Common (Translated Scientific) Name: Alligator Juniper - Texas Red Oak / Evergreen Sumac Madrean-Balconian Forest & Woodland Division
Colloquial Name: Madrean-Balconian Forest & Woodland
Hierarchy Level: Division
Type Concept: This division is composed of forests, woodlands, and savannas characterized by various species of conifers and deciduous and evergreen broad-leaved trees that have a Madrean and/or Balconian distribution, in semi-arid to sub-humid, warm-temperate settings in montane areas of southern New Mexico, southeastern Arizona, western Texas, and northern and central Mexico (Madrean) and in lowland settings in central Texas, mostly on the Edwards Plateau and environs (Balconian). The genera Juniperus (including Juniperus ashei, Juniperus deppeana), and Quercus (Quercus arizonica, Quercus buckleyi, Quercus emoryi, Quercus fusiformis, Quercus grisea, Quercus hypoleucoides, and others), including a number of evergreen species, are well represented throughout, and Pinus spp. (Pinus arizonica, Pinus cembroides, Pinus ponderosa var. scopulorum, Pinus strobiformis, and others) are a major component of the Madrean portion of the division. Arbutus spp. and Acer grandidentatum are less frequent, but widespread, taxa. Other tree genera that can be dominant include Pseudotsuga and Abies in the Madrean portion and Fraxinus, Prunus, Ulmus, Celtis, and Juglans in the Balconian portion. The shrub layer often has succulent species, including frequent members of the families Liliaceae, Agavaceae, and Cactaceae (Nolina, Dasylirion, Yucca, Agave, Opuntia), and the herbaceous layer frequently is dominated by warm-season (C4) grasses.
Diagnostic Characteristics: The division is generally characterized by the importance of evergreen broad-leaved trees and shrubs, including Quercus spp., by a preponderance of warm-season (C4) species among the grasses (Poaceae) that may be present, and by the frequent presence of semi-succulent subshrubs in the families Liliaceae and/or Agavaceae (e.g., Agave, Dasylirion, Nolina, Yucca). Few individual species span the USNVC range of this division; the tree genera Pinus, Juniperus, Quercus and shrub and herb genera Bouteloua, Dasylirion, Nolina, and (in the Madrean portion) Muhlenbergia are relatively important. Tree taxa that are strong diagnostics of the Madrean part of this division within the scope of the USNVC (by decreasing constancy) include Juniperus coahuilensis, Juniperus coahuilensis var. arizonica, Juniperus flaccida, Pinus arizonica, Pinus engelmannii, Pinus leiophylla, Pinus cembroides, Pinus discolor, Quercus gravesii, Quercus oblongifolia, Quercus hypoleucoides, Quercus rugosa, Quercus pungens (in the strict sense), and Arbutus arizonica. Moderately diagnostic Madrean tree taxa (highly diagnostic when important or codominant) include Juniperus deppeana, Quercus grisea, Quercus arizonica, and Quercus emoryi. Strongly diagnostic Balconian tree taxa include Fraxinus albicans, Juniperus ashei, Quercus buckleyi, Quercus fusiformis, Quercus vaseyana, and Ulmus crassifolia. The ranges of Arbutus xalapensis, Pinus remota, and Quercus laceyi span the western Balconian and the eastern Madrean regions. Diagnostic shrub (to small tree) species that are relatively widespread throughout the U.S. part of the division include Aloysia gratissima, Diospyros texana, Eysenhardtia texana, Mahonia trifoliolata, Rhus virens, and Ungnadia speciosa. The genera Nolina, Dasylirion, and Agave are moderately diagnostic subshrubs of this division among forest and woodland divisions of the USNVC; most individual species, listed in the Floristics section, are limited either to the Madrean or Balconian region.