An Oak is a tree or shrub belonging to the Beech family. Oaks have genus Quercus which covers about 600 species all over the world. Oak trees are characteristics of Northern Hemisphere. Oak trees are available in Temperate forests, Tropical forests and Mediterranean forests. They are great shade trees and many species of Oak have scenic fall colours. Fruits of Oak trees are called as Acron. Acron is technically a fruit that contains seeds but due to its hard outer layer, it is regarded as a nut. Acron is specific to the trees of Quercus Genus including Oaks.
Oak trees are a vital part of a forest ecosystem. The bark of many Oak trees is thick which protects them from forests fires. The trunk of Oak trees stores water for use during unfavourable conditions. Oak trees support a complex ecosystem with many species including humans. Oaks are susceptible to fungal diseases which rot the inner part of the plant. Oak trees are common in America, Asia, Europe, and North Africa. Mexico (North America) is the largest centre for Oak trees containing 160 species overall, following China (Asia) which holds approximately 100 species.
The Oak tree is officially the National tree of the United States of America (USA). Oak is one of the most loved trees in the world and is considered as a symbol of strength, morale, resistance and knowledge. In Greek mythology, Oak was a symbol of Zeus (The God of Thunder).
- Oak trees are very large in size. The average height of an Oak tree is 70 feet having a width of 9 feet. The branches of Oak trees can reach up to 135 feet in length.
- Due to their large size, Oak trees can absorb a great amount of water. An average Oak tree can absorb nearly 50 Gallons of water per day.
- Most Oak trees have lobed leaves but it can be serrated and flat in some species. Leaves are spirally arranged.
- Oak trees produce acrons from the age of 20 to 50 years. Each acron takes 6 to 18 months to mature. Young acrons contain Tannic acid which is toxic for cattle and can cause stomach ulcers and kidney failure. Tannic acids in the acron protect the Oak trees from fungi and insects.
- Oak trees are deciduous but few are evergreen, for example, Live Oak trees.
- The average life span of Oak trees is 200 years while some species survive up to a thousand years.
- Oaks produces both male (androecium) and female part (gynoecium) of the flower, also known as Bisexual or perfect flowers.
Types of Oak trees
There are 30 different types of Oak trees found all over the world. Overall, the 600 species of Oaks are categorised into two main types, that is, Red Oak trees and White Oak trees.
|Red Oak Tree||White Oak Tree|
- Leaf of Red Oak Tree
- Leaf of White Oak Tree
Live Oak Tree
- The Live Oak trees, also known as Evergreen Oak trees are the group of Oaks that do not shed their leaves throughout the year, that is, always remain alive. Live Oak trees keep their leaves until they die.
- As depicted by the name, these Oaks remain evergreen/live even when other Oak trees become leafless during the winter season.
- This evergreen foliage of Quercus Genus is common in North America, especially in the warmer area along the Atlantic coast from southeast Virginia to Florida, west along the Gulf Coast to Louisiana and Mexico, and across the southwest to California. They’re also present in Southern Europe and South Asia.
Pin Oak Tree
- Pin Oak, scientific name: Quercus palustris, is an Oak of Red Oak tree category. It is a popular landscape Oak due to its easy transplant and pollution tolerance. Pin oak is also commonly called swamp Spanish oak due to its tolerance to wet soil.
- Pin Oak trees can be easily distinguished due to the oval shape of their canopy.
- They’re fast growers and prefer clayey soil and bright sun. It prefers a minimum of 6 hours of daily unfiltered sunlight for a better outcome.
- Pin Oak trees are mainly found in eastern and central America. Other than America, they’re also native to the extreme south of Ontario, Canada and are even introduced in Australia, South Africa and Argentina where they’ve well adapted to the climate.
- Pin Oaks have glossy dark green leaves and the plant can reach up to a height of 60 to 70 feet.
- Pin Oak tree’s leaves turn scarlet and bronze during fall.
Water Oak Tree
- Water Oak Tree, scientific name: Quercus nigra, is also a plant of Red Oak family. It is native to North America and plays a great role in maintaining the ecosystem of New Jersey to Florida and west to Texas.
- This plant is short-lived compared to other Oak trees and is easy to nurture. The average life span of Water Oak tree is 30 to 50 years.
- The wood of Water Oak is comparatively soft. It is a weak wooded tree prone to many diseases. It is medium-sized, shade and ornamental landscape Oak tree.
- Water Oaks can tolerate the extreme quality of the soil. It prefers to thrive in wet and swampy areas but can also grow in drained, compacted soil.
- Water Oak tree is a copious producer of acrons due to which it is a part of food chains of a variety of nut loving animals including squirrels, raccoons, turkeys, pigs, ducks, quail and deer.
Oak Tree Root System
The roots of the oak trees are very strong and extend to a great distance underground compared to the tree canopy. Initially, when the roots arise from the acron, they grow as a Taproot system with primary root growing horizontally deep into the soil but later on, with the plant maturation, the Taproots gets transformed into an extensive root system.
Roots of the Oak trees spread up to 3 to 7 times the diameter of the tree’s crown, therefore they need a wide space, not just above the ground but under the ground as well to thrive to their fullest. They lie around 18 inches from the ground. Root hair present on the tip of the lateral roots helps in the absorption of water and nutrients from the soil which gets transported into the system. Oak tree roots require obstacle-free space under the ground with no underground pipeline, buildings or the roots of other large trees. If two Oak trees of same species are grown side by side, they can share a common root system by the process of grafting.
Roots of Oak trees grow best in the soil which is little acidic having a good amount of oxygen. The amount of water in the soil depends upon species to species. Some roots grow best in wet soil while some prefer drained, compact soil. Few species of Oak trees even survive in drought conditions, for example, native California oaks (e.g California white oak).
Roots of the Oak tree shows the symbiotic relationship between fungi named Mycorrhiza. A symbiotic relationship is a unique type of interaction between organisms of two different species which can be either harmful or beneficial to those species. In the case of Oak roots and Mycorrhiza, the fungi form a layer over the roots and protect the roots from other disease-causing fungi. Mycorrhiza also increases drought resistance capacity of the Oak trees and shares the nutrients they collect with the roots.
Oak Tree Root Diseases
Roots of Oak trees are susceptible to fungal diseases. Due to the fungal attack on some roots, the roots get rotten and the infection reaches up to the tree trunk. Due to the fungal infections, the tree gets cut off of the water and nutrients supply and die eventually. Fungus feeds on the roots of the Oak trees. Various anti-fungal sprays are available to keep the Oak trees from getting the infection.
Uses of Oak Tree
- Natives of North America used Red Oak for treating ailments and wounds. Oak tree can also be used to treat Diarrhoea, asthma and can be used as an antiseptic.
- The bark of the Oak tree contains tannin and this tannin is used for making tannin leather from hundreds of years.
- One of the most important uses of the Oak tree is for shade. Due to their large crown size, they’ve been used as shade providers especially during summer seasons.
- Oak trees hold great importance in an ecosystem as they are food providers and habitat for various animals and bird species.
- White Oak wood is popular in timber trade as its wood is highly durable and is used for furniture, flooring and making cabinets in the houses.