Interesting Facts about Oak Trees
Oak trees belong to the genus Quercus originating from the beech family that is also known as Fagaceae. The genus Quercus has about 600 species of oaks.
Oak trees are mostly deciduous except a few oak trees that are evergreen. They are tall and have a thick trunk. Scrub oaks do not grow very tall and have a thin network of branches.
Oak trees can grow well in temperate and tropical climates and are found in regions of Asia and North America. This article will deal with the characteristics of the three main types of oak trees - White Oak, Red Oak, and the Black Oak.
White Oak Trees
The White Oak tree also known as Quercus alba is native to North America. White oak trees can also be found growing in regions of Europe, Asia, and North Africa.
White oaks are deciduous or evergreen trees. The bark of the white oak tree is light gray and scaly. They are enormous trees that have thick trunks with crowns that are irregular in shape. The branches of these trees easily spread over a vast area.
The crowns of white oaks are pyramid shape when they are young but become broad and irregular as they age. The height of white oaks ranges from 60 feet – 100 feet in height. The trunk of the white oak tree can grow up to 4 feet in width.
Apart from the forest region, white oaks can be found growing near lakes, ponds, and streams. The leaves of the white oak tree have 5 - 9 rounded lobes and are about 4 - 9 inches long. The leaves of white oak trees turn red or brown during fall.
The White Oak trees provide shelter for many small animals in winter because the leaves often stay on even after they are dead and fall off during early spring.
The male flowers are greenish yellow in color and arranged in the form of catkins. The female flowers are small reddish spikes. The acorns of the white oaks are about an inch long and have a warty cap that covers only the top quarter of the corn.
The white oaks have a smooth, shiny bark with a tinge of purple.
Red Oak Trees
The Red Oak tree is also known as Quercus rubra and the Champion Oak Tree. Red Oaks are tall, sturdy trees. The height of the red oaks can range from 50 - 80 feet and have a width ranging from 2- 3 feet.
The bark of mature trees are dark reddish-brown in color and are broken up into wide ridges that have a flat top. The bark of old trees can become deeply ridged and furrowed as they age.
A unique feature of the bark of the Red Oak tree is that it has a shiny stripe at the center that extends throughout the length of the main trunk.
The Red Oak trees have stout branches arranged at right angles to the main stem. The twigs of the oak trees are thick, reddish to greenish brown in color without hairs. The winter buds are found clustered at the end of the twigs.
The leaves of the oak tree are simple and arranged in an alternate pattern on the twig. The leaves have about 7 – 11 pointed lobes and are 5 – 9 inches long. They have bristles on the edges of the lobes.
The upper surface of the leaf are dull green and the lower surface of the leaf is pale green.
A single tree produces both male and female flowers. The male flowers are arranged in the form of drooping catkins and are yellowish green in color. Female flowers are ovoid in shape and tiny. The blooming period occurs during mid to late spring.
The acorns of the Red Oak trees mature in two growing seasons. After pollination, the acorns of the red oak take about two years to develop. They are large, broad and rounded with a shallow, saucer-shaped cap.
Red Oak trees grow well in moist, well-drained slopes. During fall, the leaves change colors ranging from red, orange-red to a deep reddish brown. The wood of the red oak is thick and sturdy but it less durable when compared to white oak trees.
Red Oaks are great trees for landscaping purposes because they grow fast and can adapt to the growing site quickly.
Black Oak Trees
Black Oak trees are smooth and gray in color. They can grow to a height of 80 feet, but the trunk of the tree is tiny when compared to the height of the tree, measuring about 2 – 2 ½ feet in width. The inner bark of the black oak tree is an orange-yellow in color.
Leaves of the Black Oak tree are lobed and are 4 – 8 inches long. They have about 7 – 9 lobes that are pointed with bristles at the end. The upper surface of the leaf has a shiny green color, and the lower surface has a pale green color. The leaves of the black oak turn a color of bright red in the fall.
The Black Oak flowers during spring from mid-May. The male and female flowers are borne on the same plant. The male flowers are greenish-red in color and appear at the axil of the leaves of the previous year, and the female flowers appear at the axil of the leaves of the current year.
The acorns of the black oak tree are about ¾ inch long and take about two years to mature and start growing.
Main Differences Between the White Oak, Red Oak and Black Oak Trees
White Oak Tree
Red Oak Tree
Black Oak Tree
65 - 100 feet
60 - 90 feet
65 - 80 feet
5 - 9 rounded lobes, 4 - 9 inches long,does not have bristles
7 - 11 pointed lobes, 5 - 9 inches long with bristles on the tip
4 - 8 inches long, 7 - 9 lobes with bristles at the tip
3/4" - 1" long with warty cap that covers only the top quarter of the acorn
large, broad and rounded with a shallow saucer shaped scaly cap
3/4 inch long, half of the acorn is covered by a cap
Bark on the Trunk
gray in color broken by narrow fissures
dark reddish brown in color broken up by fissures
thick, black with deep furrows
Acorns of Oak Trees
Acorns are rich in protein, carbohydrates, fats and minerals such as calcium, phosphorous and potassium. The nutrient content in acorns differs across species.
Birds and animals consume acorns. Mammals such as pigs, bears, and deer consume a lot of acorns.
Oak trees are highly valued. In recent times, oak woodlands are on the decline. Conservation of oak trees is necessary to sustain wildlife in the forest and maintain a balance of nature's ecosystem.