Home/Species/ Bur Oak

Quercus macrocarpa

Michx.

Bur Oak

G5Secure Found in 8 roadless areas NatureServe Explorer →

G5SecureGlobal Rank

Least concernIUCN

LowThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.158441

Element CodePDFAG05190

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

IUCNLeast concern

Endemicoccurs (regularly, as a native taxon) in multiple nations

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderFagales

FamilyFagaceae

GenusQuercus

Other Common Names

bur oak (EN) Chêne à gros fruits (FR)

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Taxonomic Comments

Flora North America does not recognize Q. macrocarpa var. depressa as a distinct variety, while Kartesz (1999) does.

Conservation Status

Rank MethodLegacy Rank calculation - Excel v3.1x

Review Date2018-05-25

Change Date1983-09-06

Edition Date2018-05-25

Edition AuthorsTreher (2018)

Threat ImpactLow

Range Extent>2,500,000 square km (greater than 1,000,000 square miles)

Number of Occurrences> 300

Rank Reasons

Quercus macrocarpa is a wide ranging species in North America, occurring across most of the eastern United States and southern Canada. The number of occurrences and population size can't be quantified with available data, but it is believed to be abundant throughout most of its range. While there are threats to this species in parts of the range, the overall impact is low. Some treatments recognize two varieties (var. depressa and var. macrocarpa). Not enough information is available to assess variety depressa at this times, so individual assessments of varieties are incomplete. Most of the range is attributed to var. macrocarpa.

Range Extent Comments

Quercus macrocarpa occurs in eastern temperate North America including the north-central United States and eastern Great Plains, as far south as Texas and Alabama and as far east as Maryland and Pennsylvania and northward to Maine. It extends even farther north into south-central and southeastern Canada.

Occurrences Comments

While the number of occurrences for this species is unknown, there are expected to be over 300 rangewide.

Threat Impact Comments

Known threats to this species include: conversion of land to agricultural use, livestock introductions, and active fire suppression. The species has declined on savannas and prairies due to grazing and fire suppression. Fire suppression causes a shift in species, to more shade-tolerant maple-basswood forests. There are few insects or diseases that cause serious damage to the species (Kenny and Wenzell 2015).

Ecology & Habitat

Description

Bur Oak is a small to large tree. Its bark is deeply furrowed and twigs are stout. The alternate, oblong-elliptic leaves are 10-20 cm in length and are deeply to shallowly lobed, with the terminal lobe being the largest. Leaves are dark green and shiny above but silvery below with fine, star-shaped hairs. Male flowers of 5-10 stamens are borne in long, loose, pendulous inflorescences from the leaf axils. 1 to several female flowers occur in the axils of new leaves. The acorn is up to 2-4 cm long, ellipsoidal, and the top half or more is enclosed by a roughened, fringe-margined cup.

Diagnostic Characteristics

This is Montana's only native oak.

Habitat

Quercus macrocarpa is typically found on limestone or calcareous clay but in a wide range of habitats including bottomlands, riparian slopes, poorly drained areas, prairies and in a variety of moisture regimes. The species can tolerate fairly dry and cold conditions: in the northwestern portion of its, it occurs on dry slopes and ridges, prairies (FNA 1997; Kenny and Wenzell 2015).

Ecology

This species is one of the most cold tolerant and drought resistant oaks (Kenny and Wenzell 2015).

Terrestrial Habitats

Forest/WoodlandGrassland/herbaceous

Palustrine Habitats

Riparian

Other Nations (2)

United StatesN5

Province	Rank	Native
Pennsylvania	S3	Yes
Tennessee	SNR	Yes
South Dakota	S5	Yes
Wisconsin	SNR	Yes
New Jersey	SNR	Yes
Connecticut	SU	Yes
Vermont	S4	Yes
Kentucky	SNR	Yes
West Virginia	S4	Yes
Louisiana	S1	Yes
Arkansas	SNR	Yes
New Hampshire	S1	Yes
Wyoming	S3	Yes
Iowa	S5	Yes
Mississippi	S2	Yes
Minnesota	SNR	Yes
Delaware	SNA	No
Virginia	S1	Yes
Montana	S2	Yes
Texas	SNR	Yes
Maryland	S1	Yes
New Mexico	SNR	Yes
Illinois	S5	Yes
Massachusetts	S3	Yes
District of Columbia	S1	Yes
Nebraska	SNR	Yes
Maine	SNR	Yes
New York	S4	Yes
Indiana	S5	Yes
Missouri	SNR	Yes
Alabama	S2	Yes
North Carolina	SNR	Yes
Michigan	SNR	Yes
Ohio	SNR	Yes
Rhode Island	SNR	Yes
Oklahoma	SNR	Yes
Kansas	S5	Yes
North Dakota	SNR	Yes

CanadaN5

Province	Rank	Native
Ontario	S5	Yes
Alberta	SU	Yes
Quebec	S4	Yes
Manitoba	S5	Yes
Saskatchewan	S5	Yes
New Brunswick	S2	Yes

Threat Assessments

Threat	Scope	Severity	Timing
1 - Residential & commercial development	Unknown	Unknown	High (continuing)
2 - Agriculture & aquaculture	Small (1-10%)	Extreme - moderate	High (continuing)
7 - Natural system modifications	Small (1-10%)	Serious - moderate	High (continuing)
7.1 - Fire & fire suppression	Small (1-10%)	Serious - moderate	High (continuing)
8 - Invasive & other problematic species, genes & diseases	Large (31-70%)	Slight or 1-10% pop. decline	High (continuing)

Plant Characteristics

DurationPERENNIAL, DECIDUOUS

Economic Value (Genus)No

Roadless Areas (8)

Idaho (1)

Area	Forest	Acres
Bear Creek	Caribou-Targhee National Forest	118,582

Indiana (1)

Area	Forest	Acres
Mogan Ridge	Hoosier National Forest	8,435

Minnesota (1)

Area	Forest	Acres
Hegman Lakes	Superior National Forest	675

North Dakota (2)

Area	Forest	Acres
Sheyenne	Dakota Prairie Grasslands	14,537
Venlo	Dakota Prairie Grasslands	5,317

South Dakota (2)

Area	Forest	Acres
Beaver Park	Black Hills National Forest	5,010
Indian Creek	Buffalo Gap National Grassland	24,666

Texas (1)

Area	Forest	Acres
Big Creek	National Forests in Texas	1,447

References (6)

Flora of North America Editorial Committee (FNA). 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.
Heidel, B.L. 1993. Survey for QUERCUS MACROCARPA in the Powder River Resource Area, Miles City District, Bureau of Land Management, Montana. Unpublished report to the Bureau of Land Management, Miles City District. Montana Natural Heritage Program, Helena, MT. 13 pp. plus appendices.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Kenny, L., and K. Wenzell. 2015. <i>Quercus macrocarpa</i>. The IUCN Red List of Threatened Species 2015: e.T33991A2839807. Online. Available: http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T33991A2839807.en (accessed 25 May 2018).
Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.
Severson, K.E. and J.K. Kranz. 1978. Management of burr oak on deer winter range. Wildlife Society Bulletin 6:212-216.

Quercus macrocarpa

Description

Diagnostic Characteristics

Habitat

Ecology

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