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Practical ecological knowledge for the temperate reader. |
Family: Betulaceae - Birch Family
"Corylus cornuta is a deciduous Shrub growing to 3 m (9ft 10in).
It is hardy to zone (UK) 4. It is in flower from Apr to May, and the seeds ripen from Sep to October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.The plant is self-fertile.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very alkaline soils.
It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure."[PFAF]
"Hazelnuts have a localized distribution on Vancouver Island. The nuts were a favourite food of the Island Salish where they were available. Paul (1968) remembers gathering them at Goldstream when he was young." [Turner&bell]
Synonyms
Var. californica
Origin Status:
Native [E-flora]
General:
Deciduous shrub, 1-3 m tall with many stems, densely clumped or spreading by suckers; twigs sparsely to moderately hairy, sometimes glandular.
[IFBC-E-flora]
Leaves:
Alternate, deciduous, elliptic to oval, leaf blades heart-shaped with a sharp-pointed tip, doubly saw-toothed, paler below than above, 4-10 cm long, turning yellow in the fall.
[IFBC-E-flora]
Flowers:
Male flowers in catkins appearing before the leaves in spring; female flowers in a very small catkin with protruding red stigmas.
[IFBC-E-flora]
Fruits:
Edible hard-shelled nuts completely enclosed by bristly bractlets, in 2's or 3's at the end of branches, barely 1.5 cm long, thinly hairy or glabrous.
[IFBC-E-flora]
Habitat / Range
Mesic sites in the lowland and montane zones; var. cornuta - common south of 57degreeN east of the Coast-Cascade Mountains, var. californica - frequent on S Vancouver Island and the lower Fraser Valley, becoming rare to the east; E to NF and S to GA (var. cornuta) and E to ID and S to CA (var. californica). [IFBC-E-flora]
Ranging from Nova Scotia to British Columbia, south especially in the mountains to Georgia, Tennessee, Kansas, and Oregon; and a variety of it is found in the mountains of California. [EWP]
Notes:
Two varieties occur in BC:
1. Involucral beaks about twice as long as the fruit; silicles thinly short-hairy; twigs sparsely hairy............... var. cornuta
1. Involucral beaks about equal in length to the fruit; silicles glabrous; twigs hairy, sometimes glandular............... var. californica (A. DC.) Sharp [IFBC-E-flora]
Nuts
"People of many tribes in California picked hazelnuts (Corylus cornuta var. californica) by the basketful and ate them raw or roasted. They were often hulled by hand at leisure in the village. The Wintu also hulled hazelnuts by beating them with a willow switch. Often a supply was dried, stored in the shell, and kept on hand through the winter and spring. The Yurok pounded hazelnut kernels into a flour, added warm water, and used the mixture to nurse sickly children or ill persons with weak stomachs." [Anderson TTW]
Seed Spicules: "The nut is invested with a scaly involucre, projecting beyond it like a beak, and thickly covered with short spicules like those of Mucuna pruriens DC. (Fam. Leguminosae.) These spic-ules have been employed by Huebener as an anthelmintic. They operate in the same way as cowhage, and may be administered in the same manner and dose.... An alcoholic extract is placed upon the market under the name of mensan which these authors have found useful in the treatment of uterine hemorrhages due to chronic endometritis. The dose employed was a tablespoonful twice a day." [Remington USD20]
Branches & Leaves: An infusion has been used in the treatment of heart complaints and intestinal disorders[257]. [PFAF]
Bark: A decoction has been given to children to alleviate teething pain[257]. [PFAF] "The tree bark has been traditionally used as a soothing tonic for sore throats and upset stomachs." [Jones TDFB] "Boiled bark used to induce emesis." [Meuninck EWPUH]
"An easily grown plant, it succeeds in most soils, but is in general more productive of seeds when grown on soils of moderate fertility[11, 200]. It does less well in rich heavy soils or poor ones[11, 63]. Does well in a loamy soil[11]. Very suitable for an alkaline soil[11], but it dislikes very acid soils[17]. Tolerates a pH in the range 5.8 to 7.5. Plants are fairly wind tolerant[1, 11]. Plants are hardy to about -30oc[160]. They thrive in a short growing season[160]. This species is occasionally cultivated for its edible seed in N. America[61] but is of no value in Britain as a seed bearer[11]. Plants can bear fruit in 5 - 6 years from seed[160]. Members of this genus bear transplanting well and can be easily moved even when relatively large[11]." [PFAF]
