Oak Trees

Description

Oak is the common name for many acorn-producing trees and shrubs that are members of the beech, or Fagaceae, family. Oak trees are classified as members of the genus Quercus, a Latin word said to be derived from a Celtic word meaning "fine tree." Worldwide there are more than 600 different species of oak. They thrive across the Northern Hemisphere in China, Japan, Europe, the British Isles, and in all of the continental United States except for Alaska. More than half of the 600 species are native to North America. Yet only about 60 varieties grow north of Mexico. In the forests of northern areas that have short summer growing seasons and long winters, such as Canada, northern Europe, and Siberia, varieties of oak are very scarce.

The oak family is a diverse group of trees and shrubs, influenced by climatic and environmental changes. Recent studies indicate that global warming contributes to oak dieback by speeding up the reproduction of beetles and fungi that attack oak trees. There are oaks that grow to heights of about 100 ft (30.5 m), while other types never grow larger than a small shrub. In warmer climates, oaks are evergreens, keep their leaves all year long, and are often used as ornamental trees in parks. In colder climates, they usually drop their leaves in autumn.

Many of these deciduous oaks have leaves that turn brilliant gold or scarlet in the autumn. In spring small, yellow green flowers appear. The male flowers hang in clusters called catkins and have profuse amounts of pollen. This oak pollen is carried by the wind to fertilize female flowers that produce acorns. Oak trees grow very slowly. In 80 years, it's estimated that one will grow to no more than 2 ft (0.6 m) in diameter. Oaks do not even produce acorns for their first 20 years, but they live a very long time. Average life expectancy for most oaks is between 200 and 400 years, and there are oak trees over 800 years old that are still alive.

Oaks are divided into two basic categories: white and red. The leaves of most of these are characteristically lobed, and depending upon the variety, can have anywhere from five to 11 lobes. Historically, the oak has been considered sacred by many civilizations. Abraham's Oak, the Oak of Mamre, is thought to be on the spot where the bible states Abraham pitched his tent. Legend states that anyone defacing this tree will lose their firstborn son. Both the ancient Greeks and Romans revered the oak, but its longest association has been with the British Isles. The Druids considered it to have both medicinal and mystical significance. For centuries, an oak sprig was inscribed on English coins. Legend states that King Arthur's round table was made from one gigantic slice of a very ancient oak tree. Oak has been used as a medicine since the ancient Greek and Roman times. The famous Roman doctor Galen first used oak leaves to heal wounds.



The American white oak, Quercus alba, and the English oak, Quercus robur, have bark with similar healing qualities. Oak bark contains saponins, tannins, calcium oxalate, starch, glycosides, oak-red, resin, pectin, levulin, and quercitol.


General Use

Oak wood as timber is prized for its strength, elasticity, and durability. It is ideal for making furniture, barrels, railroad ties, and in the past, ships. Oak acorns are a source of food for wildlife and have been used as fodder for farm animals in the past. A flour made from ground acorns was also a part of the diet of Native Americans. The tannin in oak bark is used in leather preparation. Cork is made from the bark of some species that grow only in Spain and Portugal.

Recent advances in molecular genetics have shown that DNA from samples of oak can be isolated and analyzed. This type of analysis has a variety of potential applications in archaeology and forensic investigations.

Oak used to make wine barrels has been found to increase the antioxidant activity of wines aged in the barrels as well as adding a distinctive aroma to the wine. The increase in antioxidant activity can be measured by a new technique known as electron paramagnetic resonance, or EPR.

Oak bark is used in medicine as a bowel astringent to treat diarrhea and as an anti-inflammatory gargle for soothing sore throats. It can be used topically for such skin inflammations as dermatitis, as an enema for hemorrhoids, or as a douche for vaginal infections and leukorrhea. A study in 1980 showed some evidence that oak bark may prevent kidney stone formation and act as a diuretic. A 1990 Russian study demonstrated that oak bark had antibacterial activity against Staphylococcus. One study in 1994 showed that oak bark could reduce serum cholesterol levels in animals.

