The hazelnut, often called the filbert, is the edible nut produced by trees and shrubs belonging to the genus Corylus. This genus is part of the birch family, Betulaceae, and comprises roughly 15 distinct species distributed across the temperate zone of the Northern Hemisphere. Archaeological evidence indicates hazelnuts were a significant food source for human populations dating back approximately 10,000 years. The development of this cultivated food source is linked to its diverse geographic origins, which span three continents.
Native Range of the Common Hazel (Corylus avellana)
The Common Hazel (Corylus avellana) is the species responsible for the vast majority of the world’s commercial supply. This species is native to an expansive region stretching across Europe and into Western Asia. Its natural distribution extends from the British Isles and Scandinavia, south through the Iberian Peninsula and the Mediterranean basin, and eastward.
The range continues through the Balkans, the Caucasus Mountains, and into northwestern Iran. Western Asia and the Mediterranean region hold historical significance within this vast native area. Turkey, specifically the coastal regions along the Black Sea, lies within the heart of this native range and remains a center of genetic diversity.
Italy, also within the native range, became a key area for early cultivation. The nut’s specific epithet, avellana, possibly derives from the ancient Italian town of Avella. This species provides the genetic foundation for nearly all modern commercial varieties, such as ‘Tonda di Giffoni’ and ‘Barcelona’. The success of these cultivars is rooted in the species’ adaptability.
Diverse Native Habitats of the Corylus Genus
While Corylus avellana dominates commercial production, the Corylus genus is scattered across several geographically separated regions. North America hosts its own distinct native species, notably the American hazelnut (Corylus americana) and the beaked hazelnut (Corylus cornuta). These species occupy different ecological niches than their European counterpart.
The American hazelnut is native to the eastern half of the continent, found from Manitoba south to Georgia, often growing in woodlands and thickets. The beaked hazelnut has a wider distribution, stretching across much of Canada and the northern United States. These North American species produce smaller nuts than C. avellana and are important for wildlife and localized consumption.
The Asian continent also contributes to the genus’s diversity with species such as the Japanese hazel (Corylus sieboldiana) and the Siberian hazelnut (Corylus heterophylla). These species are native to temperate forests across China, Japan, Korea, and Siberia. This global distribution confirms that the hazelnut represents a family of species adapted to temperate climates worldwide.
Historical Domestication and Cultivation
Human interaction with the hazelnut began long before formal agriculture, with hunter-gatherer communities relying on wild nuts. Archaeological finds, including Mesolithic sites across Europe, contain evidence of mass collection and consumption. This long history positioned the hazelnut as one of the earliest fruit plants subjected to human management.
The shift toward organized cultivation first gained momentum in the Mediterranean region. Ancient Greek and Roman civilizations valued the nut for its nutritional content and cultural symbolism. Roman authors like Pliny and Virgil documented the hazel tree, and the Romans facilitated the spread of the plant across their empire.
Early cultivation involved selecting trees with desirable traits, such as larger, thinner-shelled nuts, moving the plant beyond its strict native range. The Roman practice of planting hazel groves, or nuceta, contributed significantly to establishing the hazelnut as a staple crop throughout Southern Europe. This process laid the groundwork for modern orchard practices.
Major Current Global Producers
Today, the geography of commercial hazelnut production reflects both the native range and historical cultivation efforts. Turkey is the dominant global producer, accounting for approximately 70-75% of the world’s supply. The majority of this production is concentrated along the Black Sea coast, in provinces like Giresun and Ordu, which directly overlap with the species’ primary native habitat.
Italy remains the second-largest producer, maintaining a strong tradition of cultivation in regions such as Campania, Lazio, and Piedmont. Italian production relies heavily on historical cultivars like ‘Tonda Gentile delle Langhe,’ demonstrating a continuous link to the Roman cultivation era. The third-largest producer is the United States, with almost all domestic production centered in Oregon’s Willamette Valley.
The Willamette Valley’s success resulted from introduction into a region with a mild, temperate climate that closely mimics the European native range. Other significant production centers include Azerbaijan, located in the Caucasus region near the intersection of the native European and Asian ranges. This global map of production is an outcome of the plant’s natural origins and centuries of human agricultural management.