Medicinal Trees: Oak
Also, Known As:
- Gospel Tree
- Tanner’s Bark
The oak is a mighty and majestic tree that has the aptitude to grow up to a height of 90 feet (30 m), have a circumference of about 33 feet (10 m) and survive for as many as 1000 years! The oak is indigenous to North America where over 80 species of the tree are found. All species of the oak are beautiful deciduous trees having grayish, furrowed barks and shed their leaves during the fall. The roots of the tree are spread over a wide area and a mature oak tree may often dominate lesser locations. The timber of the oak is light brown in color, solid and weighty having a compact grain and are ideal for making furniture and flooring. The leaves of this imposing tree are bifurcated into quite a few curved sections. The fruit of the oak is an even acorn (an ovoid nut) that turns caramel hue when ripe and having a carved cap that wraps almost one-fourth of the fruit. Usually, a healthy oak tree that is about 25 years old is capable of bearing as many as 25,000 acorns annually.
The oak blossoms during the period between April and May and its seeds mature in October. The flowers of the oak are monoecious (each flower has only one sex – male or female) by nature and are usually pollinated by the wind. However, most oak trees are found to bear different flowers having either of the sexes. The oak tree has a preference for loamy or medium and clay (heavy) soils, but they are able to grow in heavy clay soil too. The plant also has a preference for basic (alkaline), acid and neutral soils. The plants need an arid or moist soil and are able to grow in sunlight as well as semi-shade conditions as in the slightly forested areas. Although the oak plant is able to endure strong winds, they do not survive well when exposed to maritime conditions.
The botanical name of the oak – Quercus, is derived from the Celtic terms ‘quer’ denoting ‘good’ and ‘cuez’ meaning tree. In addition, the tree has a common name – chen, meaning beautiful. Long back, the Celts believed the oak to be a sacred symbol. In fact, the Druids harvested mistletoe on the sixth lunar day of December with a gold sickle and heralded the arrival of the New Year chanting ‘To mistletoe, the New Year’. On the other hand, farmers used the acorns to make flour for several years. Even to this day, a number of members of the Berber tribes use the acorns to produce a nourishing breakfast cereal known as ‘racahout’. References of the oak are found in the Greek and Roman mythologies too. While the Greeks related the oak to the ruler of the Greek gods Zeus owing to the might and muscle of the tree, the Romans associated the majestic tree with Jupiter, the Roman god considered to be equivalent to Zeus. In fact, the custom of reveling in ceremonies under the shade of the mighty oak trees persisted even after Christianity was introduced. Therefore, it is not surprising that the oak tree has obtained it English designate ‘the gospel tree’ or ‘the prayer tree’.
The Goths or people inhabiting ancient Germany regarded the oak tree as a mark of might and victory. Hence, the term ‘as strong as an oak’ came into existence and is profoundly establish in people’s memory even to this day. During the Middle Ages as well as the Renaissance, unidentified healers utilized the leaves as well as the bark of the oak internally to treat hemorrhaging, diarrhea, tuberculosis and even rickets. They were used externally as a poultice to heal wounds discharging pus. The powder of the leaves and bark were applied externally to stop bleeding nose, while talc prepared with them were used externally to end the hemorrhaging or uncontrolled loss of blood.
In addition, the bark of the oak tree was frequently blended with iron salt to color textiles black. However, to some extent, people across the globe used this combination to tan hides. The timber obtained from the oak tree is economically very viable and used as a raw material for making furniture, flooring, constructing house frames as well as railroad framework. However, in the ancient time, the most important use of the oak tree was perhaps building ships. In fact, the oak was a natural resource that was extremely desired by the new settlers, especially in North America. Within a span of around two centuries, the English, as well as the French, totally pillaged hundreds and thousands of acres of white oak trees from southern Quebec in Canada.
Plant Parts Used:
Several parts of the oak tree are utilized for different purposes. While the buds and tender leaves of the oak are collected during the early phase of spring, the fruits or the acorns are harvested in fall and the outer bark, as well as the sapwood or inner bark, are utilized during the end of winter.
The Native North American tribes frequently used the white oak for remedial purposes. In fact, these indigenous people of North America held the oak tree in high esteem particularly for its antiseptic and astringent virtues. They used different parts of the oak tree to treat various medical conditions. Unfortunately, the oak is of little or no value at all in the present day herbal treatments. The inner bark or sapwood of oak encloses 6 to 11 per cent tannin, possesses potent antiseptic and astringent features and is additionally utilized as an expectorant (a medication that promotes the discharge of phlegm or other fluids from the respiratory tract) and a tonic (a medication that revitalizes or strengthens). To heal diarrhea and bleeding piles, sporadic fevers, asthma, consumption, coughs and colds, lost voice and other conditions, boil the oak bark in water and drink the infusion at regular intervals for a number of days. Many people often chew the oak bark to heal their mouth sores. The bark is also effective for external application to treat conditions like skin infections, rashes, bruises, burns, ulcers and other problems. It is also used as a vaginal douche (wash). It is best to collect the outer bark as well as the sapwood (inner bark) of oak trees during spring. All types of galls or blisters produced on the oak tree are potently astringent and may possibly be made use of in treating chronic diarrhea, hemorrhages, dysentery and several other conditions.
