Southeastern mixed forests

Study Area

http://www.wri.org/sites/default/files/pdf/southern_forests_for_the_future_lowres.pdf

Biome: Temperate Broadleaf and Mixed Forests
Ecoregion: Southeastern Mixed Forests
Scientific Code: NA0413
Ecozone: Neararctic
Size: 134,300 square miles
Protected Area: 3.73%
Status: Poor; Threatened and Endangered; Critical
Habitat Loss: 26.9%
Vegetation: oak-hickory-pine forests that include medium to tall broadleaf deciduous and needleleaf evergreen trees
Location/Structure: According to WWF (World Wildelife Fund), "the Southeastern Mixed Forests skirt the Appalachian/Blue Ridge Mountains, occupying the piedmont zone of the eastern United States between upland forests and the Atlantic Coastal and Gulf Coastal plains" (10). This ecoregion is considered the largest habitat within the Temperate Broadleaf and Mixed Forests biome, crossing nine states and running northeast to southwest from Maryland to Louisiana (i.e. Maryland, Virginia, North and South Carolina, Georgia, Alabama, Mississippi, Arkansas, Louisiana) (10). The Southeastern Mixed Forests are demarcated from neighboring ecoregions by vegetation and elevation (the fall line of the Atlantic Piedmont) (10). Seven sections have been delineated within this ecoregion: Southern Appalachian Piedmont, Coastal Plains – Middle, Southern Cumberland Plateau, Mid Coastal Plains – Western, Eastern Gulf Prairies and Marshes, and Arkansas Valley (1).
Climate: subtropical - hot summers and mild winters, significant precipitation throughout the year
Description of Biome: Temperate broadleaf and mixed forests are a kind of temperate deciduous forests that are found between the Polar Regions and the tropics. There are four distinct layers of vegetation: "a canopy composed of mature full-sized dominant species and a slightly lower layer of mature trees, a shrub layer, and a understory layer of grasses and other herbaceous plants"(7). Due to its structure, most of its biodiversity is close to the ground.

Blue Ridge Mountains

http://blueridgemountainhome.blogspot.com/2011/11/fall-foliage_05.html

Morrow Mountain State Park- North Carolina

http://www.meetup.com/Charlotte-Photographers/events/14229423/

Historical State

The Southeastern Mixed Forests are considered the center of gastropod (e.g. snails, slugs) diversity in North America, but many of the endemic taxa have gone extinct (10). The freshwater ecosystems (e.g. streams, marshes, lakes) found within this ecoregion are among the richest in the temperate latitudes (10). The Southeastern Mixed Forests rank among the top ten ecoregions in richness of amphibians, reptiles, and birds and among the top ten ecoregions in number of endemic reptiles, amphibians, butterflies, and mammals in the U.S. (10). There are more than 3,600 native species of herbs and shrubs, the highest in North America (10). Common shrubs and herbaceous species include blackberry (Rubus spp.), sumac (Rhus spp.), honeysuckle (Lionicera spp.), and poison ivy (Toxicodendron radicans) (Skeen et al. 1993) (10).

The natural vegetation of this ecoregion is oak-hickory-pine forests. However, it used to dominated by stands of pure pine and hardwood (10). Prior to European settlement "the most dominate ecological force in shaping the composition and structure of the Southeastern Mixed Forests was fire" (10). Fire disturbance is a natural adaptation of this ecoregion and nature provided this with lightening. Fire substantially helps maintain the stands of pines by providing good seed beds for pines to grow. In other words, fire helped ensure the reproduction of pines and oaks. Common pine species of this ecoregion included shortleaf pine (Pinus echinita), loblolly pine (Pinus taeda), and longleaf pine (Pinus palustris) (10). However, due to European settlement "hardwood species grew in after the pines and established themselves prominently in the understory" (10). American chestnut trees (Castanea dentana) were an important tree in this ecoregion, but its population was destroyed in the early 20th century by the chestnut blight (5). On a positive note, granite outcrops are among the few habitats that are in relatively good condition (10).

Shenandoah National Park- Virginia

http://www.richmondbargains.com/wp-content/uploads/2012/09/shenandoah.jpg

Buffalo National River- Arkansas

http://hawcreekoutdoors.com/Arkansas/buffalo_national_river.htm

Protected Areas

Nine blocks of habitat remain within this ecoregion "but most are in relatively poor condition, fragmented, and poorly protected" (10).

