Hazelnuts are a species of tree in the Corylus family and are often referred to as filberts. There are several native species in North America but the European hazelnut (Corylus avellana L.) is the primary species grown for commercial purpose.
Most of the production in North America is based in Oregon, while Turkey is the major producer worldwide. In B.C., commercial production of European and hybrid cultivars is centred in the eastern Fraser Valley, mainly around Chilliwack and Agassiz, though there are orchards scattered in the southern Interior and on Vancouver Island.
Hazelnuts are a deciduous large shrub or small tree and their height characteristics are dependent on the species and variety. The European and hybrid varieties that are normally grown in orchard settings are trained as a small tree usually averaging 4.5 -7 m in height. The hazelnut itself is a small brown oval nut that varies in size depending on the particular variety. Hazelnuts grow in clusters of one to six nuts, each covered by a shell and a husk that encases the nut.
When the nut is ripe, the husk of some species and varieties releases the nut while in others the husk must be picked and mechanically separated from the nuts. The kernel of the nut is edible and used raw or roasted and as an ingredient in many commercial, baked and culinary products.
The publication “Growing Hazelnuts in the Pacific Northwest: Pollination and Nut Development” published by the Oregon State University Extension Service provides an excellent botanical overview and explains why a hazelnut orchard must be carefully designed. It discusses which varieties to choose to maximize production.
Hazelnut harvesting is normally done in October on the coast. Fresh nuts are washed, dried and size graded in preparation for marketing. For nuts to keep well, they should be dried to about 10% moisture content and stored in a cool dry location.