The Gibraltar Magazine

Our Trees

A number of different trees form part of the natural vegetation of Gibraltar. Most of them will be found on the Upper Rock, but a number can also be found in areas such as the Alameda Botanic Gardens, the gardens of The Mount and The Convent, Trafalgar Cemetery, etc. Inside these garden areas these trees can reach quite large sizes, whereas out in the wild they are usually smaller, and sometimes look more like large shrubs rather than trees.

In the Upper Rock, the principal tree is the wild olive, but it is believed that in the past other trees formed an important part of the vegetation. Such is the case of the carob, Ceratonia siliqua, and the nettle tree, Celtis australis. Today only a few of these species can be found in the Nature Reserve, but numbers seem to be on the increase.

The carob can reach sizes of up to 10m tall. Its gnarled trunk and branches are quite distinctive as are the catkin-like flowers which arise straight from the trunk and branches. The seed pods are from 10 to 25 cm long and around 2 cm wide. When ripe these are edible, and contain seeds that were once used as a unit of weight: the carat!

The nettle tree gets its name from the shape of the leaves which resemble that of the stinging nettle. However these leaves do not sting. The trees can reach heights of up to 25 m, and some outstanding specimens can be found in the Mount gardens. Many seedlings and small trees can be found in various places on the Upper Rock, in particular around Jew’s Gate. The fruit is edible when ripe.

Introduced throughout the Mediterranean from the Middle East, the fig, Ficus carica, is a familiar sight.

These deciduous trees range from 2 to 6 m tall, and can be found naturalised in many places, especially growing from old walls where they can cause extensive damage as their roots spread out. Care must be taken when handling the tree as the sap is a skin irritant and contact with it may result in blisters.

Two species of pine can be found on the Rock, both of which were probably introduced in the 18th century to provide shade along roadsides of the Upper Rock. The most common is the Aleppo pine, Pinus halepensis. This tree can grow up to 20 m tall. Its trunk and branches are often twisted, and the bark is dark grey with brownish fissures.

The cones are elongated, up to 12 cm long, and remain for some time on the trees after releasing their seeds. The stone or umbrella pine, Pinus pinea, is a taller tree, up to 30 m, with a straight trunk and umbrella-shaped canopy. The bark forms reddish scales. The cones are rounded in shape, up to 15 cm long, and fall unopened from the trees. The seeds are the edible piñones. Not strictly a tree, the ivy, Hedera helix, is an evergreen woody climber.

Its stems can reach up to 30 m, and the plant can form extensive cover over walls and cliffs. The leaves on non-flowering stems have 3 to 5 lobes, whilst those on the flowering stems are rounded to oval in shape. The best stands of this species on the Rock are in the south district, in particular inside North Gorge and surrounding cliffs. The black fruit is an important food source for birds.

Of the same family as the wild olive is the phillyrea, Phillyrea latifolia. This is a much rarer tree, which is only found in a limited area west of the Cable Car top station. These trees can reach up to 5 m in height, and can be distinguished by the dark green, lanceolate leaves which have finely toothed edges.

Leaf-miner insects seem to have a preference for the leaves of this species: the majority of the leaves will have the distinctive brownish tracks of these creatures as they feed inside the leaves.

There aren’t many trees to be found on the East Side of the Rock. Not many species will be able to survive the salty spray that covers the vegetation, especially during strong Levanter storms.

The small-flowered tamarisk, Tamarix parviflora, is one that can, and so will be found along the Red Gum White Iris White Snakeroot East Side, Europa Flats and Windmill Hill Flats. It is a native of the eastern Mediterranean region, but is planted and has become naturalised throughout. The small tree, or shrub, can reach up to 5 m. The leaves are tiny and scale-like. The pale pink flowers have four petals, and are around 4mm across. They are borne on elongated clusters up to 3 cm long.