Sumter National Forest (in very poor shape) – western South Carolina
Uwharrie National Forest – central North Carolina
Bienville National Forest – east central Mississippi
Talladega National Forest (SW unit) – central Alabama
Oconee National Forest and Piedmont National Wildlife Refuge – north central Georgia
Sauratown Mountains – central North Carolina
South Mountains – south central North Carolina
Tunica Hills – southwestern Mississippi, eastern Louisiana

Talladega Forest- Alabama

http://www.toureastalabama.com/wp-content/uploads
/2011/10/talladega-forest-3.jpg

Sauratown Mountain- North Carolina

http://www.camphanes.org/wp-content/gallery/site-tour
/sauratown-mountain.jpg

Human Benefits

Beginning in the 1600s, agriculture, timber extraction, and settlements built by Europeans and their descendants gradually spread across the region, affecting the extent, distribution, and composition of southern forests. Over four centuries, more than 99% of southern forest acreage was cut or cleared to make room for development. Despite the land regenerated over time as secondary forest, the forest has declined by ~40% since the dawn of European settlement. (4)

Southern Appalachian Piedmont

Land use: Natural vegetation has been cleared for agriculture on most of the area, especially for cotton production in the 1800's. (1)

Coastal Plains, Middle

Land use: Natural vegetation has been cleared for agriculture on about 30% of the area. (1)

Southern Cumberland Plateau

Land use: Natural vegetation has been cleared for agriculture on about 30% of the area. (1)

Southern Ridge and Valley

Land use: Natural vegetation has been cleared for agriculture on over 60% of the area. (1)

Mid Coastal Plains, Western

Land use: Natural vegetation has been cleared for agriculture on about 25% of the area. Much of the non-cleared land is managed for forestry. (1)

Eastern Gulf Prairies and Marshes

Land use: Natural vegetation has been cleared for agricultural crops on about 40% of the area. (1)

Arkansas Valley

Land use: Reserved. (1)

In addition, because many vegetation in the area are deciduous, many of the protected parks serve as recreational areas, especially during autumn when the tree leaves change into beautiful arrays of color (i.e. red, orange, gold, and purple). Other benefits include: soil erosion control, air purification, water quality protection, and pulpwood for paper.

Human Impact

Human impact has dramatically altered the biological distinctiveness of Southeastern Mixed Forests. About 99 percent of this habitat has been converted to agriculture and has become highly degraded due to European settlement (10). The effects of domestication were inescapable; it led to the clearing of land and allowed open range livestock (i.e. hogs, cattle) to feed on longleaf pine seedlings (2). The one process that took decades to become effective in the South was the passing of fence laws that required farmers to fence off their land in order to prevent livestock from running off and eating all the natural forage (2). However, this is not full proof and not all farmers abided to this law. The Southeastern Mixed Forests is "the most heavily settled ecoregion along the east coast of the U.S., and much of the land has been used for growing tobacco and peanuts" (10). After World War II many farm fields were left abandoned and there was a dramatic shift in land use from plantations to croplands (2). This shift made it easier for pines to out compete hardwoods for sun and nutrients and they better able to survive in the extreme environmental conditions of the abandoned fields (10). Due to repeated harvesting of pine stands in the mid-1960s, hardwoods began to dominate the understory of Southeastern Mixed Forests (10).
Conversion to agriculture is one of the main factors that led to deforestation of this ecosystem. For example, a remnant tall grass prairie known as the Black Belt was completely converted to agriculture (10). Because of the heavy rate of conversion, there is little left to conserve. The suppression of fire and the poor management of farmlands has "altered the plant communities and threatens the long-term persistence of many fire-dependent species" (10). Furthermore, high fragmentation has led to species loss, such as the black bear. In addition, large carnivores have been largely eliminated through deliberate efforts of humans (i.e. hunting, destruction of habitats). 400 years of land use for agriculture, livestock; logging; production of turpentine, and elimination of naturally-occurring wildfires have left less than 3% of the canopy's upper layer of natural vegetation (2).

Gills Creek- South Carolina

http://www.flickr.com/photos/alan_cressler/4750721274/

Black Belt Prairie

http://mississippientomologicalmuseum.org.msstate.edu/images/prairie.photos/prairie.erosion.jpg

McTier Creek- South Carolina

http://www.flickr.com/photos/alan_cressler/4749965575/

Decreasing gymnosperms of southern mixed forests: (a) shortleaf pine, (b) longleaf pine, (c) swamp tupelo, and (d) pond cypress.
http://www.sciencedirect.com/science/article/pii/S0378112713004088

Table 1. (3)

Species (trees ≥ 12.7 cm diameter) that increased or decreased in percent composition ≥ 5% for ≥ 2 million ha between oldest and newest USDA FIA surveys in the eastern United States. The first p-values, from paired t-tests, were for all ecological subsections, weighted by area, where the species was present with > 100 stems. The second p-values, also from paired t-tests for all ecological subsections, compared small trees (<12.7 cm in diameter) in old surveys to large trees in new surveys.

