Walnut (Juglans regia)
It is a deciduous tree (up to 25 m high). The trunk has a whitish colour and the branches are alternated, with a tough reddish-brown bark. Buds are blackish-brown and scaly. The young leaves are aromatic and a bit sticky. They are set alternately and exhibit a glabrous and flat petiole. They are composed, with between 7 and 9 leaflets (composite leaves), elongated and with a sharp apex and a full edge. They have a central marked nerve from which 20 side-nerves develop. The walnut flowers are unisexual, that means, whether male or female. Male flowers are set on hanging groups (aments), located on the fallen leaves armpits from the previous year. Female flowers appear on sprout tips of the current year in groups of three. The walnut's fruit is known as a nut. There are 4 nuts grouped in a single peduncle, exhibiting a fleshy green cover which turns brown when ripe.
WHERE DOES IT LIVE?
It prefers fresh and shady areas, like valley bottoms with rich and deep soils, provided that they are not excessively acid nor flooded, to develop its powerful roots system. It can bear cold very well, but not late frosts, excessive drought nor severe prunings. Where there are walnuts, it is unusual to find other plant species growing, due to its shadow intensity and the allopathic effect of the species: the falling leaf remains contain tannins and other composites impeding other species to sprout and grow.
HOW DOES IT LIVE?
It multiplies thanks to its seeds and some varieties are grafted. Pollination is made by the wind (anemophil), helped by the fact that the pollen is light and kept by the feathery stigma, favouring its germination. As it has a few flowers compared to other species, it needs to get a great part of its flowers fertilized. Inflorescences must coincide, that means that, male flowers must spread the pollen when female flowers are receptive to enable pollination and fertilization. The walnut reproduction cycle is yearly, so it starts in spring with the flowering and ends the following autumn (April to May) with the seeds dispersion.
WHERE CAN WE SEE IT IN THE MALAGA PROVINCE?
In the Málaga province, it can be found all over the territory, and is always associated with fresh, shady and deep soils areas. It is always associated with humans, so it is easy to find it near farms or cottages. It is present in the Ronda Hoya del Tajo and between Alfarnate and Alfarnatejo, for example. In the Great Path, a great walnut mass can be observed on stage 26, as well as isolated specimens on stages 10, 24, 25 and 28.
The walnut has a great economical value. Its wood is, added to the cherry tree, the most appreciated among Iberian trees, as luxury artefacts can be made with it: plates, panels, car dashboards, shotgun and gun butts, etc... There are famous altarpieces and choirs of many cathedrals exclusively made with walnut wood. In addition, its fruits (nuts) have a great value, as they are very nutritious and have multiple healthy properties.
Which species can it be mistaken with?
It is an unmistakable species because of the characteristics of its fruits. When there is no fruit, its composed leaves and its localisation also prevent confusions.