Controlled Burning
"In addition to being a food source, hazelnut shrubs provided Indians with materials for many cultural uses—but only after the shrubs had been burned, because fire induced the sprouting of straight young shoots. The young hazelnut shoots that came up after fires were used by a number of northwestern tribes to make various kinds of baskets, including cradleboards and carrying baskets. The new growth was also twisted to make rope, and employed in the construction of fish traps for salmon and surf fish baskets." [Anderson TTW]
"... the Karuk and Wiyot burned “hazel bushes” for “better basketry warp.” Yurok weaver Lucy Thompson reported that the Yurok deliberately set fires to enhance nut production.... the “hazel shoots were better when the brush was burned down each year.”" [Anderson TTW]
Propagation
"Seed - best sown as soon as it is harvested in autumn in a cold frame[164]. Germinates in late winter or spring. Stored seed should be pre-soaked in warm water for 48 hours and then given 2 weeks warm followed by 3 - 4 months cold stratification[164]. Germinates in 1 - 6 months at 20oc[164]. When large enough to handle, prick the seedlings out into individual pots and grow them on in a cold frame or sheltered place outdoors for their first winter. Plant them out into their permanent positions in late spring or early summer[K]. Layering in autumn. Easy, it takes about 6 months[78, 200]. Division of suckers in early spring. Very easy, they can be planted out straight into their permanent positions."[PFAF]
"Hazels are 10 species of deciduous shrubs or small trees that often occur in the understory of temperate forests in the Northern Hemisphere. They are widely cultivated for ornament or for their nuts, and also for poles produced by coppicing" [Allaby TF]
"Hazels and filberts are deciduous shrubby nut-bearing species of the genus Corylus and the family Betulaceae. Filberts are of the species C. maxima and hazelnuts (or cobnuts) of the species C. avellana; although many of the good fruiting cultivars are a result of hybrids between the two species and with other Corylus species. The names have become confused over the years and some hazels are called filberts and vice versa" [Crawford TGOP]
"Hazel trees are often biennial in their cropping nature, with a heavy crop year alternating with a light or no crop year. This goes for wild trees as well as the cultivated types you might deliberately have planted. Squirrel problems are always worse when wild trees are having a light year...." [Crawford FFFG]
"Hazelnuts have a spreading type of growth habit and can get to be as wide as they are tall. Leave 20–30 feet between trees." [Elzer-Peters NWFVG]
"You can grow hazelnuts throughout the Northwest, but trees are damaged when temperatures drop below 15oF" [Elzer-Peters NWFVG]
Nut Storage: "They will need drying to store (in-shell is best), after which they will store for several years at room temperature." [Crawford FFFG]
"Apart from the edible nuts, hazels are best known for their use as a coppice species. The poles from coppice (‘wands’) are long and flexible and have been traditionally used for many years for wattle fencing (branches are usually split, then weaved to make sections of fence); water diviner’s rods; thatching spars; walking sticks; fishing rods; basketry; clothes props; pea and bean sticks; hedging stakes used when laying a hedge; firewood, notably for brick kilns and baking ovens; construction of wattle and daub walls; crates; hurdles; barrel hoops; and fascines for laying under roads in boggy areas." [Crawford TGOP]
"Hazel wood is soft, elastic, reddish-white with dark lines, and is easy to split but not very durable. Older wood has been used by joiners and sieve makers, and charcoal from the wood for gunpowder manufacture. Root wood, veined and variegated, was once used for inlay cabinet work." [Crawford TGOP]
C. avellana, cornuta, rostrata, and americana; Tannins, essential oil, ferric oxide, betasitosterol; For coughs, colds, diuretic, prostaglandin inhibition, antiinflammation.[CRNAH]
kernel of Corylus heterophyila: "Regulating the middle-energizer, inducing appetite and digestion and improving acuity of vision." [Xinrong TCM]
