Quercus oglethorpensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Fagales Fagaceae

Scientific Name: Quercus oglethorpensis W.H.Duncan
Common Name(s):
English Oglethorpe Oak
Taxonomic Source(s): Trehane, P. 2007-2018. The Oak Names Checklist. Available at: (Accessed: 2 February 2016).
Taxonomic Notes: This species was previously thought of as Q. imbricaria (Shingle Oak), but further investigation by Duncan showed them to represent an unnamed species that he described as Q. oglethorpensis.
Identification information: NOTES: - Correct dist info
- No sites found by Jordan Wood
- make citation for Lobdell and Thompson 2016 (ex-situ article)

Assessment Information [top]

Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2017
Date Assessed: 2016-11-28
Assessor(s): Beckman, E.
Reviewer(s): Oldfield, S.
Contributor(s): Wood, J. & Lobdell, M.

Oglethorpe Oak (Quercus oglethorpensis) has a patchy distribution in southern US, with an estimated area of occupancy (AOO) between 500 and 2,000 km2, and the potential of severe fragmentation, if more data is gathered regarding population size and density. Many ongoing and potential threats, as well as evidence of little recruitment, point to a continuing trend of population decline, even if levels of destruction have reduced since mid-20th century. These qualifications would place the species within the Vulnerable category of criterion B2.

Looking at the current knowledge of population size, the number of mature individuals remaining can be estimated at 1,000 with less than 250 mature individuals in each subpopulation. These values fall within the requirements for Endangered C2a(i). Since this is the higher of the two possible threat levels, the species is assessed as Endangered due to a small population size consisting of small, isolated subpopulations.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Quercus oglethorpensis has a disjointed distribution across its range, with smaller clusters of localities in northeast Louisiana, southeast Mississippi, and southwest Alabama, and a more extensive and well-known distribution from northeast Georgia across the border into South Carolina. There has been relatively little research regarding the full distribution of this species, as it was described fairly late (1940) and has only recently received attention from the botanic community. From 1975 to 2013, about seven new localities were discovered. It is known to be locally uncommon, and previous sites have recently been found unoccupied upon the following visit (Lobdell and Thompson 2016).