The timber of the white oaks is perhaps their most valuable possession as it is among the best available anywhere. However, often timber merchants mixed inferior quality oak wood along with white oak wood and market them for more profits. Compared to the timber of other varieties of oak, the wood of the white oak is more resistant to rotting. The cellular structures of the white oak are known as tyloses that provide the timber with a compact cellular structure even disallowing water to penetrate the wood. Tyloses actually grow inside the cells of living timber parenchyma (the fundamental tissue of plants, composed of thin-walled cells able to divide) into the cavities of cells controlling xylem. Timber of white oaks containing tyloses is utilized for making wine and whiskey barrels and outdoor furniture. White oak timber is especially used to make barrels to store whiskey and wines as they do not allow any leakage of the liquors. On the other hand, red oaks do not possess tyloses and, hence, it is not as impregnable as the white oak timber. In fact, the wood of the red oaks is mostly used as construction material, interior finishing of houses, cooperage (making or repairing barrels), shipbuilding and making agricultural instruments.
The Japanese use the timber of the white oak comprehensively or the manufacture of specific weapons for martial arts, such as ‘bokken’ and ‘jo’. The white oak is considered to be a valuable timber owing to the compactness of its grain, strength, resistance to water, honey fungus, rotting etc., and being comparatively splinter proof when it is broken due to any crash or force. Compared to the white oak wood, the red oak wood is significantly inexpensive. According to urban fable, the Japanese White Oak, known as ‘Kashi’ is the preferred wood, but the prevailing law in Japan prohibits harvesting any white oak trees. Hence, most of the white oak wood used to make weapons for martial arts in Japan is actually imported from the North Western United States.
Compared to the fruits of red oak, even the acorns of the white oak are a lot less bitter to taste. Although the acorns of white oak are comparatively smaller than the fruits of other varieties of oaks, but serve as a very beneficial food for the wildlife, especially for woodpeckers, turkeys, rabbits, deer, wood ducks, pheasants, grackles, jays, nuthatches, deer and thrushes. A number of indigenous tribes of North America also used the white oak acorns as a food. In fact, the white oak is the only identified food plant of the caterpillars belonging to the Bucculatrix ochrisuffusa and Bucculatrix luteella species.
The seeds of the white oak have a slightly sweet flavor and may be consumed fresh or after cooking. Usually, the seeds of the white oak are one-three cm in length and they mature in the first year. Chemical analysis of the seeds has demonstrated that they enclose approximately 66 per cent of carbohydrates and a mere six per cent of protein. They contain very poor amounts of tannin and require a bit of filtration or leaching. It is believed that the white oak seeds that have a reddish or pink spots on their shells comparatively have a sweeter flavor. The presence of any tannin that has a bitter taste in the white oak seeds may be filtered by meticulously washing the dried and pulverized seeds in water. However, during the leaching process, the seeds lose a number of their nourishing properties. The process of leaching the entire seeds may take a number of days or sometimes even weeks if done properly. An alternative process to leach the seeds is to cover them in a cloth bag and put them in a stream. Compared to leaching the whole seeds, it is much easier and faster to leach the powdered seeds. One is able to distinguish whether the tannin content in the oak seed has been removed by simply tasting the seeds or the powdered seeds. Traditionally, people leached the oak seeds by burying them in a marshy ground all through the winter. Later, during the spring, the seeds that had just begun to germinate were dug out and by this time they would have lost their astringent or bitter flavor. Many people consume the oak seeds after roasting them. Roasted oak seeds taste something in between popcorn and sunflower seeds. Interestingly enough, the roasted oak seeds may be used as a substitute for coffee, without the caffeine content of coffee.
Applying mulch or covering of leaves at the base of an oak plant helps to keep away slugs, caterpillars and other of the like. However, it is not advisable to use fresh leaves to cover the base of the plants because they have an aptitude to slow down the development of the plant. The bark of the oak tree contains rich amounts of tannins. The galls on the bark of the oak trees are basically outgrowths that are occasionally generated in large numbers. They are said to be caused by the actions of larvae of various insects found on the tree. In fact, the insects inhabit these galls and collect their required nourishment’s from within these outgrowths. After these insects develop from the larvae stage to the pupa stage and leave the trees, these galls or outgrowths on the bark of the oak trees may be utilized as valuable source of tannin that is used for dying fabrics black. The brown dye extracted from the bark of the oak trees or from the galls does not require any mordant or caustic. However, using a mordant or caustic may also help in obtaining dyes of different colors, including gold, yellow and chrome.
