KUCHLER TYPE DESCRIPTION
Kuchler Type: Northern floodplain forest


PHYSIOGRAPHY : 
Where the upper Missouri River flows through South Dakota, western Iowa,
eastern Nebraska and adjoining areas of Missouri and Kansas, the topography
is mostly rolling to hilly; elevations in this area range from 1,250
feet (381 m) at the Nebraska-South Dakota line to 850 feet (259 m) in
southeastern Nebraska [51].  In southern Illinois, bottomlands are
characteristically flat; slight variations in elevation are associated
with different soils, drainage conditions, and trees species.
Characteristic features include ridges, flats, sloughs, swamps,
sandbars, pointbars, and natural levees [23].

On the Wabash River, Indiana, upper terraces have mostly been cleared
for cultivation; first bottoms are still forested [33].  First bottoms
are subject to frequent flooding.  Second bottoms and upper terraces
formed by older drainage systems rarely experience floods [23].


CLIMATE : 
The elm-ash-cottonwood ecosystem, which includes northern floodplain
forests, crosses several climatic zones.  It is characteristic of moist
sites that either flood frequently, receive abundant precipitation, or
both.  Mean annual precipitation ranges from approximately 10 inches
(254 mm) near the Rocky Mountain foothills to 50 inches (1,270 mm) in
southern and northeastern areas [15].

Central North Dakota:  This climate is described as dry subhumid
mesothermal.  Precipitation is substantially lower than potential
evapotranspiration.  The average frost-free period is 140 days.  The
mean annual precipitation is 16.5 inches (420 mm), 70 percent of which
falls in growing season, 50 percent from May to July [24].  Severe
drought occurs about once every 10 years at the North Dakota-Minnesota
border, and about once every 20 years in Minnesota.  The Red River Basin
has a mean annual temperature ranging from 36 to 43 degrees Fahrenheit
(2.2-6 deg C) on a north-south gradient.  Average annual precipitation
ranges from a low of 16 inches (406 mm) in the west to a high of 25
inches (635 mm) in the east [49].

Western Iowa to eastern Nebraska:  Mean annual precipitation is 34
inches (864 mm) in western Iowa [51].  Eastern Nebraska has a
continental climate with average annual precipitation of 23 inches (584
mm).  The mean annual temperature is 51.6 degrees Fahrenheit (10.9 deg
C).  The average number of frost-free days is 188.  Eastern Nebraska
experiences occasional drought years with annual precipitation below 19
inches (480 mm) [43,51].

Southern Illinois:  The climate is continental with hot summers and cool
to cold winters.  Average frost-free periods range from 180 to 210 days.
The mean annual precipitation ranges from 42 to 47.9 inches (1,066-1,216
mm).  May is the wettest month, July the driest.  Extended periods of
soil moisture deficit are common in mid- to late summer [23].


SOILS : 
Floodplain soils are silts, sands, and clays; soil development is
largely driven by fluvial processes.  The soils under young stands of
cottonwoods and willows tend to be sandy with limited amounts of organic
matter and are low in nutrients and available water capacity.  Available
water capacity is higher in soils under older stands which have
developed higher organic matter content and have higher nutrient levels
due to flood-deposited silts.  Changes in the surface soil texture can
occur rapidly in floodplain communities due to flood-carried siltation
[24].  Soil types and development in the Red River Valley of North
Dakota are discussed in detail by Wanek [49].

Wilson [53] described eastern cottonwood (Populus deltoides var.
deltoides) forests along the Missouri River in southeastern South
Dakota.  Over 20 years of eastern cottonwood growth, there was a gradual
change from the initial dry sandy surface soils supporting little
undergrowth to moist clay or silt surface soils with an abundance of
shrubs.


VEGETATION : 
Kuchler [30] lists three dominant tree species for northern floodplain
forest:  eastern cottonwood, black willow (Salix nigra), and American
elm (Ulmus americana).  Cottonwoods (Populus spp.) often occur in pure
or nearly pure stands [15].

Other components of northern floodplain forest include (in alphabetical
order by scientific name) boxelder (Acer negundo), red maple (A.
rubrum), silver maple (A. saccharinum), river birch (Betula nigra),
American bittersweet (Celastrus scandens), hackberry (Celtis
occidentalis), virgin's bower (Clematis virginiana), white ash (Fraxinus
americana), green ash (F. pennsylvanica), honeylocust (Gleditsia
triacanthos), black walnut (Juglans nigra), Virginia creeper
(Parthenocissus quinquefolia), sycamore (Platanus occidentalis) in the
south, plains cottonwood (Populus deltoides var. occidentalis) in the
west, eastern poison-ivy (Toxicodendron radicans), peachleaf willow
(Salix amygdaloides), sandbar willow (S. exigua), bristly greenbrier
(Smilax hispida), coralberry (Symphoricarpos orbiculatus), and slippery
elm (U. rubra) [30].  Garrison and others [15] list sugarberry (Celtis
laevigata) for southern stands.  Streamside stands of trees in North
Dakota include bur oak (Quercus macrocarpa), American basswood (Tilia
americana), green ash, American elm, boxelder, quaking aspen (P.
tremuloides), and paper birch (Betula papyrifera).  These stands appear
to be successionally related to northern floodplain forest as defined by
Kuchler [52].