Overall less than 150 localities have been identified, with spatial data currently available for about 50 of these localities (Coder 2003). Of these 50 sites, approximately 30 have been recorded or confirmed since 2005, and 15 since 2015 (NatureServe 1996, M. Lobdell pers. comm. 2015, J. Wood pers. comm. 2016). Using all available spatial data, Q. oglethorpensis has a calculated extent of occurrence (EOO) of about 130,000 km2, and approximately 80,000 kmwhen only using data since 2005 (GeoCAT 2016). The area of occupancy (AOO) is more tricky for this species, since there has not been extensive documentation of available habitat or all current individuals; using the 50 know points alone, the AOO is 180 km2. This is surely an underestimation. Adding a 5 kmbuffer around each of these points yields an area of about 3,000 km2. Depending on how many trees are undocumented, and how widely they are spread, this may be a more accurate estimate.
Countries occurrence:
United States (Alabama, Georgia, Louisiana, Mississippi, South Carolina)
Additional data:
Estimated area of occupancy (AOO) - km2:180-3000Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:130000
Continuing decline in extent of occurrence (EOO):Unknown
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Though there is still data to be gathered, Q. oglethorpensis has received some recent attention after many years of little research; the US Forest Service and American Public Gardens Association jointly supported an ex-situ conservation effort in Spring 2015 to collect wild seeds and/or samples of scion wood for propagation, to be distributed among Nationally Accredited Collections. Sites across the species' range were visited during this collecting trip, lead by Matt Lobdell and Patrick Thompson. In 2016, Jordan Wood visited nine sites to collect material for testing of neutral genetic markers in an effort to inform conservation protocols. Subpopulations visited during these last two trips include the following, listed from east to west across the species' range:
  • York County, South Carolina: After a valiant effort, Matt Lobdell and Ethan Kauffman could not locate this historic subpopulation and believe it may be extirpated.  
  • Sumter National Forest, McCormick and Edgefield Counties, South Carolina: In this area, Q. oglethorpensis is noted to be both healthy and more "locally common" than the subpopulations visited in Mississippi or Alabama. But, once again, of the "4 known locations visited, only one observed with good fruit production" (Lobdell and Thompson 2016). Jordan Wood observed 2 sites, with about 8 and 30 individuals, respectively.
  • Buffalo Creek and Goosepond Creek, Oglethorpe County, Georgia: Wood found about 50 individuals in the first site which is the original area of discovery. Twenty-five individuals were observed in the second subpopulation, some of which spread onto private land.
  • Watson Mill Bridge State Park, Madison County, Georgia: This site was visited by J. Wood, but no specific population information was collected.
  • Oconee National Forest, Jasper and Baldwin County, Georgia: With the leadership of John Jensen and Tom Patrick from Georgia Department of Natural Resources, Lobdell and Thompson located the "large population of Q. oglethorpensis and Q. shumardii" present within the park. Upon visiting the same area, Jordan Wood observed 100 individuals (mature and immature) with another 400 found to the north, east, and west. He does note that 75% of these individuals are seedlings. 
  • Marengo and Wilcox Counties, Alabama: This subpopulation, resting right on the border of two counties, was found to be robust; at least 60 individuals were identified and fruit production seemed sufficient, but "seedling recruitment was virtually non-existant" (Lobdell and Thompson 2016). A few new occurrences were also discovered along the road, about 3 km north of the known site, but are vulnerable due to their location.
  • Sumter County, Alabama: Lobdell and Thompson found this historically known subpopulation to be extirpated due to land clearing or logging activities. 
  • Bienville National Forest, Scott County, Mississippi: Three sites were located by Lobdell and Thompson, which looked to be in good health and security save some competition from other species. But, no fruit production was observed and propagation by grafting is currently underway at The Morton Arboretum. Jordan Wood observed approximately 35 individuals.
  • Copenhagen Hills Preserve and separate private property, Caldwell County, Louisiana: About 200 individuals were observed by J. Wood in each of these two nearby subpopulations.
All of these reported "individuals" (this term refers to both mature and immature specimens unless otherwise noted) from 2015 and 2016 together equal approximately 1,200. If this number is used as an estimation of mature individuals, it is surely an over-estimation, since the locality with 500 individuals was noted to be comprised of about 75% seedlings. Assuming all other sites include almost entirely mature individuals, this would leave the count at less than 1,000. This is still a very generous estimation when including only recently visited sites, but perhaps this value can serve as an approximate place-holder representing the sites not accounted for, until more exploration is carried out.

Current Q. oglethorpensis sites (some visited within the last two years, some passed over) are also referenced by Coder in his 2003 article "Oglethorpe Oak: Sunset of a Species." These include "approximately 70 sites in Georgia found in Elbert, Greene, Jasper, Oglethorpe, and Wilkes counties... about 70 sites in South Carolina found in Abbeville, Edgefield, Greenwood, McCormick, and Saluda counties... three sites are found in Mississippi in Scott, Smith, and Jasper counties all on the Bienville National Forest (less than 100 stems total – all less than eight inches in diameter)... single site is found in Louisiana’s Caldwell parish." He also acknowledges the high probability of further specimens still existing unknown in the wild areas of the Southeast. About 90% of the original Oglethorpe Oak sites are though to remain, while the number of individuals continues to slowly decline. Coder believes that the number of sites will stay relatively steady in the future if human effects are the largest threat, due to the poor soil quality and difficult access associated with the species' habitat. But, Lobdell and Thompson did find two historical sites unoccupied during their recent exploration; it is hard to know if this decline will continue.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:1000Continuing decline of mature individuals:Yes
Continuing decline in subpopulations:Yes

Habitat and Ecology [top]

Habitat and Ecology:Q. oglethorpensis is found in moist, heavy chalk or limestone soils that are rich and contain high clay content. The tree usually reaches about 18 m, but can grow up to 25 m (Louisiana Dept. of Wildlife and Fisheries). The species' most vigorous subpopulations exist within the distinctive Piedmont Gabbro Upland Depression Forest (PGUDF) ecosystem, as defined by the International Terrestrial Ecological Systems Classification (ITESC) system. This association consists of a patchy, wet hardwood forest only occurring on gently sloping or slightly concave upland terrain in Georgia and South Carolina. In 2014, a vouchered floristic inventory surveyed three of these sites within Oconee National Forest of Jasper County, Georgia, which included about 3 km2 total (Sewell and Zomlefer 2014). Haehnle and Jones found in 1985 that extensive agriculture within the Piedmont region prior to the 1950's had mostly restricted Q. oglethorpensis to roadsides and fence rows when found outside protected areas. This likely means that Oglethorpe Oak had a denser population before colonial settlement.