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: Higher-elevation stands that are dominated by needle-leaved conifers (e.g., most of Madrean Montane Forest & Woodland Macrogroup (M011)) might be better assigned to a cool-temperate division. Brown et al. (1979), Pase and Brown (1994), and Brown et al. (1998) followed this approach for Madrean montane forests, based on their floristic and climate similarities to other cold-temperate forests and woodlands. Average annual temperatures given by Morafka (1977) for higher-elevation stands that represent this vegetation are more consistent with cool-temperate sites than with warm-temperate sites. The cool-temperate Madrean Montane Conifer Forest of Brown et al. (1998) includes a Douglas Fir Mixed Conifer Series (122.81) and a Yellow Pine Series (122.82), which appear to best fit patterns of dominance by species identified as components of M011 (Pseudotsuga menziesii, Pinus strobiformis, Pinus arizonica, Abies concolor, Abies coahuilensis), as well as by other species of higher montane settings in Madrean settings in northern Mexico [see Floristics section]. Additionally, these species or closely related congeners are significant components of divisions within 1.B.2 Cool Temperate Forest & Woodland Formation (F008) (e.g., 1.B.2.Nb in the southern Rocky Mountains and 1.B.2.Nd in the Sierra Nevada). As in cool-temperate forests in the Sierra Nevada, the occurrence of some warm-temperate elements in subordinate strata (e.g., Arctostaphylos or evergreen species of Quercus) in these higher montane Sierra Madrean forests may be more a function of overall high regional diversity in these taxonomic groups (and, thus, some individual cold-adapted species) than of high diagnostic value for the vegetation within the higher-elevation forests. For consistency with classifications of other U.S. montane vegetation and with prior work, M011 might best be grouped with Mexican vegetation that meets the criteria of Madrean montane (122.8) or Madrean subalpine (121.6) of Brown et al. (1998) or Madrean and Mexican Highlands pine and fir forests as a distinct macrogroup(s) within 1.B.2.Nd or perhaps within a Madrean or Madrean-Transvolcanic cool-temperate forest and woodland division. The concept of M011 is primarily of Mexican distribution and of very limited extent within the scope of the USNVC, and there is considerable floristic gradient across the latitudinal range of both Madrean cordilleras (e.g., Peet 1988). Since the concept clearly has some cool-temperate forests and woodlands, the treatment of the full range of Madrean warm- and cool-temperate forests and woodlands would best be investigated with consideration of information from Mexico.
The merging of the Madrean macrogroups with the Balconian macrogroup within this division is a somewhat uncomfortable fit. The two regions share no tree species that are dominant across large portions of either, and some of the nominal species have no range overlap. Solutions that might be explored in the future include subsuming the Balconian M015 within 1.B.1.Na Southeastern North American Forest & Woodland Division (D006), since there is more (albeit still somewhat limited) sharing of tree species. The treating of the content of M015 as a Balconian or Comanchian (sensu Dice 1943) division may be justified, since most of its dominant tree species are not shared extensively with geographically neighboring divisions that represent upland forest and woodland vegetation.
Similar NVC Types:
D008 Eastern North American Forest & Woodland, note: may intergrade with stands of D060 classified to ~Balconian Forest & Woodland Macrogroup (M015)$$ in the southern Cross Timbers area of north-central Texas.
D010 Western North American Pinyon - Juniper Woodland & Scrub, note: may intergrade with stands of D060 classified to ~Madrean Lowland Evergreen Woodland Macrogroup (M010)$$ in the north. The tree species Juniperus monosperma and/or Pinus edulis may be shared between the divisions.
D006 Southeastern North American Forest & Woodland, note: may intergrade with stands of D060 classified to ~Balconian Forest & Woodland Macrogroup (M015)$$ near its eastern limits. The southeastern D006 generally is composed of stands with taller trees that are more mesic in tolerance and that more frequently exhibit complete canopy closure. The southeastern tree species Quercus muehlenbergii, Prunus serotina, Ulmus crassifolia, Quercus stellata, Quercus marilandica, Aesculus pavia, Lindera benzoin, and Cercis canadensis may be shared between the divisions. In addition to the diagnostic Balconian species, species with western affiliations such as Acer grandidentatum, Diospyros texana, Quercus mohriana, Juglans major, and Prosopis glandulosa generally will also indicate D060.
