- Turkish Filbert
- Turkish Hazelnut
The Turkish hazelnut, scientific name Corylus colurna, is a tree found primarily in Turkey, just like its name indicates. Turkish hazelnut also grows in some neighbouring countries in the Balkans and southwest Asia, such as Bulgaria and Iran.
This deciduous species is the largest variety of hazelnut and can grow up to 25 m in height, with a trunk diameter of maximum 1.5 m, covered in thick pale grey bark. The crown has a conical shape when the tree is young and expands with maturity.
The Turkish hazelnut leaves fall off in the cold season and have a length between 6 and 15 cm, with a width of 5 to 13 cm. They have coarse serrated and lobed edges and are covered by soft hairs on both sides. Side branches emerge at a perpendicular angle from the main trunk and tend to be short. As a result, they are very strong and give the tree a conical shape. The attractive symmetrical crown makes the tree very useful as a decorative species, especially in urban environments.
The Turkish hazelnut bloom begins at the start of spring, before the first leaves develop. The flowers are separated by sex and look very different. While the yellow male flowers can reach a length of 5 to 10 cm, the female ones are so small that only their red styles are visible and these are not longer than 1 to 3 mm. As a result, male trees are easy to identify because their flowers are actually visible.
Turkish hazelnuts look like most other nut varieties and have a length between 1 and 2 cm. They are encased in a husk with soft spines, about 3 cm in diameter. The tip of the nut is not covered by this husk. Turkish hazelnuts are found in groups between 3 and 8 fruits, clustered together. The Turkish hazelnut fruits become ripe in September and have the same taste as other varieties of hazel. Despite being edible, they have very little commercial value. This is due to the low size of the nuts and their very hard shell, which has a thickness of 3 mm that is very big relative to the overall size of the fruit. The species is more useful as rootstock for other hazel cultivars and it is widely found in orchards for this purpose, since it doesn’t develop suckers. It doesn’t produce fruits every year and it has an irregular cycle of two to three years. Only female trees have fruits.
Turkish hazelnut leaves are rich in flavonoids that have been isolated and tested by scientists. They were found to be very strong antioxidant agents, with a reduced toxicity. This makes them excellent natural alternatives to synthetic antioxidants, which are effective in repairing the damage caused by free radicals but have a toxic effect themselves.
The Turkish hazelnut fruits have very high energy contents and a serving of 100 grams provides no less than 628 calories. In addition, they are rich in many other nutrients. Turkish hazelnuts are a major source of linoleic acid, an essential fatty acid that boosts the levels of HDL (good) cholesterol while reducing the one of LDL (bad) cholesterol. Oleic acid and other varieties of mono-unsaturated fatty acids are also found in the Turkish hazelnut fruits. Scientists suspect that monounsaturated fatty acids are the secret behind the effectiveness of the so-called Mediterranean diet, since they reduce the risk of coronary artery disease.
Including Turkish hazelnuts in your daily diet provides a great mix of vitamins, minerals, dietary fibers and other beneficial compounds. Consuming them can protect from cancer and other serious conditions.
Hazels of all types are known for the very high content of folate. A serving of 100 g of raw nuts provides 28% of the recommended daily amount of this vitamin, or 113 µg. This compound is part of the B-complex vitamin and plays many important roles in the body. It is critical for pregnant women since a lack of it can cause newborn to have neural tube defects. It also protects against megaloblastic anemia.
Another essential vitamin found in generous amounts in hazelnuts is vitamin E. A portion of 100 g actually provides the entire daily required amount of this vitamin. It is a very powerful antioxidant that is able to protect the skin and mucous membranes from the action of free radicals because it is soluble in fats.
Similar to almonds, Turkish hazelnuts contain no gluten at all. Since they are rich in other nutrients, this makes them a great ingredient in special foods for people who suffer from celiac disease, allergy to wheat or other types of sensitivity to gluten.
Consuming all types of nuts is good for heart health because they are very rich in unsaturated fats. Turkish hazelnuts provide a lot of oleic acid, which is able to increase the levels of good cholesterol and decrease the level of bad one. Another compound found in nuts that is good for the heart is magnesium. It is required to maintain a balanced level of calcium in the muscles, which prevent irregular heartbeat and contractions. With enough rest between contractions, the heart muscle is able to rest properly, so a good intake of magnesium can be highly beneficial.
Hazelnuts actually include a type of vitamin E named alpha-tocopherol, which is very effective against bladder cancer and can reduce the risk of this disease by 50%. In addition, hazelnuts are very rich in manganese, an essential mineral that also plays a major role against various tumours. This element is needed for the natural defence mechanism of cells, since it is part of an antioxidant enzyme synthetized in the mitochondria.
A very important mineral supplied in generous amounts by nuts is magnesium, which controls the flow of calcium through cell membranes. The presence of calcium triggers both the contraction of muscles during times of activity and it also allows them to relax when they are not used. Muscular problems such as cramps, tension or fatigue are avoided in this way. Magnesium also plays a direct role in muscle contraction, according to the results of a study from Italy.
