The oak tree family consists of more than 600 species of trees and shrubs that produces durable and attractive lumber wood. The oak is a common symbol of strength and endurance. It is the national tree of the United Kingdom, Germany and the United States. Many oaks have attractive fall color and provide good winter interest with their twisted branches and ridged bark.
The oak tree is a deciduous tree that comes in many variations. Oak trees are organized into three main groups, based on leaf shape: red oaks, white oaks and live oaks. An oak tree's height can reach up to 100 feet, with the spread of the canopy of a full grown oak ranging from 85 to 135 feet or more in diameter.
Historically, the oak was considered sacred by many civilizations, including the ancient Greeks and Romans, who revered the oak. The Roman doctor Galen first used oak leaves to heal wounds. The oak tree's longest association, however, was known to be with the British Isles. The Druids considered oaks to have medicinal and mystical significance. An oak sprig was inscribed on English coins for centuries, and King Arthur's round table was said to be made from one piece of ancient oak.
Most oak trees require little to no cultivating and care during their lifetime. Oak trees have deep root systems and can draw more than 50 gallons of water per day. Oaks thrive in full to partial sun, but they are shade tolerant when young. Along with the pin oak, red oak trees are one of the few oaks that are important shade trees in the landscaping industry, noted for their autumn color and rapid and vigorous growth rate.
Oak trees are hardy trees but can be susceptible to several diseases and pests. Though the tree may overcome several diseases without damage, sudden oak death can cause the death of an oak tree in just a few weeks. Oak wilt is an aggressive disease that affects many species of oak. It is one of the most serious tree diseases in the eastern United States, killing thousands of oaks each year. When one tree becomes infected and dies, the fungus spreads through connected root systems, killing more trees.
Oaks are hardwood trees with dense and rigid wood, which makes it an ideal material for building construction, furniture, railroad ties, beams, flooring, barrels, tool handles and shipbuilding. In North America, the wood of the white oak is often used for the construction of barrels for aging wine. Oak has been recognized throughout time for its durability and was used by the Iroquois for making canoes and mortars.
White oak bark contains tannin, which can be applied to insect bites or taken internally as an intestinal astringent. Oak bark is available as tablets, capsules, extracts and tinctures. Also, the tannin in oak bark is used in leather preparation.
Oak trees are fruit-producing trees that develop acorns. Most oak trees do not produce acorns for approximately the first 20 years, but some trees wait for more than 50 years. Acorns are a source of food for wildlife and were used as fodder for farm animals in the past. Flour made from ground acorns was also a part of the diet of Native Americans.