Sumter National Forest Final Report - NatureServe

RIVER BIRCH - SYCAMORE / SMOOTH ALDER / FALSE NETTLE FORESTELEMENT IDENTIFIERSNVC association: Betula nigra - Platanus occidentalis / Alnus serrulata / Boehmeria cylindrica ForestDatabase Code: CEGL007312Formation: Temporarily flooded cold-deciduous forest (I.B.2.N.d)Alliance: Betula nigra - (Platanus occidentalis) Temporarily Flooded Forest Alliance (A.280)ELEMENT CONCEPTSummary: This riverfront forest, dominated by Betula nigra and Platanus occidentalis, occurs primarily on levees along small riversand streams. It also is found along flowages of larger rivers ('artificial oxbows'). It ranges from Virginia to southern Georgia in thePiedmont and Coastal Plain (and into the southern and lower-elevation parts of the Southern Blue Ridge, excluding the highestelevations of the Mountains) and west to eastern Texas, and possibly the Cumberland Plateau of northern Alabama. No effort hasbeen made to subdivide this type into northern and southern, or Coastal Plain and Interior variants, although there are undoubtedlysome floristic differences between these extremes, at least in the lower strata.Platanus occidentalis may be codominant, or at least prominent, with large individuals overtopping the Betula, which tends to have agreater number of stems, but Platanus occidentalis may be more conspicuous because of its larger size. Other canopy associatesinclude Liriodendron tulipifera, Liquidambar styraciflua, Acer rubrum, Acer negundo, Ulmus americana, Ulmus rubra, Celtis spp.,and Quercus spp. The subcanopy or tall-shrub strata may include Cornus florida and Carpinus caroliniana, along with Acer rubrum,Ilex opaca, Ulmus alata, Prunus serotina, and Carya spp. Shrubs and woody vines may include Alnus serrulata, Euonymusamericana, Parthenocissus quinquefolia, Smilax rotundifolia, Toxicodendron radicans, and Vitis rotundifolia. Herbs may includeBoehmeria cylindrica, Polygonum virginianum, Rudbeckia laciniata, Sanicula sp., Symphyotrichum lateriflorum (= Asterlateriflorus), Thalictrum dioicum, Viola sororia, Polystichum acrostichoides, Woodwardia areolata, Botrychium dissectum,Botrychium virginianum, and Impatiens capensis. The exotics Ligustrum sinense, Lonicera japonica, Microstegium vimineum, andRosa multiflora may spread into disturbed examples of this community.Environment: Betula nigra requires soils near field capacity throughout the year but is relatively intolerant of flooding; Platanusoccidentalis also is intolerant of flooding during the growing season and will die if the entire tree is inundated for more than twoweeks. The absence of this community in the lower Mississippi River Alluvial Plain is attributed this intolerance, as is its mostcommon location on levees of smaller rivers. The community usually is found on the natural levee of the watercourse and, therefore,is slightly elevated from the flats behind the levee. The community is more common along small streams and blackwater streams thanalong alluvial floodplains, mostly because of the higher sustained flow rates of these larger rivers. It also is found along flowages oflarger rivers ("artificial oxbows") in southeast Kentucky. In the Upper East Gulf Coastal Plain (Shiloh National Military Park, HardinCounty, Tennessee), this association occurs along small stream floodplains.Vegetation: Betula nigra contributes at least 50%, and often more, of the tree density of stands of this community. Platanusoccidentalis may be codominant, or at least prominent, with large individuals overtopping the Betula, which tends to have a greaternumber of stems, but Platanus occidentalis may be more conspicuous because of its larger size. Other canopy associates includeLiriodendron tulipifera, Liquidambar styraciflua, Acer rubrum, Acer negundo, Ulmus americana, Ulmus rubra, Celtis spp., andQuercus spp. Pinus echinata, Pinus strobus, or Pinus virginiana may be found in some montane or submontane examples. Thesubcanopy or tall-shrub strata may include Cornus florida and Carpinus caroliniana, along with Acer rubrum, Ilex opaca, Ulmusalata, Prunus serotina, and Carya spp. Shrubs and woody vines may include Alnus serrulata, Euonymus americana, Parthenocissusquinquefolia, Smilax rotundifolia, Toxicodendron radicans, and Vitis rotundifolia. Herbs may include Boehmeria cylindrica,Polygonum virginianum, Rudbeckia laciniata, Sanicula sp., Symphyotrichum lateriflorum (= Aster lateriflorus), Thalictrum dioicum,Viola sororia, Polystichum acrostichoides, Woodwardia areolata, Botrychium dissectum, Botrychium virginianum, and Impatienscapensis. The exotics Ligustrum sinense, Lonicera japonica, Microstegium vimineum, and Rosa multiflora may spread into disturbedexamples of this community. No effort has been made to subdivide this type into northern and southern, or Coastal Plain and Interiorvariants, although there are undoubtedly some floristic differences between these extremes, at least in the lower strata.Dynamics: Forests in this alliance occur on riverfronts in areas with repeated, frequent, natural disturbance in the form of flooding.Occurrences of this type may have a rather high percentage of standing dead trees, including remnant snags from earlier successionalcommunities. A layer of sand is often deposited at the surface of the soil when streams overflow their banks during flash floods. Littleor no clay is present in the upper strata of soils which support stands of this alliance. Flooding is seasonal and/or occasional andshallow, but never prolonged. Most of this short-duration flooding takes place in early spring.This is a Zone IV community. Zone IV communities experience seasonal inundation or groundwater saturation for approximately12.5-25% of the year, usually during spring and early summer with a frequency of 51-100%.This community often succeeds riverfront forests dominated by Salix spp. and Populus spp. It probably succeeds to forests dominatedby Celtis spp., Ulmus spp., Fraxinus pennsylvanica, and Liquidambar styraciflua.Similar Associations:Vegetation of Sumter National Forest April 30 2004Copyright © 2004 NatureServe90