Associated species recorded by Jordan Wood in 2016 during his exploration across Oglethorpe Oak's range include: Acer floridanum, Acer rubrum, Aralia spinosa, Carya ovata, Carya tomentosa, Carya glabra, Celtis sp., Cornus alternifolia, Cornus florida, Crataegus marshallii, Fraxinus sp., Ilex sp., Juglans nigra, Juniperus virginiana, Liquidambar styraciflua, Nyssa sylvatica, Pinus taeda, Quercus alba, Q. shumardii, Q. stellata, Q. marilandica, Q. nigra, Q. pagoda, Q. phellos, Q. laurifolia, Q. sinuata, Q. falcata, Q. austrina, Q. michauxii, Q. muehlenbergii, Q. marilandica, Tillandsia usenoides, Toxicodendron radicans, Ulmus alata, U. americana and Viburnum sp.

Threats [top]

Major Threat(s): It is believed currently that land-use changes pose that largest threat to Q. oglethorpensis, but most areas that could be cleared for agriculture, silviculture, or urban development have already been converted, leaving wetter areas or road-side occurrences remaining (Lobdell and Thompson 2016, Haehnle and Jones 1985). Damming and flooding in some areas have changed the floodplain ecosystems relied upon by Oglethorpe Oak, and invasive plants such as Japanese Honeysuckle (Lonicera japonica), Autumn Olive (Elaeagnus umbellata), and Chinese Privet (Ligustrum sinense) compete with seedlings, threatening the long-term viability of the species (Chafin 2007). Changes in the hydrology of the region have lead to insubstantial regeneration, and serious losses due to Chestnut Blight (Cryphonectria parasitica), which cannot survive in wetland sights therefore attacking upon drainage. There is no evidence of Oglethorpe Oak spreading to new areas, or reviving declining subpopulations (Coder 2003).  

According to Coder (2003), from 1940 to 1990, about 10% of known Q. oglethorpensis trees were lost to habitat destruction and disease. Dry-season fires pose a further concern, since Oglethorpe Oak seedlings and saplings are fire-intolerant. Within the November 2016 issue of the National Significant Wildland Fire Potential Outlook, predictions show the southeastern U.S. continuing "to see a large area of above normal significant fire potential for November and December." Severe drought as well as stronger winds persist this fall and winter across the southeast U.S., with the worst conditions extending across Alabama, Georgia, Mississippi and the western Carolinas. Prior to this dry season, Hurricane Matthew brought heavy rain and extensive flooding to the Carolinas, with the Southeast Coast receiving over 200% of normal rainfall for the month of October. These extreme wet and dry events seem to be increasing with climate change, and could become a detrimental threat to Q. oglethorpensis.

Conservation Actions [top]

Conservation Actions: Three protected areas currently monitor and manage Q. oglethorpensis within their boundaries, performing controlled burns and selective clearing; these include Bienville National Forest in Mississippi, Oconee National Forest in Georgia, and Sumter National Forest in South Carolina.

In 2015, through a joint conservation initiative of the US Forest Service and the American Public Gardens Association, seed and/or samples of scion wood were collected from populations of the species in Mississippi, Alabama, Georgia, and South Carolina, totaling 28 samples. These samples are in propagation at The Morton Arboretum (Lisle, IL), and will be distributed to five arboreta and botanical gardens: Chicago Botanic Garden (Glencoe, IL), Starhill Forest Arboretum (Petersburg, IL), Holden Arboretum (Willoughby, OH), Donald E. Davis Arboretum of Auburn University (Auburn, AL) and Moore Farms Botanical Garden (Lake City, SC). Through cultivation in these Nationally Accredited Collections, a genetically diverse and representative germplasm of Quercus oglethorpensis will be preserved, potentially utilized in future reintroduction efforts, utilized within further research initiatives (Lobdell and Thompson 2016).

According to Botanic Gardens Conservation International (BGCI), 29 gardens and arboreta throughout the globe cultivate this species within their ex-situ collections (2016).

Citation: Beckman, E. 2017. Quercus oglethorpensis. The IUCN Red List of Threatened Species 2017: e.T30956A2798949. . Downloaded on 20 September 2018.
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