D194 Rocky Mountain Forest & Woodland, note: may intergrade with stands of D060 classified to ~Madrean Montane Forest & Woodland Macrogroup (M011)$$ in the north (e.g., along the Mogollon Rim). Tree species such as Pinus ponderosa, Pseudotsuga menziesii, Abies concolor, and/or Acer grandidentatum and shrub species Quercus turbinella, Quercus gambelii, Cercocarpus montanus, and others are shared between the divisions. The two units may also intergrade in the higher elevations of the higher "sky island" ranges in southeastern Arizona (e.g., Pinaleno and Chiricahua mountains), where a predominance by Rocky Mountain species (e.g., Picea engelmannii, Populus tremuloides, Abies lasiocarpa var. arizonica) is diagnostic of D194.
Physiognomy and Structure: Vegetation structure ranges from savannas and woodlands (5-60% tree cover), composed of relatively short (3-15 m tall) trees (predominant at lower elevations) to woodlands and closed-canopy forests (40-100% tree cover), composed of taller (15-30 m tall) mostly evergreen (occasionally deciduous), scale-leaved, needle-leaved and/or broad-leaved trees (predominant at higher elevations). A shrub layer usually is present and ranges from sparse (usually) to dense; it may be composed of deciduous and/or evergreen woody species; succulent shrubs or semi-succulent subshrubs are often a significant component. An herbaceous layer is almost always present and typically is dominated by shade-intolerant grasses (Poaceae) (>25% cover). The abundance of grasses is variable and is somewhat negatively correlated with elevation and with tree canopy closure. A wide variety of forb species, typically with low overall cover, may be present.
Floristics: The floristics of this division are diverse, with significant turnover in species between the Madrean (macrogroups M10 and M011) and the Balconian (macrogroup M015) components of this division. Within each of the Madrean macrogroups a significant number of species are restricted to either the western Madrean (the Sierra Madre Occidental and its northern extensions) in the U.S. part of the range, or the eastern Madrean (the Sierra Madre Oriental and its northern extensions) regions. These western to eastern differences may prove to be more pronounced when the Mexican portion of the Madrean range is examined. Outside of the U.S., there is considerable additional species turnover along a north-to-south latitudinal gradient; the southern boundary of the division (presumably in Mexico) is not well understood.
In the Madrean (western) part of this division, characteristic tree taxa that are relatively widespread across the United States portion of the division include Acer grandidentatum, Cupressus arizonica (= Hesperocyparis arizonica), Juniperus deppeana, Pinus arizonica, Pinus cembroides, Pinus ponderosa var. scopulorum, Pinus strobiformis, Pseudotsuga menziesii, Quercus grisea, Quercus arizonica, Quercus emoryi, and Quercus hypoleucoides. Characteristic species of the western portion of the United States range of the division (southeastern Arizona and southwestern New Mexico) include Abies concolor, Arbutus arizonica, Juniperus coahuilensis var. arizonica (= Juniperus arizonica), Pinus discolor, Pinus engelmannii, Pinus leiophylla, Quercus chrysolepis, Quercus oblongifolia, and Quercus viminea. In the eastern (southeastern New Mexico and western Texas) portion of the range, Arbutus xalapensis, Juniperus coahuilensis (in the strict sense), Juniperus flaccida, Juniperus pinchotii, Pinus remota, Quercus gravesii, and Quercus muehlenbergii are characteristic. In northern Mexico (Sonora, Chihuahua, Coahuila), Abies durangensis, Cupressus lusitanica (= Hesperocyparis lusitanica), Juniperus durangensis, Picea chihuahuana, Pinus douglasiana, Pinus durangensis, Pinus herrerae, Pinus lumholtzii, Pinus maximinoi, Pinus oocarpa, Pinus teocote, Pinus yecorensis, Quercus albocincta, Quercus chihuahuensis, Quercus coccolobifolia (= Quercus jonesii), Quercus mcvaughii, and Quercus tuberculata are additional tree components in the Sierra Madre Occidental, as are Abies coahuilensis and Quercus greggii in the Sierra Madre Oriental. At the northern end of the Madrean range, Juniperus monosperma and/or Pinus edulis may be important.
In the Edwards Plateau (eastern) part of the division, the most abundant and frequent tree species include Fraxinus albicans (= Fraxinus texensis), Juniperus ashei, Quercus fusiformis, Prunus serotina var. eximia, Quercus buckleyi, Quercus laceyi, and Ulmus crassifolia. Other important, and often locally dominant, species are Arbutus xalapensis, Celtis laevigata var. laevigata, Celtis laevigata var. reticulata, Juglans major, Juglans nigra, Pinus remota, Prosopis glandulosa, Quercus marilandica, Quercus muehlenbergii, Quercus stellata, Quercus sinuata var. breviloba, and Quercus vaseyana (= Quercus pungens var. vaseyana).
