"From little acorns grow mighty oaks"
Proverb, Geoffrey Chaucer, 1374
The mighty oak has been revered for centuries and is considered sacred by many civilizations. Oak trees symbolize strength, longevity, and endurance. The National Arbor Day Foundation designated the oak as the national tree of the United States. The supporters voted that this long-lived majestic giant tree was representative of the strength of the United States of America.
The average tree life span is approximately 100 years, but not so for the oak – these trees can live up to 1000 years (usually they live roughly 400 years). World-wide there are over 435 existing species and roughly 90 of those are considered native in the US. Our knowledge about the critical role that oaks play in ecosystems has gained much traction thanks to Dr. Douglas Tallamy, Professor in the Department of Entomology and Wildlife Ecology at the University of Delaware. His recent enlightening book, The Nature of Oaks – The Rich Ecology of our Most Essential Native Tree, is a wonderful read and explores the profound impact oaks have on the natural world. Every oak tree supports a whole community of living things that change throughout the year.
These magnificent trees are called a keystone species because they play a vital role in the food web of the ecosystem. Caterpillars that overwinter on oak trees are an essential source of food for overwintering birds. Oaks support the greatest number of Lepidoptera (butterflies & moths) which are a critical food source for birds and other wildlife.
All parts of the oak tree support biodiversity. The flowers are eaten by a host of insects, squirrels, bees, and butterflies. The oak mining bee feeds on the oak flower pollen and the list goes on and on. It’s impossible to note all the wildlife that depend on the oak tree since there are 2,300 species of wildlife and 1,178 invertebrates in this group. Oaks are also host to a huge number of lichen and fungi.
Another attribute of the oak tree is their function of soil stabilization. Their roots spread out three times beyond the spread of their crown. This important function helps to prevent erosion while conserving soil, improving soil fertility, and protecting groundwater quality. Fallen leaves (I do not like to refer to it as “leaf litter”) can last up to three years, providing essential cover for creatures that live in the soil. As a protective blanket, the leaves hold in moisture and return nutrition into the soil.
Try growing an oak tree from an acorn. It is easy to do and allows the oak tree roots to grow a full-size root system. Planting a large oak tree in the garden is riskier because the tree roots have been pruned and the tree goes into shock when planted. If grown in a pot too long, roots often become pot bound and then grow around in a circular fashion. If the plant can’t straighten the twisted roots, it can lead to roots choking themselves. The roots need to grow out from the center. You can also buy small oak trees which will turn into a healthier tree in the long run.
The white oak (Quercus alba) is one of the most widespread species in the eastern U.S. They are bountiful producers of acorns, serving as a considerable food source for wildlife such as blue jay, chipmunks, black bear and wild turkey. Throughout history, the acorns have been an important, nutritious food for humans as well. They contain bitter, astringent tannins that need to be leached before eating. Acorns can be made into flour or eaten as a delicious roasted nut – they taste a lot like roasted chestnuts. They should be gathered as soon as they begin falling from the tree. I enjoyed a native dinner produced by a friend who had created a food forest. The dinner included oak bread made with ground acorns.
White oak bark has a long history of use in medicine. Several North American Indian tribes valued it for its antiseptic and astringent properties. It was often made into a tea which was used to treat diarrhea, respiratory infections, and arthritis. The bark can also be dried and ground into a powder used topically to suppress inflammation and sooth irritated skin. It is thought that the tannins are responsible for the oak bark’s healing properties. White oak bark is available over the counter as capsules, liquid extract, tea, or powder. It is on the GRAS list which means that it is generally recognized as safe, but its use should be guided by a medical professional.
Try growing an oak tree from an acorn, it is especially fun for children to experience the process of growing such a significant tree.
Photo: The mighty white oak (Quercus alba)
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