"Corylus heterophylla and C. mandschurica: Two temperate, deciduous, broad-leaved shrubs of the same genus, with seeds containing 20% starch. They also contain tannin in leaves (6-14%) and in
bark (9.4%)." [McKell BUS]
"Hazels are an excellent hedging species, though fruiting will be much reduced in an exposed location. The foliage is also attractive to grazing animals if they can get to it." [Crawford TGOP]
Corylus sp. are a confirmed host of Tuber Spp. Corylus avellana has been found to host T. melanosporum and T. magnatum. [Cairney EF] Tuber excavatum EM with Corylus [FIE Cambridge] C. avellana is a main host plant for T. magnatum, T. aestivum group and T. albidum group. "Clonal material of suitable hazel cultivars may be used to ensure greater yield and uniformity of cropping (Mamoun & Olivier, 1996). The seedling roots of potential hosts are inoculated by dipping them in a suspension of ascospores, or seedlings can be naturally infected by growing them close to mature mycorrhizal trees where infection occurs by mycelial contact."[IntrotoFun3]
The Heterobasidiomycetes, Sebacina sp., are "EM with a range of temperate trees including Fagus sylvatica and Corylus" [FIE Cambridge]
Corylus sp. can host Cantharellus ECM fungal sp. [SoilBio-41]
Mycoheterotrophy: "Neottia is a genus of ca. 60 species with a distribution ranging through the temperate and subarctic Northern Hemisphere.... N. nidus-avis has been found to associate with Sebacina fungi that are ectomycorrhizal with surrounding trees, including Fagus sylvatica and Corylus sp." [Merckx Myco]
"Eastern filbert blight (Anisogramma anomala) is a serious disease
in North America. The American hazel, Corylus americana, is
the natural host of this disease but it is far more devastating to
the European species grown in North America. It is not present
in Europe. In infected trees, yields rapidly decline and large
cankers form that can girdle entire limbs. Plants are killed a
few years after the cankers spread to the main trunk. Most
cultivars are susceptible.... The best
control is to cut out and burn infected branches." [Crawford TGOP]
"Hazelnuts do have some pest problems. Aphids can eat the tree leaves but
respond to insecticidal soap. The ilbert worm can be controlled with an
application of B.t. in early July and again three weeks later." [Elzer-Peters NWFVG]
"Collecting Seeds: When the husks dry, squirrels often get them first, so we pick the clusters of nuts while the husks are still green" [NSSH Bubel]
"Breaking Dormancy: For spring sowing, prechill the nuts for several months" [NSSH Bubel]
Origin Status: Exotic [E-flora-2]
Habitat / Range "Moist meadows and thickets in the lowland zone; rare on Saltspring Island and in the Lower Fraser Valley; introduced from Europe." [E-flora-2]
Hazards "In Europe, hazelnuts (Corylus avellana) are a frequent cause of food allergies especially among susceptible consumers. Allergy to hazelnut can be severe and occur at young age." [EMNMPV.1]
Food Use
"Nutella, the supermarket staple beside the peanut butter, is a nearly addictive hazelnut spread. It’s the way many people are introduced to hazelnuts." [Lincoff TJF]
"Corylus avellana is indigenous to Europe and western Asia. Recently, using chloroplast microsatellites, hazelnut appeared to have been domesticated independently in three areas: the Mediterranean, Turkey, and Iran (Boccacci and Botta 2009)." [EMNMPV.1]
"The world’s leading producer of hazelnut is Turkey, specifically in the Ordu province. Hazelnuts are also grown extensively in Australia, New Zealand and Chile." [EMNMPV.1] "Turkey ranks the first producer country in the World. The shelled hazelnut production between 1997-2001 is about 600.000 tons, which amounts to nearly 80% production of the World (DIE, 2001; Union of Agricultural Cooperatives [Fiskobirlik], 2002)" [Logrieco OTFME]
"Raw kernels whole or pieces and diced are used as snack food, dessert, in muesli and in a wide range of food products. Blanched kernels with skins removed by heating are used as ingredient in many foods, for example gelati requires varieties that blanch well. Roasted kernels are used in confectionery and bakery products. Hazel nut is widely used in breads, cakes, biscuits, sweets, chocolates, ice-cream, etc. Hazel nut meal made from raw or roasted hazelnuts that have been finely chopped or ground is used as food ingredient in bakery products. Hazelnut meal is also used to make a paste or powder called praline, a flavouring product which is used in a wide range of products such as confectionery. One