Species	Scientific name	Net change ha	Change % composition	Mean year old surveys	Mean year new surveys	p-value	p-value small trees
Loblolly pine	Pinus taeda	72704702	17.6	1974	2007	<.0001	<.0001
Red maple	Acer rubrum	29479009	7.4	1984	2006	<.0001	<.0001
Eastern redcedar	Juniperus virginiana	11049718	7.8	1982	2007	<.0001	0.1533
Slash pine	Pinus elliotti	10310840	11.8	1972	2006	0.064	0.0069
Green ash	Fraxinus pennsylvanica	7789190	8.7	1980	2007	0.2169	N/A
Boxelder	Acer negundo	5609990	11.4	1982	2007	0.0743	N/A
Red pine	Pinus resinosa	5128902	8.9	1983	2006	<.0001	N/A
Black spruce	Picea mariana	3128760	8.7	1980	2006	<.0001	0.0037
Northern white-cedar	Thuja occidentalis	2603295	10.1	1984	2006	0.0363	<.0001
Sugar maple	Acer saccharum	2132676	7.0	1987	2006	0.0011	0.1717
Tamarack	Larix laricina	2092218	10.3	1980	2006	0.0037	0.1632
Jack pine	Pinus banksiana	−2066916	−8.3	1979	2006	0.009	0.3393
Paper birch	Betula papyrifera	−2594284	−7.0	1982	2006	<.0001	0.1072
Eastern white pine	Pinus strobus	−3040918	−7.4	1986	2006	0.3578	0.3924
Virginia pine	Pinus virginiana	−5335089	−7.0	1979	2006	0.0004	0.4223
Pond pine	Pinus serotina	−5571550	−5.7	1972	2006	0.0005	N/A
Pond cypress	Taxodium ascendens	−5824112	−9.2	1970	2005	0.0015	N/A
American basswood	Tilia americana	−6116642	−7.0	1983	2006	0.0066	0.7936
Longleaf pine	Pinus palustris	−9881192	−8.0	1972	2007	<.0001	0.2804
Quaking aspen	Populus tremuloides	−12491657	−10.1	1979	2006	<.0001	<.0001
Black oak	Quercus velutina	−12661395	−8.3	1984	2007	<.0001	0.0002
Northern red oak	Quercus rubra	−14178855	−9.3	1984	2006	<.0001	0.0843
Swamp tupelo	Nyssa biflora	−14404729	−6.8	1972	2006	<.0001	0.0561
White oak	Quercus alba	−23820115	−7.6	1982	2006	<.0001	0.0325
Shortleaf pine	Pinus echinata	−38282915	−12.1	1975	2007	<.0001	0.1218

Table 2. (3)
Percent composition (trees ≥ 12.7 cm diameter) of eastern forests by pines, other gymnosperms, oaks, other angiosperms, and most frequent species for oldest (mean year = 1981) and newest (mean year = 2006) USDA FIA tree surveys, as well as the percent composition of groups for smaller trees (<12.7 cm diameter) in newest surveys. The first p-values, from paired t-tests, were for all ecological subsections, weighted by area, where the group contained ≥100 stems. See Table 1 for scientific names of increasing and decreasing species.

Forest type	Group	Old surveys		New surveys			p-value
Forest type	Group	%	Most frequent	%	Most frequent	% Small trees	p-value
Eastern broadleaf	Pines	7.4	Eastern white pine	8.0	Eastern white pine	4.3	0.0233
Eastern broadleaf	Other gymnosperms	3.1	Eastern hemlock, Tsuga canadensis	5.6	Eastern redcedar	5.5	<.0001
Eastern broadleaf	Oaks	38.2	White oak	26.6	White oak	9.5	<.0001
Eastern broadleaf	Other angiosperms	51.4	Red maple	59.8	Red maple	80.7	<.0001
Southeastern mixed	Pines	40.9	Loblolly pine	47.9	Loblolly pine	20.5	<.0001
Southeastern mixed	Other gymnosperms	3.6	Pond cypress	2.8	Pond cypress	2.3	0.0085
Southeastern mixed	Oaks	20.7	White oak	15.0	Water oak,Quercus nigra	16.1	<.0001
Southeastern mixed	Other angiosperms	34.8	Sweetgum, Liquidambar styraciflua	34.3	Sweetgum	61.1	0.0005
Northern mixed	Pines	7.7	Jack pine	8.9	Red pine	2.7	0.2194
Northern mixed	Other gymnosperms	25.9	Northern white-cedar	30.5	Northern white-cedar	37.2	<.0001
Northern mixed	Oaks	6.1	Northern red oak	4.8	Northern red oak	1.8	<.0001
Northern mixed	Other angiosperms	60.3	Quaking aspen	55.8	Red maple	58.3	<.0001
Prairies/savannas	Pines	1.9	Loblolly pine	3.0	Loblolly pine	2.3	0.0706
Prairies/savannas	Other gymnosperms	0.9	Eastern redcedar	4.4	Eastern redcedar	5.5	N/A
Prairies/savannas	Oaks	36.4	White oak	26.4	Post oak,Quercus stellata	13.8	<.0001
Prairies/savannas	Other angiosperms	60.8	American elm, Ulmus americana	66.2	American elm	78.5	<.0001
Prairies	Pines	4.0	Ponderosa pine, Pinus ponderosa	3.7	Ponderosa pine	2.0	N/A
Prairies	Other gymnosperms	3.2	Eastern redcedar	22.7	eastern redcedar	43.0	N/A
Prairies	Oaks	8.4	Bur oak, Quercus macrocarpa	11.5	Bur oak	4.1	N/A
Prairies	Other angiosperms	84.4	Eastern cottonwood,Populus deltoides	62.0	Green ash	50.9	0.4571