by Marcel Saule, botanist, author of an illustrated guide to Pyrenean flora.

Over 100 species of trees and shrubs are found in Pyrenean forests. Each species grows on slopes with different characteristics: altitude, exposure, type of soil, rainfall or cloud cover. Here we present 14 easily identifiable species which typically grow in different habitats:

| Beech |

The Beech grows at mountain level, between about 800 and 1,800 m in humid conditions with condensation forming thick fog, drizzle or rain. Though not fussy about the soil, beech trees can be badly affected by late frosts, which destroy tender young leaves and blooms. Where trees are tightly packed, few other species grow in the humus.

| Silver fir |

The silver fir is often found among beech trees where it can be spotted by its tall, dark silhouette. It is also found growing in 100% fir forests, especially in shady spots near the top of the mountain level (around 1,800 m). Another tree that will grow in different types of soil, silver firs form a shady, silent cover for undergrowth.

At the same height as the silver fir but preferring south-facing slopes sheltered from wind, rain and lasting snow, you will find Scots pine. Its blue-green foliage and the scaly bark which glows red near the top filter the light, providing good lighting conditions for flora similar to neighbouring heath and grassland. The hooked pine takes over on higher slopes, where conditions are harsher. It is found from the uppermost parts of the mountain level and particularly at subalpine level between 1,800 and 2,300 m. As hooked pine woods are not normally very dense, there is plenty of room for other plants to grow.

| hooked pine |

| Rubigenous rhododendron|

Of these: The rubigenous rhododendron prospers on the acidic sol of stony, shaded slopes. The snow covering its branches stays until around June, protecting the delicate buds from late frost. Growing closely together, the shrubs can cover wide areas and create pink-flowering heaths. The Pyrenean willow prefers chalky soils and is limited to areas where winter snow remains until the spring. It forms fairly sparsely populated grey-green heaths, home to a wide variety of chalky soil-loving flora growing at high altitudes (especially mountain avens). The bearberry: usually found on sunny slopes, the bearberry grows as well on predominately limestone rock as on siliceous escarpments. It withstands early thaws, huge temperature variations between day and night, and prolonged drought in the summer.

Pyrenean broom with its upright stems forms densely-packed bushy or heath-type cover only in siliceous soil on sunny slopes in the eastern Pyrenees. Its bright yellow flowers colour whole mountainsides in late spring and early summer. At the alpine level, above 2,300-2,400 m, woody plants become scarcer even though some hooked pines are found up to about 2,600 m.

| Pyrenean broom |

| snowbed willow |

Some trees and shrubs grow in hollows where snow stays until July. Stems trail on the stony ground, forming microforests just a few centimetres tall: The snowbed willow on siliceous soil (such as granite, gneiss, shale or sandstone) The net-vein willow and salix retusa on chalky soil.

Sometimes, altitude is not the main factor determining plant cover. Some species only grow on or near the same environmental elements such as rock faces, scree or mountain streams. on limestone rock faces: Pyrenean honeysuckle: clusters of white flowers brighten towering cliff faces from May on, the small bushes being solidly rooted in cracks in the rock. in scree: Alpine buckthorn. The bush's springy stems bend over onto the ground at the first snowfall. They thus escape the destructive force of successive avalanches during the avalanche season. near springs and along the banks of high mountain streams: the tea-leaved willow whose modest or upright tufts mark the tumbling path of the crystal-clear water.