Canarian flora. Vegetation floors. Mesocanary floor. Flora and vegetation of the Canary Islands

Zone mesocanaran

The mesocanario zone, also known as the Mesocanarian montane zone or the pine forest zone, extends above the laurel forest or fayal-heathland zones on the northern slopes, and above the upper limit of the cardonal-tabaibal zone on the southern and south-western slopes, occupying a band at altitudes ranging from approximately 800 to 2,000 metres. In this zone, the air becomes drier, sunshine levels increase and diurnal and seasonal temperatures are less uniform; there may be some frosts and snowfall during the winter, and the temperature contrasts between day and night are also more pronounced. These are the climatic conditions in which the Canary Island pine (Pinus canariensis) forests thrive; this is the dominant species in this zone, occupying large, dense areas known as pine forests.
This altitudinal distribution of the Canarian pine forest determines its presence on the various islands of our archipelago, with the most extensive pine forests being found on Tenerife, La Palma, El Hierro and Gran Canaria, whilst La Gomera has only scattered patches, and Lanzarote and Fuerteventura have no such forests at all, as their most mountainous areas do not exceed 800 metres in height.

     The Canary Island pine is a hardy, large-growing species that can exceed 50 metres in height, with abundant branching and long, needle-like leaves grouped in threes in dense clusters. Their needle-like shape minimises water loss during dry periods and protects them from frost in winter, enabling them to withstand very low temperatures for long periods. It also has a very powerful and active root system, colonising and forming soil in terrain as challenging as that of recent volcanic rock.
     The Canary Island pine’s frugality and resistance to drought and cold are complemented by its ability to withstand fire; it appears to have adapted to the constant threat of fire, with wildfires now an integral part of the pine forest’s very fabric, as fire releases the minerals that remain partially trapped in the pine needles and the wood that falls onto the forest floor, whilst the tree withstands the heat well thanks to the thick, corky bark covering its trunk. Furthermore, it behaves as a pyrophilic species, as after fires its seeds acquire a high germination capacity, and it is capable of sprouting from stumps, which enables it to quickly regenerate its above-ground parts after being burnt.
     Furthermore, the wind patterns in this vegetation zone differ from those in the others, with winds predominantly blowing from the north-west and being dry in nature. This results in a significant selection of flora accompanying the pines, which differs markedly from that of the other zones, exhibiting specific adaptations to withstand the marked climatic differences between winter and summer, such as reduced foliage, hairy leaves, a small and sometimes stocky growth habit, and seeds with hard shells, etc.

In terms of flora, the pine forest is species-poor, partly due to the environmental characteristics typical of this vegetation zone, and partly due to the intense human activity it has endured since historical times, whether through the extensive grazing practised since the time of the indigenous peoples, or through the intensive and uncontrolled exploitation of its prized timber, which occurred particularly after the conquest of the islands, leading to the deforestation of large tracts of pine forest on the islands of Tenerife and Gran Canaria.
This has resulted in significant selection pressure on the flora associated with the pine trees, which is evident in two main ways: on the one hand, most plants have sought refuge in rugged areas of the forest to escape fire and grazing; and on the other hand, the plants that continue to grow within the pine forest are either fire-resistant or are not eaten by livestock due to their unpleasant smell or taste.

Under favourable conditions, the pine canopy spreads widely and the pine forest forms a canopy that allows little light to penetrate; the undergrowth is dim and dry in summer, and very dark and damp in winter. This, combined with the scarcity of nutrients in the soil, results in very sparse undergrowth, where only a handful of species thrive in this hostile environment. One of the most common is rockrose (Cistus symphytifolius), which colonises the ground well after fires and is very common in somewhat open pine forests. We also find various species of thyme (Miromeria spp.) and lotus (Lotus spp.), the blue echium of La Palma (Echium webbi), the chahorras (Sideritis dasygnaphalla and Sideritis oroteneriffae), wild rosalitos (Pterochepalus dumetorum and Pterocephalus porphyranthus), the palomera (Pericallis lanata), wild oregano (Bystropogon origanifolius), etc. And in the sunniest areas, the escobón (Chamacytisus proliferus) and the codeso (Adenocarpus foliolosus) are found.

In areas where there are very stable cliffs, we can find a wide variety of small plants, particularly succulent rock-dwelling species such as the so-called ‘bejeques’, ‘veroles’ or ‘pasteles de riesgo’: Aeonium spathulatum, Aeonium aureum, Aeonium aizoon, etc.
The herbaceous vegetation is equally sparse, although occasionally one comes across a flower as beautiful as the Canary Island orchid (Orchis canariensis), and in very small areas of Tenerife’s pine forests, very few specimens of the ‘pico paloma’ (Lotus berthelotii) survive; this beautiful endemic species, which is threatened with extinction, produces striking orange or reddish flowers shaped like a bird’s beak.

Orchis canariensis

When the pine forest degrades, certain dominant species emerge, namely the broom (Chamaecytisus proliferus) and the codesos (Adenocarpus viscosus and Adenocarpus foliolosus); or, in the upper zone where it meets the supracanarian vegetation zone, so-called ‘escobonales’ and ‘codesares’ then form. At lower elevations within the pine forests, the rockrose (Cistus symphytifolius) may dominate, forming, on some islands, extensive thickets known as ‘jarales’.
On north-facing slopes, where the pine forest meets fayal-brezal communities, a type of forest known as a mixed pine forest occasionally forms, in which pines intermingle with shrubby species typical of the lower zone, such as fayas (Morella faya), heathers (Erica arborea), holly (Ilex canariensis), etc.

Pinar in La Palma

Although the frequent reforestation programmes carried out in recent decades are continually transforming the vegetation landscape of the Canarian mountain peaks, particularly on the islands of Tenerife and Gran Canaria, their ongoing impact is bringing the appearance of the Canarian pine forest ever closer to what it would have been like originally, before human activity began to cause its degradation.