The following Society of American Foresters cover types appear to
overlap with Kuchler's definition of northern floodplain forest:
cottonwood (SAF 63), black willow (SAF 95), cottonwood-willow, and
silver maple-American elm (SAF 235) [14].  The cottonwood type (which
includes eastern cottonwood, plains cottonwood, and swamp cottonwood [P.
heterophylla]) is a pioneer type.  Cottonwoods occur with or precede
willows, usually sandbar willow, black willow, or peachleaf willow.  In
some areas the willow stage is identifiable as a separate cover type
(black willow).  Early successional associates in the cottonwood type
include white ash, green ash, silver maple, and American elm in the
north, and pecan (Carya illinoensis), sycamore, and sugarberry in the
south.  Cottonwoods are somewhat less flood tolerant than willows; with
frequent and/or extended flooding willows may survive cottonwoods and
dominate the site.  Cottonwood merges with cottonwood-willow (SAF 235)
in the eastern Great Plains [14].

Cottonwood-willow (SAF 235) occurs mostly as gallery forest in
grasslands.  It is a climatic anomaly because it includes species that
occur regularly in cooler areas with abundant precipitation.  It
therefore is considered a specialized type whose existence depends on
groundwater availability.  This type includes other species of
cottonwood in addition to eastern cottonwood and plains cottonwood:
lanceleaf (P. xacuminata), Fremont (P. fremontii), Rio Grande (P.
fremontii var. wislizeni), narrowleaf (P. angustifolia), and black
cottonwood (P. trichocarpa).  Willows are secondary only to cottonwood
and usually include black willow, peachleaf willow, other tree willows,
and many shrubby willow species.  Minor associates include boxelder and
hackberry; other species described for this type occur farther south and
west than northern floodplain forest [14].

Species that commonly invade cottonwood-willow stands in northern
floodplain forests include sycamore, sweet pecan, hackberry, sugarberry,
river birch, green ash, American elm, silver maple, red maple, and
boxelder.  The silver maple-American elm cover type (SAF 62) is most
common in the Ohio, Wabash, upper Mississippi, and Missouri river
valleys and also occurs in the Great Lakes and St. Laurence River
regions of Canada.  It is usually a subclimax type following cottonwoods
and willows; it is a climax type in southern Ontario.

Other community descriptions and classification systems that contain
types approximately equivalent to northern floodplain forest include the
following:

A preliminary classification of the natural vegetation of Colorado [2]
Composition and environment of floodplain forests of northern Missouri [11]
Native woodland habitat types of southwestern North Dakota [17]
Riparian dominance types of Montana [20]
Floristic analysis of the Missouri River bottomland forest in North
  Dakota [26]
A comparison of the plant communities of the South Platte and Arkansas
  River drainages in eastern Colorado [32]
Vegetation and environment along the Wabash and Tippecanoe Rivers [33]
Community analysis of the forest vegetation in the lower Platte River
  Valley, eastern Nebraska [43]
The timber resources of North Dakota [50]


WILDLIFE : 
Birds:  Birds are the most common and conspicuous form of wildlife in
riparian ecosystems, and much research describes riparian bird
communities.  The most abundant breeding birds on 998 census plots in
riparian vegetation (all areas) included red-eyed vireo (Vireo
olivaceus), northern cardinal (Cardinalis cardinalis), common
yellowthroat (Geothlypis trichas), song sparrow (Melospiza melodia),
wood thrush (Hylocichla mustelina), American redstart (Setophaga
ruticilla), Acadian flycatcher (Empidonax alnorum), red-winged blackbird
(Agelaius phoeniceus), European starling (Sturnus vulgaris), American
robin (Turdus migratorius), gray catbird (Dumetella carolinensis),
tufted titmouse (Parus bicolor), house wren (Troglodytes aedon),
mourning dove (Zenaida macroura), eastern wood pewee (Contopus virens),
yellow warbler (Dendroica petechia), rufous-sided towhee (Pipilo
erythrophthalmus), northern oriole (Icterus galbula), indigo bunting
(Passerina cyanea), ovenbird (Seiutus aurocapillus), northern parula
(Parula americana), northern flicker (Colaptes auratus), and blue jay
(Cyanocitta cristata) [8].  Kricher's [29] list of indicator animals for
northern floodplain forests includes belted kingfisher (Ceryle alcyon),
bank swallow (Riparia riparia), spotted sandpiper (Actitus macularia),
green-backed heron (Butorides striatus), wood duck (Aix sponsa),
yellow-throated vireo (V. flavifrons), and blue-gray gnatcatcher
(Polioptila caerulea).