The timber of the oak trees is perhaps the most prized produce of this species of plant. The oak tree wood is tough, has a considerable weight, solid and strong. In addition, the grains of the wood are condensed making the timber durable. The weight of one cubic feet of oak timber is approximately 46 pounds. The oak wood is among the most significant timbers available in North America and is extensively used for a variety of purposes, including making cabinets, furniture, construction framework and agricultural instruments. One of the main uses of the oak wood in the earlier times was shipbuilding. The oak wood is also very useful for making the planks for barrels used for storing whiskey and wines. In addition, the oak wood also serves as a high-quality fuel.
Other Medical Uses:
- Excessive sweating
- Foot odor
- Frostbite and chilblains
- Pelvic inflammatory disease
- Pregnancy problems
- Stomach ulcers
Habitat of Oak:
As they are large and majestic trees, the oak grows well in grasslands or lands cleared of vegetation close to mixed deciduous wooded areas. As discussed earlier, the plants have a preference for high-quality, profound luxuriant loam that may be on the stiff side. The oak plants are capable of enduring acidic soil. When the oak plants are young, they are able to endure some extent of shade or semi-shade. The young plants also have an aptitude to tolerating reasonable exposure and survive well, but their development is slightly undersized. It may be noted that the white oak trees have a preference for summers that are warmer. A number of named varieties of oak trees are grown for their edible seeds. Normally, it takes around 30 years for the oak trees to produce good crops of seeds. Once the trees are 30 years old or above they produce plenty of crops once in every three years and moderate crops in the years in between. The oak trees can be harvested for their seeds for as many as 120 years, i.e. till they grow up to around 150 years. The oak trees blossom when the new growth appears in spring and the seeds mature in the first year itself, in October. The oak trees generally do not accept any kind of disturbance to their roots and, hence, they need to be planted in their permanent positions when they are young. However, the plants may need shelter from frosts during their first two winters. The oak trees have the ability to hybridize with other species in the genus quite easily. In addition, plants belonging to this genus are remarkably defiant against honey fungus.
The seeds of the oak are very sensitive and become unsustainable if they are permitted to dehydrate. Hence, they need to be preserved in a moist and cool condition during the winter, but it is advisable to sow them in seed beds outdoors immediately after they mature. However, it is essential to ensure that the sowed seeds are not consumed by squirrels, mice and other animals. They require adequate protection from such menace. In addition to sowing the oak seeds in outdoor seed beds, a small number of them can also be sown in pots having considerable depths in a cold frame. Even if the seeds are sown in deep pots, it ought to be remembered that oak trees have deep taproots and, hence, it is essential to plant them in their permanent positions outdoors at the earliest. In effect, the seeds that are sown outdoors in their permanent positions without any disturbance to their roots will develop into most excellent trees. It is important not to leave the oak plants in a nursery bed for over two growing seasons without transplantation. In case this happens, the transplantation or relocation of the plants will be severely affected.
- Bark: gallic acid, tannins, minerals (calcium, iron, potassium).
- Leaves: vitamins A, C and E, chlorophyll, mucilage’s, carbohydrates.
- Fruit: starches, sugars, tannins, calcium oxalate.
Possible Side Effects and Precautions:
Consumption of oak bark in excess may result in acute constipation. It is advisable to not cook any food with oak bark in cast-iron pans or pots since this results in the tannins present in the oak bark turning into toxins for the kidneys. It needs to be noted that when the oak bark is exposed to iron, it becomes toxic.
The buds of the oak are utilized to prepare a mother tincture in alcohol. To prepare the mother tincture, use one part of the oak buds to 10 parts of alcohol. When taken in the dose of 20 drops before a meal, the mother tincture helps in lowering blood pressure, fighting impotency as well as common physical and mental tiredness. A decoction prepared with tender oak leaves is drunk to encourage the flow of bile, purify the spleen as well as provide relief from irritable bowels. To prepare the decoction, use one leaf for one cup of water.
Usually, the outer bark and the sapwood or inner bark of the oak are collected from trees that are seven years old or above. After harvesting, the bark is sliced into smaller parts and then boiled in water for a few minutes. This herbal preparation requires one ounce (30 g) of the oak bark for every four cups (one liter) of water. This preparation is taken internally to heal poisoning due to lead, copper or mercury as well as bloody diarrhea. For best results, take a 10-day treatment with the preparation. The infusion may also be applied externally as a compressor to heal contagions in the anus or vagina, hemorrhoids, leucorrhea (a thick, whitish ejection from the vagina or cervical canal) as well as all different anomalous skin infections.