Interesting Facts on Oak Trees

Oak trees can be deciduous or evergreen.

The oaks are a very successful group of flowering trees and shrubs that are included as part of the beech family, Fagaceae. Distinguished by a distinctive seed called an acorn, the oak grows across the Northern Hemisphere in many different habitats. Overall, this type of tree varies in size from a small, desert, evergreen shrub to a towering, massive, deciduous tree that can live close to 1,000 years.

Number of Species

Overall, there are hundreds of species of oaks, all packed into one genus that goes by the name of Quercus. Despite the fact that there are so many kinds of oaks, this tree can be distinctly divided into two subgroups. Known as the white and red oaks, these divisions are easily separated by the shape of the leaf. In general, white oaks have lobed leaves, while those of the red oaks are serrated or bristle-tipped. Most oaks with oval-shaped leaves fall into the white oak subheading.

Live Oak

The live oak is evergreen, which means the leaves stay on the plant all year long. All the leaves are replaced over time (usually annually), so the tree never goes into a dormant state. However, the hard brittle leaf that falls to the ground after it dies plays an important role in helping the tree survive. It does this primarily by creating a thick layer of leaves that prevents other plants from growing underneath. This ground cover discourages any plant competitors that might quickly grow quickly and steal the available sunlight.

Oak Leaves

In some Northern species, the oak leaves remain on the branches long after they have changed color. These leaves are a special treat to squirrels and other wild animals that will use the oak leaf to line the nest during the course of a long, cold winter. The leaf of the oak has excellent insulating value and will enable these pesky rodents to survive a winter without hibernating. Some outdoorsmen know about the insulating value of the oak leaf and will use the leaf to make a winter blanket to be placed inside an emergency shelter.

Cork Oaks

One tree, Quercus suber or cork oak, produces the natural cork material for stopping and sealing bottles of wine. The tree is native to the Mediterranean countries of southern Europe and northern Africa with Portugal producing half of the world's supply of cork. The cork oak naturally produces an extra thick layer of bark, which can be cut away periodically during the course of the life cycle of the tree. The first cutting is done at age 25 and yields the largest amount of cork. The removal of the bark does not harm the tree and is repeated every nine years, for about 100 years.

Acorns

Since an acorn usually drops straight to the ground, the new seed needs some help, if it is to find a new home away from its giant parent. In the wilds of North America, jays and squirrels are the main agent of seed dispersal for the oaks. Each animal has behavior that consists of gathering small quantities of acorns and placing each quantity in a separate cache. This stash is then visited during the winter as a source of stored food. On the occasion that the squirrel or jay does not consume all its acorns, the new seed may sprout in the spring and produce a new plant.

References

• Cork in Portugal: Cork Oak
• Science Daily: Researchers Tackle The Nutty Truth On Acorns And Squirrels
• USDA Forest Service: Quercus Virginiana

Resources

• University of Kentucky Arboretum: Red and White Oaks