The most abundant lowland forest (assumed to be equivalent to northern
floodplain forest) bird species on the Platte River, Nebraska, include
house wren, mourning dove, American robin, and brown-headed cowbird
(Molothrus ater).  The eastern phoebe (Sayornis phoebe), eastern wood
pewee, Bewick's wren (Thryomanes bewickii), eastern bluebird (Sialia
sialis), blue grosbeak (Guiraca caerulea), lazuli bunting (Passerina
amoena), and rufous-sided towhee occurred in the area only in this
habitat type.  The most numerous species occurring on wooded sandbars
were cliff swallow (Hirundo pyrrhonota) and common yellowthroat.  Other
species on wooded sandbars included belted kingfisher, willow flycatcher
(E. traillii), bank swallow, Bell's vireo (Vireo bellii), northern
cardinal, and indigo bunting [48].  Garrison and others [15] add the
following typical forest edge birds as common in elm-ash-cottonwood
ecosystems:  northern bobwhite (Colinus virginianus), American goldfinch
(Carduelis tristis), yellow-billed cuckoo (Coccyzus americanus), lark
sparrow (Chondestes grammacus), northern mockingbird (Mimus
polyglottos), common crow (Corvus brachyrhynchos), ruby-throated
hummingbird (Archilochus colubris), and Cooper's hawk (Accipiter
cooperii).

Mammals:  Mammals commonly occurring in riparian areas in the northern
Great Plains include eastern mole (Scalopus aquaticus), shrews (Family
Soricidae), raccoon (Procyon lotor), mink (Mustela vison), striped skunk
(Mephitis mephitis), spotted skunks (Spilogale spp.), red fox (Vulpes
vulpes), coyote (Canis latrans), fox squirrels (Sciurus spp.), pocket
gophers (Thomomys spp.), ground squirrels (Spermophilus spp.), beaver
(Castor canadensis), western harvest mouse (Reithrodontomys megalotis),
deer mouse (Peromyscus maniculatus), white-footed mouse (Peromyscus
leucopus), hispid cotton rat (Sigmodon hispidus), northern red-backed
vole (Clethrionomys rutilus), common muskrat (Ondatra zibethicus),
meadow jumping mouse (Zapus hudsonius), cottontails (Silvilagus spp.),
swamp rabbit (S> aquaticus), jackrabbits and hares (Lepus spp.),
white-tailed deer (Odocoileus virginiana), and mule deer (O. hemionus)
[8,15].

Reptiles and Amphibians:  Common reptiles and amphibians in Plains
grasslands riparian ecosystems include snapping turtle (Chelydra
serpentina), mud turtles (Kinosternon spp.), sliders (Trachemys spp.),
cooters (Pseudemys spp.), water turtles (Clemmys spp.), box turtles
(Terrapene spp.), softshell turtles (Apalone spp.), earless lizards
(Holbrookia spp.), spiny lizards (Sceloporus spp.), skinks (Scincella
and Eumeces spp.), whiptails and racerunners (Cnemidophorus spp.), water
snakes (Nerodia spp.), redbelly and brown snakes (Storeria spp.), racers
(Coluber spp.), green snakes (Opheodrys spp.), rat snakes (Elaphe spp.),
bullsnake (Pituophis melanoleucus sayi), eastern massassauga (Sistrurus
catenatus catenatus), pygmy rattlesnakes (Sistrurus spp.), rattlesnakes
(Crotalus spp.), mole salamanders (Ambystoma spp.), spadefoots
(Scaphiopus spp.), toads (Bufo spp.), cricket frogs (Acris spp.),
treefrogs (Hyla spp.), and true frogs (Rana spp.) [8].


ECOLOGICAL RELATIONSHIPS : 
Northern floodplain forest dynamics are controlled by fluvial processes
and moisture availability.  Hydroperiod determines vegetation survival
and nutrition.  The hydroperiod may be coincidental with nutrient pulses
(i.e., silt deposition), but nutrient availability is dependent on
acidity and oxygenation; these are determined in large part by soil water
capacity [13].

