Hazel
Hazel (Corylus avellana) is a deciduous shrub or small tree in the birch family (Betulaceae). It is a natural part of Norwegian deciduous forests and is found mainly in temperate forest areas, but also grows in boreal regions, especially in the south. In Norway, it is most common in Eastern Norway and along the coast north to Steigen in Nordland12.
Introduction to Norwegian flora
Hazel is one of the oldest tree species in Norway and was introduced early in the postglacial warm period, approximately 11 years ago. The climate during this period became warmer after the last ice age, which allowed hazel and other heat-loving species to spread northwards. It quickly established itself in coastal areas and in lower-lying areas, and is still a characteristic feature of the broadleaf forest today.3.
Characteristics
Hazel usually grows as a shrub with several trunks from the root collar, but can also develop a main trunk and grow up to 12 meters tall under optimal conditions. The bark is smooth, brownish-gray with light pores, and on young shoots it can be reddish-brown and slightly hairy456The leaves are round or oval with a heart-shaped base and a double-toothed edge. They are hairy on both the upper and lower sides, and usually emerge in May.
The crown varies with growing conditions. In sunny areas it forms a dense, compact crown, while in shade it grows more open with elegant, horizontal branches. Young shoots can grow quickly, and older branches develop thicker bark and a coarser structure56.
Growth conditions
Hazel thrives best in calcareous, humus-rich and nutrient-rich soil. It is often found in forest edges, scrub and open deciduous forests. It tolerates partial shade, but prefers brighter conditions for optimal nut production. In Norway, it grows up to 600 m above sea level in southern Norway and is also found in inner valleys such as Vestre Slidre and Sør-Fron.6.
Ecological significance
Hazelnuts are of great ecological importance. They are a pioneer species and improve soil by providing organic matter through their leaves and nuts. Wildlife such as squirrels, mice and deer feed on hazelnuts, and birds such as nuthatches and woodpeckers use the plant as a food source and shelter.7In addition, the leaves are host to insects such as brown leafhoppers and aphids, which are part of the food chain.
Climate benefits
Like all trees, hazel contributes to carbon sequestration through photosynthesis. Hazel's rapid growth and biomass production make it effective for local CO₂ sequestration.5The foliage also acts as a filter for dust and particles, thus contributing to better air quality. It improves soil structure and water infiltration, and plays an important role in the soil's carbon cycle.
Cultural-historical significance and uses
Hazelnuts have been a valuable food source since the Stone Age. They are rich in fat, protein, vitamins (especially E and B-complex), minerals (such as magnesium and iron) and fiber. In Norway, the nuts were used as winter provisions, and it is still common to gather them in southern Norway today. Hazelnuts are used both raw and as an ingredient in pastries, chocolate and nut butters. They also have nutritional benefits for the cardiovascular system and can be included in a plant-based diet.
The wood of the hazel tree is tough and flexible, and was used for bows, fishing rods, tools and barrel bands.8. Hazel branches were woven into fences and baskets. In modern times, the wood is used for handicrafts and garden stakes. Hazel has also been used medicinally: the leaves and bark contain astringents that were used to stop bleeding and treat skin ailments. In folk belief, nuts were given as gifts during festivals and symbolized fertility and happiness.
