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Species Guide |
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| The following species are discussed in this guide: | |||||||
| hackberry Celtis occidentalis |
American elm Ulmus americana |
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| slippery elm Ulmus rubra | |||||||
| Species | hackberryCeltis
occidentalis |
| Species Name | of the west |
| Sites and Soils | hackberry occurs on rich alluvial soils of river bottoms and stream banks, and on upland dry sites, especially on limestone-derived soils. |
| Ecology | Hackberry is typically an intolerant disturbed site species. However, it is a very variable species, and has a broad range of tolerance and site requirements. Hackberry is found on bottomlands and river banks, and on limestone uplands. On bottomland sites, it occurs as a scattered tree in mixed hardwood stands. Its associates include riverine species such as American elm, cottonwood, American sycamore, green ash and sweetgum. On limestone sites, its associates include Osage-orange, blue ash and bur oak. Hackberry may form pure stands in hedgerows on upland limestone sites. Hackberry is very susceptible to fire damage, but regenerates quickly on burned sites. |
| Life History | Hackberry regenerates from seeds and stump sprouts. It flowers in early spring, and bears seeds which are dispersed in late summer or winter. The fruits are attractive to birds, which disperse them considerable distances. Seeds enter the seed bank, and can persist for many years. Germination occurs in spring when soil moisture is adequate and there is ample sunlight. |
| Interactions | VA mycorrhizal; wind and insect pollinated. Hackberry has numerous leaf pests and pathogens. Typically, leaves look pale and ragged by late July, as leafhoppers, nipple gall wasps, fungi and other organisms assault the leaves throughout the growing season. |
| Status | Abundant; stable |
| Range | Northern half of Eastern Deciduous Forest, but more common in the midwest. On limestone sites in the northeast. Disjunct populations in the deep south. |
| Kentucky status | Abundant; stable. |
| Kentucky range | Entire state. Most abundant in Mississippi River Valley and Bluegrass. |
| Uses | Hackberry is a low value species, used in the Mississippi River Valley along with other bottomland species, for pulp and rough lumber. |
| Ornamental use | Occasionally used, and some genotypes are attractive. Foliar diseases limit the use of the species. |
| Notes |
| Species | American elmUlmus
americana |
| Species Name | of America |
| Sites and Soils | American elm is a disturbed site species, especially of river bottoms, but also abundant on upland disturbed sites where spring soil moisture is adequate. |
| Ecology | American elm was one of the most important disturbed site species of the entire Eastern Deciduous Forest. Intermediate in tolerance, American elm occurred on a huge variety of sites and successional positions. It was especially characteristic of river bottoms, creek banks and swales. In agricultural areas, it was abundant in hedgerows and any unused land. The characteristic vase shape of open-grown elms could be seen everywhere in farmlands of the east. American elm is still a fairly common tree, but the numbers have been drastically reduced by Dutch elm disease and elm phloem necrosis. Large trees are particularly uncommon |
| Life History | American elm flowers in very early spring, sometimes on warm days in winter. Pollination is by wind and insects (?). Seeds are dispersed by wind or water in late spring, among the earliest seeds dispersed. Germination occurs immediately on moist mineral soil, and seeds do not enter the seed bank. Early growth is rapid, but slows quickly with age. Prior to the epidemic of Dutch elm disease, elms typically lived to 200 years, and often twice as long. Now, it is not common to find elms living more than 30 years, except in cities where they receive care, including injections of fungicide. Recruitment of seedlings is still fairly good in many areas, so that young American elms are fairly common. In most areas, slippery elm is now more common. |
| Interactions | VA mycorrhizal; wind and insect pollinated. I have seen native bees, honeybees, and beetles on elm flowers and , but I am unsure what the major pollinators are. Fruits are favored by songbirds. The disease complex that besets American elm is further described on the Pathology page. |
| Status | Common, but drastically reduced from its former abundance by disease |
| Range | Eastern Deciduous Forest, including Plains Extension. |
| Kentucky status | Common; increasing since introduction in the 19th century. |
| Kentucky range | Entire state. Most abundant in Mississippi and Ohio River Valleys and their tributaries. |
| Uses | American elm has beautiful wood, often highly figured because of its interlocking grain. However, this grain property also makes the wood difficult to work. Elm is a minor furniture wood, but the supply of quality elm is now limited. Elm in bottomlands is often used along with other bottomland species for pulp and rough lumber. |
| Ornamental use | American elm was the premier ornamental tree in the world. Many cities were planted exclusively with elm as street trees. The epidemic of Dutch elm disease was a tragedy for many urban areas, but one which need not have happened had higher biodiversity been maintained in those cities. Unfortunately, we have only learned from our mistakes to the extent that we can repeat them exactly: we are still planting too few species and genotypes in nearly all cities. With the introduction of disease-resistant elms, the opportunity exists to return this species to its former status as an important ornamental. In returning this important species, we mustn't repeat the mistakes of the past by overplanting American elm. |
| Notes |
| Species | slippery elmUlmus rubra |
| Species Name | red |
| Sites and Soils | Slippery elm occurs on disturbed sites on mesic soils of lower slopes, stream banks, river bottoms; and on upland disturbed sites where spring soil moisture is adequate. It is less tolerant of inundated soils than is American elm. |
| Ecology | Slippery elm is a disturbed site species, similar in its requirements to American elm. It is intermediate in tolerance, and fast growing. Slippery elm does not tolerate inundation as well as American elm, and is not found in bottoms as frequently, nor does it occur in the Plains Extension. It is very successful as an oldfield invader, and is thus favored by the abandonment of farm land. Slippery elm is less susceptible to Dutch elm disease than is American elm, but is perhaps more susceptible to elm phloem necrosis. |
| Life History | Slippery elm flowers in very early spring, sometimes on warm days in winter. Pollination is by wind and insects (?). Seeds are dispersed by wind or water in late spring, among the earliest seeds dispersed. Germination occurs immediately on moist mineral soil, and seeds do not enter the seed bank. Growth is fairly rapid. Slippery elm usually does not live more than 200 years. |
| Interactions | VA mycorrhizal; wind and insect pollinated. Fruits are favored by songbirds. The disease complex that besets elms is further described on the Pathology page. |
| Status | Abundant; increasing with disturbance and abandonment of farm land. |
| Range | Eastern Deciduous Forest except extreme south and north. |
| Kentucky status | Common; increasing with abandonment of farm land. |
| Kentucky range | Entire state. |
| Uses | Of minor importance as a timber tree or ornamental. |
| Ornamental use | Not commonly used; form is not as good as American elm. |
| Notes |