The northern floodplain forests within the Great Plains (usually
described as gallery forests) are limited in extent by moisture
availability and by fire.  These forests are usually confined by
moisture requirements to moist, sheltered sites on the bottoms and lower
slopes of draws [7,51]. It is generally accepted that prior to 1855,
woody vegetation in the Great Plains existed almost exclusively along or
near rivers and streams [44].  During presettlement times frequent
prairie fires commonly burned up to and sometimes on to the slope
bordering the river valleys where northern floodplain forests developed
[21,42,43].

In northern floodplain forests, willows are usually the species closest
to water's edge, followed by cottonwoods, elms, boxelder, and ashes.
When a stream develops a floodplain with wide, protecting banks,
large-fruited species such as bur oak, black walnut, hickory (Carya
spp.), and hazel (Corylus spp.) are able to establish and survive
[49,51].  Boggs [6] identified the following community types for
riparian areas along the lower Yellowstone River in Montana:  bare
sandbar, willow thicket, cottonwood forest, green ash forest, and
grassland.

Northern floodplain forests originate with stream channel movement and
after floods.  The light, windblown seeds of cottonwoods and willows
require bare, moist mineral soil for seedling establishment
[12,14,15,51].  Cottonwoods and willows are common pioneers on point
bars, well-drained flats, front land ridges, and newly formed natural
levees [12,14,15].  New stream development is often accompanied by
cottonwood and willow establishment [51].  Distinct zones of
establishment often separate cottonwood and sandbar willow, with sandbar
willow on the more frequently flooded sites [38].

Willows, particularly sandbar willow, have abundant fibrous roots which
help stabilize soils.  Their roots and stems also help catch silts and
clays carried by floodwaters, further adding to soil development.
Cottonwoods exhibit very rapid growth and usually overtop willows,
except at the water's edge where the more flood-tolerant willows outlive
cottonwoods.  Occasionally erosion is rapid enough to remove the
willow-dominated zone to the point where cottonwood stands are in
contact with the river's edge [51].

On the Little Missouri River in western North Dakota, cottonwoods occur
in a series of even-aged stands corresponding to channel migration
events [12].  River meandering and lateral movement of the channel,
deposition on interior curves, collapse of cut banks, and floods ensure
a constant supply of bare sites for cottonwood and willow establishment
and initiation of succession [12,24].  Cottonwood seedlings are often
"flood trained":  Young stems are bent over by floodwaters with the
direction of flow.  These stems are often silted into position and
subsequently sprout, forming small groves of trees from one original
seedling [12].  Young cottonwood-willow forests in central North Dakota
are composed of many small trees from 18 to 36 feet (6-12 m) tall [24].
During floods, stems over 8 inches (20.3 cm) in diameter may break or
become uprooted rather than bend over [12].

In western North Dakota, the herb layer of young cottonwood forests is
mostly composed of annuals including clovers (Trifolium spp.).  Gradual
establishment of shrubs and vines such as elderberry (Sambucus
canadensis), coralberry, American bittersweet, and grapes (Vitis spp.)
is facilitated by frugivorous birds [51].

Old cottonwood stands in central North Dakota consist of trees from 59
to 80 feet (18-24 m) tall that are widely spaced with large, straight,
unbranched boles ranging from 6 to 36 inches (16-91 cm) dbh.  There is
rarely a closed canopy; the open stand allows numerous species of shrubs
and saplings of other species to develop a distinct layer.  Arboreal
lianas are prominent [24].  Older forests contain more perennial grasses
and shrubs than do young stands.  Very few cottonwood saplings and
seedlings are found under cottonwood canopies.  Old trees occasionally
regenerate by suckering [12].  In southeastern South Dakota, cottonwood
reproduction of any kind is rare after 15 to 25 years of cottonwood
overstory growth [53].

The cottonwood-willow stage is followed by river birch and silver
maple-American elm types in the north, and sycamore-pecan-American elm
or sugarberry-American elm-green ash types in southern Illinois,
Indiana, and Kentucky [14,15].  In western North Dakota, replacement of
cottonwood trees occurs from about 30 to 60 years.  Common replacement
species include green ash, Rocky Mountain juniper (Juniperus
scopulorum), American elm, and boxelder.  Old stands usually retain a
few old cottonwoods [12].  In central and southeastern North Dakota,
green ash, boxelder, American elm, and bur oak usually replace
cottonwoods and are predominant in old stands near the edge of the
floodplain [24].  In central North Dakota floodplains, tree species
diversity increases with stand age in the initial stages of replacement,
is maximal in stands with mixtures of intolerant and tolerant species,
and decreases slightly in the oldest stands [24].

Mature cottonwood forests adjacent to grasslands may be replaced by
shrubs and eventually, grasses, depending on moisture availability [6].

Related categories for Kuchler Type: Northern floodplain forest