Vitamin E is one of the natural antioxidants needed by our body. It neutralizes the effect of ultraviolet radiation in sunlight and prevents skin cancer and early aging. A single cup of Turkish hazelnuts supplies almost the entire daily requirement of this vitamin. This makes Turkish hazelnut oil a useful cosmetic agent, due to its astringent effect, ability to hydrate the skin and pleasant aroma. It serves as a base or carrier oil in pharmaceuticals, cosmetics, as well as massage therapy or aromatherapy. It can also serve as cooking oil.
Besides other roles, most of the magnesium in the body is used in the structure of the bone system and it is critical for its durability. It is actually so vital to their structure that any excess magnesium is deposited on the bone surface, so the body can use it immediately if needed. Turkish hazelnuts are even better for bone structure because they also provide manganese, which is another essential mineral with a role in the durability of the skeletal system. Manganese boosts bone density, so it is vital for women during menopause, when it reduces the effects of osteoporosis.
Vitamin B6, which is found in large quantities in hazelnuts, is needed for the production of a number of amino acids used by the nervous system. One of the compounds that require vitamin B6 is myelin, the coating of nerve fibers. This chemical is critical for the operation of the nervous system because it greatly boosts the speed and accuracy of electrical signals. Other important bioactive compounds that include vitamin B6 in their structure are melatonin, serotonin, epinephrine and other neurotransmitters.
Manganese is needed for some other body functions, besides bone structure. It acts as a catalyst in the synthesis of fatty acids and cholesterol, an activator for a number of enzymes and a promoter of carbohydrate and protein metabolism.
Like most fruits and nuts, hazelnuts provide a large dose of dietary fibers. These are great for digestion because they regulate the transit of both food and waste through the intestines. This prevents constipation, increases the intake of nutrients and maintains the digestive tract healthy by ensuring a correct ratio between chemicals and the micro organisms that live there.
Turkish hazelnuts are a great source for many of the B vitamins, especially B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 and B9 (folic acid or folate). The body needs B-complex vitamins in order to process nutrients like carbohydrates, proteins or fats and transform them into usable energy. They are also widely used in other roles, such as the nourishment for nervous system. A good supply of B vitamins prevents disorders such as depression, stress or anxiety. They are part of the production chain of serotonin and other neurotransmitters, so they have a positive effect on memory. Vitamin B2 is used in the production of red blood cells, while vitamin B9 is needed for the synthesis of hormones. Vitamin B3 is used by the nervous and digestive functions and keeps the skin healthy. B complex vitamins are also needed for the production and repair of DNA.
The Turkish hazelnut tree is also used for ornamental purposes, both in Europe and the USA. Turkish hazelnut tree is very resilient and tolerates the worst of the urban environments, which makes it very popular in city landscaping and gardens all around the world. Turkish hazelnut is an excellent shade tree, with its narrow crown producing very dense shade. Turkish hazelnut is one of the best street tree species because it is not affected by urban air pollution. The narrow crown and the overall symmetrical shape of the Turkish hazelnut make it very attractive as well. Since the crown doesn’t spread much, it is optimal for zones where there is limited space in the air. Among its many urban uses are as a sidewalk tree, specimen tree or street tree. Turkish hazelnut is well adapted to wide lawns, as well as parking lot islands, since it needs only a small overhead. Turkish hazelnut is also planted for its fruit, although the commercial value is limited. Since it tolerates harsh conditions, it is a good choice for dry or highly polluted environments.
Habitat and cultivation
The Turkish hazelnut enjoys positions with full sun exposure and humid soil with good drainage. However, it is able to tolerate a variety of adverse conditions after being established, including drought, cold or extreme heat. Turkish hazelnut can also grow on alkaline soils and it is not affected by any important pest or disease.
The species is difficult to transplant and the in the first summer after relocation it will need additional water. Turkish hazelnut requires as long as two years to become completely adapted to the new location and survive without help.
Seeds are the best and most common propagation option for the Turkish hazelnut tree. For best results, plant it in a cold frame in autumn, just after it matures. At the end of winter or the start of spring, the seed germinates if sown in this manner. Seeds from storage don’t germinate that easily and need 2 days of pre-soaking in warm water, followed by 2 weeks of warm and then as long as 4 months of cold stratification. It needs between 1 and 6 months to germinate at 20°C. The seedlings should be moved into individual pots as soon as they are large enough to handle. During the first winter, keep them in a protected location or a cold frame. In the next spring or summer the seedlings can be moved to their final location.
Turkish hazelnuts supply the entire group of B-complex vitamins. They are very rich in folate but also provide pantothenic acid, pyridoxine, riboflavin, niacin and thiamine. Another essential nutrient supplied in large amounts is vitamin E.
The Turkish hazelnut fruits also provide several minerals, in particular magnesium, manganese, potassium, calcium, copper, zinc, selenium and iron. Superoxide dismutase, a very strong antioxidant enzyme, needs copper and manganese as co-factors. Calcium, magnesium and phosphorous are the structural building blocks of bones, while a good supply of iron prevents anemia.