popular product is praline belge or Belgian chocolates. Hazel nut is also used in combination with chocolate for chocolate truffles and products such as Nutella. In Australia, hazelnut is used in the manufacture of Cadbury eponymous milk chocolate bar which is the third most popular brand in Australia. ... Hazelnut oil obtained from cold pressed raw kernels is a strongly flavoured, clear, yellow cooking oil used in salad dressing and baking; it is rich in vitamin E and monounsaturated fatty acids. Hazelnut butter is considered as a pleasant and nutritious spread. In the United States, hazelnut butter is being promoted as a more nutritious and healthier spread than peanut butter. Hazelnut can also be liquidized and used as a plant milk and is processed into vodka-based Hazelnut liqueurs.... Hazelnut is popular as a coffee flavouring, especially in the form of hazelnut latte. The flour obtained from residual meal after oil extraction is used as gluten free flour substitute." [EMNMPV.1]
"Hazelnut liqueurs like Frangelico and Fratello are sweet blends of hazelnut and other spices like vanilla and chocolate. The Frangelico distillery crushes its toasted hazelnuts and then extracts the flavors in a mixture of water and alcohol. Some of this infusion is distilled, so that the final version contains both the distillate and the infusion. Also added are vanilla, cocoa, and other extracts." [Stewart TDB]
"hazelnuts are an ingredient in small-batch bitters, and pure hazelnut extract can be used as a cocktail ingredient or whipped into cream for nutty coffee drinks." [Stewart TDB]
"If storage conditions are not suitable, it is well known that, in a short period, the nutrient value of hazelnuts decreases and unpleasant odors appear. This odor and flavor are still an important problem, especially in roasted hazelnuts, which lower the economic value of the product (Savage et al. 1997; Seyhan et al. 2002; Kirbaslar and Erkem 2003)." [Kristbergsson TF]
The kernal of C. avellana yeilds an estimated 1000kg/ha of oil [Lichtfouse SAR 11]
Other Uses
"Hazelnut can also be planted as a hedge plant. Hazel nut seed oil is also used in paints, cosmetics (as an ingredient of nourishing and moisturising body and hand creams, lotion, soaps, face mask, ointment), wood polish etc. The finely ground seeds are used as an ingredient of face masks in cosmetics. The bark and leaves are a source of tannin. The wood is used for inlay work, small items of furniture, hurdles, wattles, basketry, pea sticks, bows and arrows. The wood also provides a good quality charcoal, used by artists." [EMNMPV.1]
Smoke: "The leaves were smoked all over Eurasia for unspecified purposes (Lewis and Elvin-Lewis 2003)." [UAPDS]
"The bark, leaves, catkins and fruits have been used in traditional medicine. They have astringent, diaphoretic, febrifuge, nutritive and odontalgic properties. The seed is tonic and stomachic. Hazelnut oil has been reported to have a gentle but constant and effective action in cases of infection with threadworm or pinworm in babies and young children." [EMNMPV.1] "the ash from a burnt hazel stick was put on burns in Monaghan,56 the bark was applied to boils and cuts in Kerry57" [MPFT]
"With hazel’s supernatural background, one would expect the medicinal use to be hinged firmly on to magical practices. So they are, but there one or two that seem to be pragmatically genuine. Herbalists still maintain that hazel nuts improve the condition of the heart, and prevent hardening of the arteries (Conway), while they say in Wiltshire that they are good for curing coughs (Wiltshire)." [DPL Watts]
"On average, hazelnuts supply 628–677 kcal/100 g from: proteins (14–15 %), fats (60.8–66.3 %: SFA 4.9 %, MUFA 52.2 % and PUFA 6.2 %, mainly oleic and linoleic acids), starch (0.48–2.1 %), sugars (3.9–4.3 %, mainly sucrose, fructose and glucose) and dietary fibre (6.1–9.7 %). Besides the high levels of protein (that includes some essential amino acids) and unsaturated fats, hazelnuts are good sources of oil-soluble vitamins such as a-tocopherol (15–25 mg/100 g), ß-tocopherol (0.33 mg/ 100 g) and phylloquinone (14.2 µg/100 g) (INSA 2015; USDA 2015). Hazelnuts also contain the water-soluble B vitamins thiamine (0.30–0.64 mg/100 g), niacin (1.8 mg/ 100 g), riboflavin (0.11–0.16 mg/100 g), folates (73–113 µg/100 g) and vitamin B6 (0.56–0.59 mg/100 g) (INSA 2015; USDA 2015) and supply relevant amounts of the micronutrients Mn (6.18 mg/100 g) and Se (2.4 µg/100 g)." [Delgado CMD]
