Oaks and acorns

A giant pin oak tree still stands in the yard of the house where I grew up. It likely was planted when the house was built, and the house is 118 years old. The mighty oak is a resilient and long-lasting tree. The proverb "from little acorns come mighty oaks" reminds us that great things can arise from humble beginnings (https://libanswers.nybg.org). Oak trees have been associated with patriotism, strength, and courage, and the tree's fruit, the acorn, symbolizes prosperity, good luck, and endless potential. Oak trees have evolved over 56 million years, into 435 species growing on 5 continents. Acorns have been food for people throughout the world for thousands of years, including Native Americans, who ground the nuts into flour. In the 4th century, ink was made from oak galls (growths formed from wasp eggs). About 90 oak species exist in North America, and 60 species are native to the U.S. (arborday.org). Birds, insects, spiders, and mammals (2,300 species) rely on oak trees for food, shelter, and raising young (https://www.woodlandtrust. org.uk). Fungi also thrive in and around oaks. Some birds fly thousands of miles each spring to feed on caterpillars in the canopies of oaks, where almost 900 caterpillar species reside. Acorns are full of fats, protein, and carbohydrates, making important food for many birds and animals. White oak and English oak (closed-grain woods) contain tannins, and tyloses (natural plastic type structures), which give the wood disease resistance and water resistance. These woods were ideal for shipbuilding. Oak limbs provided just the right angles for the Vikings' ship frames. The hull of the U.S.S. Constitution, "Old Ironsides," was constructed from Live oak, (the strongest wood of all oaks) which repelled the British cannonballs during the War of 1812! (nps.gov). White oak barrels are the choice for aging whiskey, bourbon, and wine, slowly releasing tannins which impart a character tasting similar to vanilla and licorice. The oak tree is the national tree of the United States, as well as many other countries, such as Bulgaria, Cyprus, France, Germany, Poland, Romania, and Wales. Over half of the oak species in the U.S. are found in Texas, due to the diversity of growing conditions. The oak species is native to all states in the U.S. except Idaho, Alaska, and Hawaii. Oak trees have a juvenile period of about 20 years until producing a crop of acorns. Once producing a crop, acorns of white oak trees mature in 1 year, however, acorns of black oaks and red oaks require 2 years to mature. Many oak trees don't produce a large crop of acorns until approximately 50 years old, with peak production from 50-80 years. The average 100-year old oak tree produces 2,200 acorns a year, but only 1 in 10,000 grows into a tree. Mature heights of oaks range from 35 feet to more than 100 feet, growing fastest in the first 10-15 years. A canopy spread of 60-100 feet requires that this tree has space to grow. The average lifespan of an oak tree is 100-300 years, but varies according to the species of oak. The oldest oak tree, the Jurupa Oak, located in California, is estimated to be 13,000 years old (https://www.washingtonpost.com). The white oak (Quercus alba) is native to Ohio, as well as the entire eastern half of the U.S. The chestnut oak (Quercus prinus), bur oak (Quercus macrocarpa) and swamp white oak (Quercus bicolor) are also native to Ohio. The white oak is the most well-known oak tree, and the most commercially valuable of all the oaks (https://mdc.mo.gov). Oak wood has a density of 0.75 grams per cubic centimeter, and pine wood density is 0.43 grams per cubic centimeter, making oak the hardest, most durable, and fungal-resistant wood for making building products and furniture. Have you noticed some oak trees "hold on" to their leaves through winter until new spring growth forces the leaves to fall? This is known as marcescence. Although not completely understood, one theory is that deer, moose, and other animals like eating the new leaf buds, but the buds are surrounded by bad-tasting leaves, possibly deterring bud damage. Leaves remaining on oaks direct more snow to the roots, and the leaves falling in early spring create mulch at the perfect time. The oak leaf litter supports millions of millipedes, slugs, woodlice, and also fungi. Live Oak (Quercus virginiana) got its common name due to keeping its leaves through the winter. According to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, about 31% of the 430 types of oak in our world are threatened with extinction. Sixteen species of oaks are classified as Critically Endangered, Endangered, or Vulnerable on the list, and 4 species listed Near Threatened. Threats to oak species include drought, development, agriculture, and pests and diseases (native and non-native). In addition to the threats to oak trees, seed banks cannot store acorns with conventional methods, so The Morton Arboretum is part of a network of organizations assessing and conserving oak trees, and propagating cuttings and acorns (internationaloaksociety.org). The information will be utilized by the Global Tree Assessment to help evaluate the threat level of over 60,000 species of trees in the world. All trees provide incredible environmental benefits, and are important to our physical and mental health. One acre of trees can absorb 6 tons of carbon dioxide every year. The University of Pennsylvania has even dedicated a new field of study called veteran tree care management (lsu.upenn.edu). It is vital to care for these live treasures. If space allows, consider planting trees—especially oak trees!