Exploring the World of Oaks
Exploring the World of Oaks
Oaks are beautiful, sturdy trees that can last for generations. The oldest living oak is the Pechanga great oak in California. Experts estimate the tree to be at least 2,000 years old! Oaks are in the Fagaceae family, and the genus Quercus is comprised of roughly 500 species worldwide, with about 60 growing in the United States. There are two main groups of oaks found here in the Midwest, red oaks and white oaks.
Comparing the Groups
Oaks are split into two major groups based on the physical attributes of the tree and the cellular structure of the wood. The physical attributes of the groups do have exceptions just like everything else in the plant world.
The biggest difference you will notice between the two groups is their leaf shapes. Red oaks tend to have pointed leaf lobes while white oaks usually have rounded lobes. White oaks fruiting cycle is different as well. Acorns on white oaks mature after one year, but acorns produced on red oaks take about 2 years. Other attributes like twig and bud form, bark, and acorn shape can be used to differentiate between the two groups as well, with some practice.
To touch briefly on the cells of the wood, white oaks have tyloses which are outgrowths of certain cells that essentially block nutrient transportation vessels (xylem and phloem) when the tree is injured or diseased. Blocking these vessels helps slow down the spread of decay and disease. Red oaks do not have these which is why they succumb to oak wilt quicker than the white oaks once infected.
Wildlife Value of Oaks
With many oaks being native to our region they are a vital resource for wildlife. They support over 500 species of insects including various moths, butterflies, and wasps. The high insect activity on these trees attracts birds, frogs, and small mammals. With the large size of these trees and the consistent food they produce, many of those birds and small mammals will build their nests and burrows around these trees. Oaks also produce acorns which are an important food source to deer, opossums, blue jays, and more.
Oak Species and Cultivars
We carry multiple species of oak in both the red and white groups to match your needs. Below is an overview of what species we have and some of their attributes.
- Red Oaks
- Northern Red Oak
- Northern Red Oaks can grow to be 60-70’ tall and wide. They require full sun and prefer moist, well-draining soils. They can tolerate dryer sites and clay soil. In the fall the foliage turns a deep red.
- Shingle Oak
- Shingle oaks are one of the exceptions of red oaks having pointed leaves. Their leaves are oblong with no distinct lobes and turn orange/brown in the fall. Shingle oaks grow to be 50-60’ tall and wide and enjoy full sun. They prefer moist, well-draining soils and can tolerate some drought once established.
- Northern Red Oak
- White Oaks
- Swamp White Oak
- Swamp white oaks enjoy moist, well-draining soils and can tolerate wet sites, occasional flooding and clay soil. They can grow to be about 50-60’ tall and wide. Swamp white oaks foliage is bicolored with a deep green top and a silvery green underside. In fall the leaves turn orange/brown.
- Bur Oak
- Bur oaks have some of the most corky and furrowed bark of the oaks, even on the twigs giving them almost a winged appearance at times. Bur oaks can grow to be about 55-60’ tall and 45-50’ wide and prefer full sun. They grow best in moist, well-draining soils but will tolerate occasional drought and clay soil. In fall the foliage turns brown.
- Chinkapin Oak
- Chinkapins are another oak with a unique leaf shape. They are coarsely toothed which can appear either rounded or pointed. They can grow to be 50-60’ tall and wide. They prefer full sun and moist, well-draining soil. They can tolerate dry sites and clay soil. In fall the foliage turns bronzed red.
- Swamp White Oak
Oaks are not only beautiful shade trees, but they are also important to our wildlife and natural habitat. Message us on Facebook or give us a call for more information on our oaks.
