remove it. The evidence is found in the north face of Montserrat, where the holm-oak forest grew vigorously again after having been practically destroyed by the fire in 1986.
The first degradation’s phase of the holm-oak forest is the macchia, a community that’s still dominated by the same big bushes that are found in the holm-oak forest. The abandonment of crops in the potential area of holm-oak forest usually leads to a smaller vegetal community which is dominated by small bushes like rosemary.
[Jordi Badia and Florenci Vallès with contributions from Xavier Adot, Jordi Morató, Ramon Solà and Marc Vilarmau]