Teide's Vegetation Zones, Sea Level to Summit

The north-east trade winds are the engine of everything that grows on Tenerife. They push moist Atlantic air against the island’s northern flank, where it rises and cools until its vapour condenses into a persistent bank of cloud. That cloud cannot climb indefinitely because a warmer, drier layer of air caps it: the temperature inversion. The result is the mar de nubes, the sea of clouds, which draws a line across the landscape that determines what lives where.

Above the inversion, from roughly 1,800 m upward, the air is arid, intensely sunny and cold at night. Ultraviolet radiation is high. This is the world of the high mountain, and it is where Teide National Park sits. Below the inversion, on the northern slopes, the cloud band sustains humid forest. On the southern slopes, in the rain shadow of the island’s ridge, the same altitude can be dry and sparsely vegetated. Altitude and aspect together, not altitude alone, shape the vegetation.

Alexander von Humboldt climbed Teide in June 1799, and the zonation he observed on the ascent became a founding observation of plant geography. The idea that vegetation organises itself into belts with altitude was not new, but Humboldt gave it a clear empirical shape on this mountain. The transect from the coast to the summit still reads as he described it.

Coastal and lowland scrub, sea level to roughly 700 m

The lowest belt is arid and open. The plants that hold the ground here are adapted to salt spray, strong sun and very little rainfall. Succulent spurges such as Euphorbia balsamifera (tabaiba dulce) and Euphorbia canariensis (cardón) are characteristic — the cardón looks like a candelabrum and can form dense stands on dry south-facing slopes. Other shrubs include Artemisia thuscula (incense), Kleinia neriifolia (verode) and various salt-tolerant grasses. On the north coast this belt is narrower and greener; on the south it can extend higher because the rain shadow keeps conditions dry well above sea level.

Thermophile woodland, roughly 200–600 m

A transitional zone that was once more extensive than it is now. The thermophile woodland, warm and dry with an open canopy, has been heavily cleared for agriculture and development. Remnants survive in ravines and on steeper slopes. Characteristic trees include the dragon tree (Dracaena draco), Canary Island date palm (Phoenix canariensis) and juniper (Juniperus turbinata). These are slow-growing, fire-sensitive species that require the shelter of a ravine or north-facing slope to persist.

Laurel forest, roughly 500–1,200 m, north slopes only

This is the cloud forest. The laurisilva is an evergreen broadleaf forest that once covered much of the Macaronesian islands and is a relict of the Tertiary period, when similar forests grew across southern Europe. On Tenerife it survives only on the humid northern slopes within the cloud band. The dominant trees are laurel relatives — Laurus novocanariensis, Persea indica, Ocotea foetens — with glossy leaves that drip moisture from the cloud all year. The understorey is dense: ferns, mosses, shrubs such as Erica arborea (tree heath) and Myrica faya (faya). Epiphytes are common. This is the richest vegetation zone on the island in terms of biomass and diversity. The southern slopes lack this belt almost entirely. Where the trade-wind cloud does not reach, the laurel forest cannot establish.

Fayal-brezal, roughly 1,000–1,500 m

Above the laurel forest, or in places where it has been degraded, a lower scrubland of tree heath (Erica arborea) and wax myrtle (Morella faya) takes over. This is the fayal-brezal. It often marks the upper edge of the cloud band, where the forest thins and the trees become shorter. On drier slopes it can replace the laurel forest entirely.

Canary pine forest, roughly 1,000–2,000 m

Pinus canariensis is the only pine native to the Canary Islands, and it is extraordinarily adaptable. It grows in the humid zone where it mixes with the laurel forest, and it continues upward into the dry zone beneath the inversion. On the southern slopes, where the laurel forest is absent, the pine belt expands to cover a wider altitudinal range.

The pine has several notable adaptations. Its needles are long and flexible, and they intercept fog effectively: water condenses on the needles and drips to the ground, a process called fog drip or horizontal rain. In a climate where true rainfall is modest, this input is significant. The tree also resprouts after fire — its thick bark protects the cambium, and new growth emerges from the trunk and branches within weeks. The pines give out at roughly 2,000 m, where the retama scrub begins.

High-mountain scrub, roughly 2,000–3,000 m

This is the zone that most visitors to the national park see. The dominant plant is Spartocytisus supranubius, the Teide broom or retama del Teide, a white-flowered shrub that grows in dense cushions on the volcanic slopes. It fixes nitrogen, which enriches the raw mineral soil and allows other species to establish. The most striking seasonal event in this zone is the flowering of Echium wildpretii, the tajinaste rojo or tower of jewels. It is a monocarpic plant: it grows as a rosette of silvery leaves for several years, then sends up a single tall spike of red flowers before dying. The spike can reach three metres. The flowering window shifts year to year with temperature and rainfall, but generally peaks in late spring to early summer.

Other plants in this zone include Descurainia bourgaeana (a yellow-flowered shrub related to mustard), Pterocephalus lasiospermus (a cushion-forming daisy relative) and Adenocarpus viscosus (sticky broom). All share adaptations to the conditions: silvery hairs or waxy coatings that reduce water loss and reflect ultraviolet radiation, and reduced leaf area with photosynthesis partly carried out in the stems.

Summit zone, above roughly 3,000 m

Above the retama scrub the ground becomes nearly bare. Loose volcanic rock, pumice and ash support very few species. The most notable is Viola cheiranthifolia, the Teide violet, which grows only on the upper slopes of the volcano and is Spain’s highest flowering plant. It is a small, compact plant with hairy leaves and pale purple flowers, adapted to the extreme ultraviolet radiation, temperature swings and thin air of the summit. The summit zone is not a place of abundance; it is a place of persistence.

Humboldt’s transect and a single coherent system

Humboldt climbed Teide in June 1799, during his stopover in Tenerife before the South American expedition. He measured altitude with a barometer, noted the plants at each level and drew a diagram of the vegetation belts. The diagram, a cross-section of the mountain with labelled zones, was later published and widely copied. It established a method: describe a mountain by its vertical sequence of vegetation, and compare that sequence across latitudes.

The transect from the coast to the summit of Teide is still one of the cleanest examples of the principle. The trade winds, the inversion and the island’s topography produce a system in which a walk of a few hours can pass through climate zones that on a continent would require travelling hundreds of kilometres. The laurel forest, the pine belt and the high-altitude scrub are not arbitrary categories — they are the direct expression of how much moisture and sunlight each elevation receives, and for how long the cloud covers it.

The best time to see the system working is on a day when the mar de nubes lies thick over the northern slopes and the summit stands clear above it. From the caldera rim you can look down on the cloud layer and understand exactly where the inversion sits, and why the vegetation changes at that line.