American Oak Tree

American Oak Tree leaves:



Red Oak tree:
In Britain this is by far the most commonly planted American oak.
It comes from eastern North America from Nova Scotia to Georgia.
It was extensively used as a forest tree in Europe in the nineteenth century and in Britain after 1920. The tree grows faster than native oaks in most of the country, but it requires full light and will not tolerate close spacing. The wood is not durable outside without preservative treatment. In some seasons there is good red and orange autumn foliage colour.

Size: A large, deciduous tree to 75' (23m) tall.
Environment: Full sun. Well drained, acidic, sandy loans are best. Withstands urban conditions well.
Key Features: Grows rapidly for an oak.

The Weeping Willow Tree (Sauce Llorón)

This Picture was taken in St James Park by the water pond in March 2005. These willow trees can be found where there is plenty of water. Finding this willow tree in St. James Park was truly a sight to behold. Its pointed leaves and its light elegant foliage flows look like tousled hairs in a graceful flourishing poise, such is the beauty of the weeping willow tree.

Ash tree (El Fresno)

Fraxinus, common name Ash, is a genus of usually medium to large trees, mostly deciduous though a few subtropical species are evergreen. Genus Fraxinus are the true ashes, and are in Oleaceae, the olive family, along with olives and lilacs.



The Ash tree sheds all its leaves in Autumn.
It is a deciduous tree.



This year you could see the Ash trees go yellow as soon as Autumn started.
They are so beautiful!!! :)



The Ash tree in Summer is full of green leaves.




Ash tree seeds

The seeds, popularly known as keys or helicopter seeds, are a type of fruit known as a samara. The genus Fraxinus contains 45-65 species.




The leaves are opposite (rarely in whorls of three), and mostly pinnately-compound, simple in a few species.



The tree's common English name goes back to the Old English æsc, a word also routinely used in Old English documents to refer to spears made of ash wood.







The wood is hard (a hardwood), dense, tough and very strong but elastic, extensively used for making bows, tool handles, quality wooden baseball bats, hurleys and other uses demanding high strength and resilience.

It is also often used as material for electric guitar bodies and, less commonly, for acoustic guitar bodies, known for its bright, cutting tone and sustaining quality.

Selection of trees

Photosynthesis

Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae (Kingdom Protista). Plants need only light energy, CO2, and H2O to make sugar. The process of photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis.
Photosynthesis takes place primarily in plant leaves, and little to none occurs in stems, etc.

Photosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of Bacteria, but not in Archaea.
Photosynthetic organisms are called photoautotrophs, since it allows them to create their own food. Photosynthesis is crucially important for life on Earth, since as well as it maintaining the normal level of oxygen in the atmosphere, nearly all life either depends on it directly as a source of energy, or indirectly as the ultimate source of the energy in their food.

The parts of a tree

Tree roots anchor the structure and provide water and nutrients.

The parts of a tree are the roots, trunk(s), branches, twigs and leaves.

Tree stems consist mainly of support and transport tissues (xylem and phloem). Wood consists of xylem cells, and bark is made of phloem and other tissues external to the vascular cambium.

Trees may be grouped into exogenous and endogenous trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of trees (all conifers, and almost all broadleaf trees), grow by the addition of new wood outwards, immediately under the bark.
Endogenous trees, mainly in the monocotyledons (e.g., palms and dragon trees), but also cacti, grow by addition of new material inwards.

The roots of a tree are generally embedded in earth, providing anchorage for the above-ground biomass and absorbing water and nutrients from the soil.
It should be noted, however, that while ground nutrients are essential to a tree's growth the majority of its biomass comes from carbon dioxide absorbed from the atmosphere (see photosynthesis). Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for sunlight. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight.

Trees

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter (30 cm girth). Woody plants that do not meet these definitions by having multiple stems and/or small size, are called shrubs. Compared with most other plants, trees are long-lived, some reaching several thousand years old and growing to up to 115 m (379 ft) high.


Trees are an important component of the natural landscape because of their prevention of erosion and the provision of a weather-sheltered ecosystem in and under their foliage. Trees also play an important role in producing oxygen and reducing carbon dioxide in the atmosphere, as well as moderating ground temperatures. They are also elements in landscaping and agriculture, both for their aesthetic appeal and their orchard crops (such as apples). Wood from trees is a building material, as well as a primary energy source in many developing countries. As of 2005, there were approximately 400 billion trees on Earth, about 61 per person.