BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ulmus rubra | Slippery Elm 



GENERAL BOTANICAL CHARACTERISTICS : 
Slippery elm is a native, medium-sized, deciduous tree reaching 60 to 70
feet (18-21 m) on average sites and 135 feet (41 m) on the best sites.
In the forest, it has a straight bole with the trunk dividing into
widespreading limbs high up the tree.  The crown is broad and rather
flat topped.  The perfect flowers form dense packed clusters.  The root
system is shallow but widespreading [8,11,18,21].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Seeds of slippery elm are larger than those of many of the native elms.
Dispersal is by gravity and wind [10,16].

Seeds sometimes show dormancy; seedlings are susceptible to damping off.
Seedlings become established under a wide variety of conditions.
Mineral soil seedbeds are best, but seeds germinate and survive in
forest litter or among herbaceous plants [6,10].

Slippery elm sprouts readily from the stump or root crown.  Seedlings
produces sprouts from rhizomes.  Slippery elm also reproduces by
layering.  Rootstocks of slippery elm are grafted to hybrid elms [10].


SITE CHARACTERISTICS : 
Slippery elm grows best on moist, rich soils of lower slopes,
streambanks, river terraces, and bottomlands but is also found on much
drier sites, particularly those of limestone origin.  Examples of sites
on which it is an important species are floodplains, terraces, and
well-drained uplands in east-central Illinois; the northern Mississippi
River floodplain; alluvial terraces in western Pennsylvania; lower
ravine slopes and uplands in central New York.  Slippery elm can persist
on poorly drained soils that are occasionally flooded for periods of 2
or 3 months, but it does not reproduce or grow well if flooding is
frequent or prolonged [2,10,14,25,34].

In addition to those species in SAF cover types, common associates of
slippery elm include hickory (Carya spp.), box elder (Acer negundo),
blackgum (Nyssa sylvatica), black walnut (Juglans nigra), hackberry
(Celtis occidentalis), and honeylocust (Gleditsia triacanthos) [5,9,22].


SUCCESSIONAL STATUS : 
Facultative Seral Species.

Slippery elm is one of the more shade-tolerant species [4].  It is much
more tolerant than quaking aspen (Populus tremuloides) but slightly less
tolerant than sugar maple (Acer saccharum).  Reproduction is erratic
under fully stocked stands.  In a river terrace forest in east-central
Illinois, slippery elm was present in most size classes, but no
seedlings were present.  A nearby upland coppice, however, contained
numerous slippery elm seedlings.  Slippery elm is frequently a component
of the subcanopy [10,20,29].


SEASONAL DEVELOPMENT : 
The flowers open before the leaves, from February to May, depending on
weather and location.  Seeds ripen from April to June and are dispersed
by wind and water as soon as they are ripe [10].

Related categories for Species: Ulmus rubra | Slippery Elm