Today, there are nearly 400 species of oak trees that exist around the world. They can grow in a variety of habitats ranging from wet lowlands to high dry mesas and from seacoasts to high mountain slopes.
Oak trees may be either deciduous or evergreen and are widespread in the North Temperate Zone. Around springtime, before the new leaves appear, the tree flowers due to the large quantity of pollen that is shed into the wind. Oak trees have clustered flowers and are identified by their distinctive fruit, the acorn, which has a cup-like structure called a ‘cupule’. Depending upon which species they belong to, trees may have spirally arranged leaves with a lobed margin, serrated leaves or entire leaves with a smooth margin.
Different Types of Oak Trees
It is a massive, shady tree with evergreen leaves, which are bright olive-green initially but change to a glossy, dark green when mature. The tree belongs to the species Quercus virginiana and grows well in clay, sandy and loamy soils. With a pH ranging from 3.7 to 7.0, the tree can tolerate a wide range of moisture conditions. It grows up to a height of 30 to 40 feet and spreads up to a width of 40 to 60 feet, and thus, requires a large area for the branches and the roots to grow.
It has glossy, dark green summer leaves which change to bronze or red color in the fall. It bears a light brown acorn which is nearly ½ inch long and wide. It belongs to the species Quercus palustris and grows well in sandy, loamy or clay type of soils. The branching nature of the tree is very unique as the upper branches are ascending, the middle ones are horizontal, and the lower branches are drooping. It grows up to a height of 60 to 70 feet and spreads up to a width of 25 to 40 feet.
It is known for its strength and brilliant fall color, and belongs to the species Quercus rubra. It grows best in well-drained soils, has moderate water requirements, and is tolerant to salty and alkali soils. It grows up to a height of 50 to 60 feet and spreads up to a width of 45 to 55 feet. It has massive, rounded, ascending branches that tend to droop low. The fall color of the leaves varies from yellow-brown to russet-red and bright red.
It is a majestic tree that lasts for generations and belongs to the species Quercus alba. It grows well in deep, moist, well-drained, acid soils and has moderate water requirements. The fall color of the leaves vary from bluish-green to reddish-brown and its fruit, the acorn, serves as the best source of food in the wild. It grows up to 60 to 100 feet in height and spreads up to 50 to 90 feet, and hence, requires plenty of space to mature properly.
Sawtooth oak tree is a fast growing shade or lawn tree that belongs to the species Quercus acutissima. It has moderate water requirements and tolerance to salty and alkali soils. It is a highly priced oak tree because of the short time it takes to produce acorns. The color of the leaves vary from yellow to golden brown in the fall and brilliant golden yellow in spring. It grows up to a height of 40 to 50 feet and may spread up to 50 to 60 feet.
Belonging to the species Quercus macracarpa, it is a slow-growing tree with a bulky trunk, sturdy branches and lives a long life. It is in demand for hedges or fences of trees to lessen the force of the wind and reduce erosion. Its strong wood is used for timber. Autumn colors include yellow, yellowish green or yellowish brown. The leaf lobes are deep and rounded and leaf length is 4-10 inches. The fruit is an acorn that ripens during fall and is partially covered up by a laciniate cup.
Willow oak (Quercus phellos) trees grow relatively fast about 2″ a year, has restrained water requirements, and tolerates salt and alkali soils. Leaves of this tree are yellow to yellowish-brown. This tree can withstand heat, shortage of rainfall, air pollution, standing water, and is mostly found on streets, in parks, and around residential areas.
Some other types of oak trees include: water oak, overcup oak, scarlet oak and chinkapin oak. These trees have always been commercially valued for their hard, strong wood which has a multitude of purposes including furniture and flooring. They can also be used for the purpose of landscaping.