"In another study, the main constituent of hazelnut was found to be fats ranging from 56% to 61%, being the nutritional value around 650 kcal per 100 g of fruits (Oliveira et al. 2008)." [EMNMPV.1] "Hazelnuts are rich in protein, amino acids (17), complex carbohydrates, dietary fibre, vitamin E, zinc, iron, calcium, potassium, manganese, magnesium, selenium, copper and monounsaturated and polyunsaturated fat. Moreover, they contain significant amounts of thiamine, vitamin Es and vitamin B6, as well as smaller amounts of other B vitamins. The fats are mainly monounsaturated oleic acid. Additionally, one cup (237 ml) of hazelnut flour has 20 g of carbohydrates, 12 g of which are fibre. Hazelnut also contains phytosterol (E-cytosterol), stigmasterol, campesterol, E-sitosterol, vitamin K, choline, betaine, E-carotene, D-carotene, lutein + zeaxanthin and antioxidants." [EMNMPV.1]
"The average microelement concentrations in hazelnut varieties were found to vary in the following ranges: B 13.63–23.87 mg/kg; Co 0.47– 0.82 mg/kg; Cr 0.22–0.52 mg/kg; Cu 16.23–32.23 mg/kg; Fe 31.60–51.60 mg/kg; Li, 0.035–0.042 mg/kg; Ni 0.58–2.58 mg/kg; Se 0.96–1.39 mg/kg; and Zn 22.03–44.03 mg/kg (Simsek and Aykut 2007)." [EMNMPV.1]
"Hazelnut was found to possess one of the highest PAC (proanthocyanidin) content among superfood.... Studies showed that the antioxidant capabilities of PACs were 20 times more potent than vitamin C and 50 times more powerful than vitamin E." [EMNMPV.1]
"Flavonols were only found in whole hazelnut kernels. Individual phenolics content , with the exception of gallic acid, was found to be highest in whole unroasted hazelnuts and was significantly lowered after skin removal. Similarly, total phenolic content and antioxidative potential was reduced when skin was removed. Roasting had a significant negative effect on individual phenolics but did not impact on the total phenolic content and antioxidative potential of kernels. The scientists asserted that from a health promoting phytochemical composition of hazelnuts, the consumption of whole unroasted kernels with skins should be preferential to peeled kernels either roasted or unroasted." [EMNMPV.1]
"Hazelnut oil is rich in oleic acid and also contains linoleic acid.... The level of saturated acids is low. Hazelnuts grown mainly in Turkey and also in New Zealand produce 55 to 63% of oil. The fatty acid composition is very similar to that of olive oil, and hazelnut oil is sometimes added as an adulterant to the more costly olive oil. There have been several reports on methods of detecting this adulteration, many of them related to the presence of filbertone" [CRC TLHB]
Anticancer "Both shell and leaf extracts of Corylus avellana contained taxanes (Ottaggio et al. 2008). Of these, paclitaxel, 10-deacetylbaccatin III, baccatin III, paclitaxel C, and 7-epipaclitaxel were identified and quantified. The content of total taxanes in leaves was higher than in shell....Paclitaxel is an effective antineoplastic agent originally extracted in low yield from the bark of Taxus brevifolia." [EMNMPV.1]
Mycorrhizal Associations
"Many trees will host the Périgord black truffle, but hazel (Corylus avellana) is most commonly used because it can be grown relatively easily, it forms many fine roots that are readily converted to mycorrhizas by the fungus (Chevalier 1998), and it commonly produces truffles several years earlier than other host plants (Giovanetti et al. 1994, Hall et al. 1994). Other host plants include Mediterranean hazel (C. colurna and C. heterophylla)" [EPMW Hall]
"For the cultivation of Perigord black truffle (T. melanosporum), Quercus pubescens and Q. ilex are considered better candidates than hazels (Corylus spp.) in European counties. However, hazels performed better in EMM production than oaks in Australia and New Zealand. Furthermore, among the species of hazels, Corylus colurna was better than C. avellana." [SoilBio-41]
"the hazelnut tree (Corylus avellana), which has an abundant root system, is an excellent carrier of mycorrhiza as well as a colonizer of the soil by the truffle, but it is agriculturally more demanding than the oak" [Chang BCEM]
"Like Oregon truffles, T. lyonii is frequently collected in natural forests but is also observed ... as a contaminant in orchards of Corylus avellana L. inoculated with European truffle species (Bruhn 2007; Tom Michaels, personal communication)." [SoilBio-34]
Journals of Interest