Why is species diversity important?
Species diversity is a common measure of a community forest's overall health. In a sense, increasing species diversity prevents us from "putting all our eggs in one basket" and prohibits any single insect or disease from destroying a community's entire forest resource. Pine wilt, Dutch elm disease and the approaching emerald ash borer (EAB) all reinforce the importance of species diversity. In fact, forestry experts recommend that no single species make up more than 10 percent of the entire community forest resource.
ReTree Nebraska's Good Trees for the Good Life
Because one of the goals of ReTree Nebraska is to increase species diversity in community forests across our state, ReTree Nebraska is announcing "Good Trees for the Good Life." This list includes trees that grow well in Nebraska, but are often under-utilized. Starting in 2008, a tree species will be added each year to the previous selections until 2017 creating "Eight for 2008," "Nine for 2009,"..."Seventeen for 2017."
2017 Selection Turkish filber (Corylus corlurna) & other nut trees: hickory, chestnut, pecan, buckeye & *walnut
(Corylus colurna, also called Turkish tree hazel) pyramidal shape in youth, eventually rounded; scaly bark; handsome dark green foliage and interesting winter catkins; doing well in Lincoln, North Platte. The availability of Turkish filbert is very limited so planting other nut tree species may be more practical. For more information, visit retreenebraska.unl.edu/plantingfordiversity. *Black walnut is susceptible to a potentially serious threat called “thousand cankers disease.” Other walnut species are less susceptible to this disease.
Nutty About Nut Trees -
Reprinted from SIMPLY TREES for October 2015 by Justin Evertson, Nebraska Forest Service
When someone is said to be a “tree nut,” it means they really like trees and are probably a bit obsessive about them. If you’re not that into trees, you may not want to sit by a tree nut at a social function. You’ll likely hear that some trees can reach over 300 feet tall and that some are over 5,000 years old. And you’ll probably hear quite a bit about many of the over 200 different kinds that can be grown in our region—a region once dominated by prairie.
I’m a tree nut. In fact, I’m especially nutty about nut trees, including hickories, pecans, walnuts, buckeyes, chestnuts and just about any other tree that could produce a fruit that a squirrel would love (most tree nuts are not squirrel nuts). This little article celebrates hickories—the king of the nut trees. Though they’re seldom encountered in the planted landscape, hickories most definitely deserve greater attention and planting.
The word hickory derives from the Algonquin or Powhatan word pohickery. Their scientific name Carya is Greek in origin and means “nut.” Hickory species occur throughout the eastern U.S. and most were important food or timber sources for Native American tribes and early settlers. There are five hickory species native to the Midwest (two are native to Nebraska’s eastern hardwood forests) and they all have very descriptive common names, usually relating to their nuts or their bark:
Bitternut hickory (Carya cordiformis). As its name implies, this hickory has a small, bitter-tasting nut. This is Nebraska’s most common native hickory occurring in oak-hickory woods from the South Sioux City area southward to Jefferson County. It’s a fast-growing hickory that can reach up to 70 feet tall and 30-40 feet wide. Bitternut turns a nice yellow in the fall and is easily recognized in the winter by its smooth young bark and sulfur-yellow buds.
Shagbark hickory (Carya ovata): This hickory is known for its “shaggy” bark, which exfoliates in long strips as the tree matures. Unlike the bitternut, the shagbark has a relatively tasty nut favored by a wide variety of forest birds and animals, as well as humans. The tree has large, deep green, compound leaves that can turn a bright yellow in fall. The shagbark reaches 50-60 feet tall and is relatively abundant on rich soils in Nebraska’s oak-hickory woods from the Omaha area south to the Rulo Bluffs.
The shellbark hickory (Carya laciniosa) is a close cousin of the shagbark hickory, possessing the same “shaggy” bark. Sometimes called the kingnut, shellbark has the largest nuts of all the hickories, which while still in the outer husk are about the size of a baseball. The nuts are sweet and tasty and highly prized by both humans and wildlife. Shellbark can grow quite large, from 60 to 80 feet tall and up to 50 feet wide and is one of the longest-lived hickories. Though not native to Nebraska, there are many impressive specimens in southeastern Nebraska. Mockernut hickory (Carya tomentosa) is perhaps the most common hickory of the eastern U.S. Its common name refers to the relatively large nuts that have thick shells and very little nut meat inside, thus “mocking” those that try to eat them.
Mockernuts grow straight and true, up to 60 feet tall or more, and can be very long-lived, with some specimens known to be over 500 years old.
Northern pecan (Carya illinoinensis) is related to bitternut hickory, with the two species sometimes producing naturally-occurring hybrids where they occur together. Unlike the bitternut, the pecan has a very tasty nut that has become an important food crop across the world. In fact, the pecan is the most abundantly harvested food crop native to North America. Almost every other modern food crop originated on other continents. Pecans make great shade trees with many in eastern Nebraska reaching up to 80 feet tall and 60 feet wide.
Most hickories possess a thick and deep-growing taproot that makes them somewhat difficult to transplant and which also makes them relatively rare in the nursery trade. That’s too bad. The hickories are great trees in a lot of ways: they provide good shade; they’re generally long-lived; they provide good lumber; they support a wide variety of important wildlife; and they often have tasty nuts.
Do yourself a favor and seek out a hickory or two for planting in your own yard. It can be as simple as going out into the native woods and harvesting some nuts that the squirrels have missed. Alternatively, many on-line nurseries offer hickories, including the Nebraska Statewide Arboretum. It is generally recommended to plant small seedlings. Finally, a great organization to learn all about nut trees, including grafting, planting and harvesting is the Nebraska Nut Growers Association: http://www.nebraskanutgrowers.org/. Talk about a great bunch of tree nuts!Printable resources:
Finding "17 for 2017" Species
To find one or all of theses tree species, check ReTree's informational listing of ReTree-participating nurseries here.