Relatively few tree species are shared between the Madrean and Balconian portions of this division. Several that may be dominant in stands have ranges that span from the western Balconian to the eastern Madrean, but have limited ranges within each region (e.g., Pinus remota, Quercus laceyi, Juniperus pinchotii). Several others have wider ranges across both component regions, but tend to be minor or somewhat inconstant species (e.g., Acer grandidentatum, Arbutus xalapensis, Quercus muehlenbergii).
Characteristic shrub species, listed with their respective primary affinities to either the western Madrean (wM), eastern Madrean (eM), and/or Balconian (B) regions include Forestiera pubescens (all regions), Aloysia gratissima (all), Mahonia trifoliolata (all), Nolina texana (all), Ptelea trifoliata (all), Rhus virens (all), Agave palmeri (wM), Arctostaphylos pungens (wM), Mimosa dysocarpa (wM), Purshia mexicana (wM), Quercus toumeyi (wM), Yucca schottii (wM), Acacia angustissima (wM, eM), Ceanothus greggii (wM, eM), Cercocarpus montanus (wM, eM), Dasylirion wheeleri (wM, eM), Garrya wrightii (wM, eM), Mimosa aculeaticarpa var. biuncifera (wM, eM), Nolina microcarpa (wM, eM), Quercus gambelii (wM, eM), Quercus grisea (wM, eM), Quercus pungens (in the strict sense) (wM, eM), Quercus turbinella (wM, eM), Rhus trilobata (in the strict sense) (wM, eM), Yucca baccata (wM, eM), Agave havardiana (wM), Chrysactinia mexicana (eM, B), Dasylirion leiophyllum (eM), Nolina erumpens (eM), Quercus mohriana (eM), Salvia regla (eM), Viguiera stenoloba (eM), Yucca torreyi (eM), Eysenhardtia texana (eM, B), Garrya ovata (eM, B), Sophora secundiflora (eM, B), Ungnadia speciosa (eM, B), Aesculus pavia (B), Ageratina havanensis (= Eupatorium havanense) (B), Cercis canadensis var. texensis (B), Dasylirion texanum (B), Diospyros texana (B), Frangula caroliniana (= Rhamnus caroliniana) (B), Lindera benzoin (B), Opuntia engelmannii var. lindheimeri (B), Opuntia leptocaulis (B), Prunus mexicana (B), Rhus aromatica (in the strict sense) (B), Sideroxylon lanuginosum (B), Viburnum rufidulum (B), Yucca rupicola (B), and Ziziphus obtusifolia var. obtusifolia (B).
The herbaceous layer is typically diverse with variable cover, but is usually prominent, especially in interspaces between trees or mottes in open woodlands. Dominant species are graminoids such as Aristida purpurea (all), Bothriochloa laguroides (all), Bouteloua curtipendula (all), Bouteloua gracilis (all), Bouteloua hirsuta (all), Digitaria californica (all), Leptochloa dubia (all), Schizachyrium scoparium (all), Bromus ciliatus var. richardsonii (= Bromus richardsonii) (wM), Bouteloua rothrockii (wM), Carex geophila (wM), Muhlenbergia longiligula (wM), Muhlenbergia virescens (wM), Eragrostis intermedia (wM, eM), Koeleria macrantha (wM, eM), Muhlenbergia emersleyi (wM, eM), Muhlenbergia pauciflora (wM, eM), Muhlenbergia tenuifolia (wM, eM), Nassella tenuissima (= Stipa tenuissima) (wM, eM), Piptochaetium fimbriatum (wM, eM), Piptochaetium pringlei (wM, eM), Poa fendleriana (wM, eM), Schizachyrium cirratum (wM, eM), Muhlenbergia setifolia (eM), Hilaria belangeri (wM, B), Andropogon gerardii (B), Aristida oligantha (B), Muhlenbergia lindheimeri (B), Bothriochloa laguroides (B), Carex planostachys (B), Nassella leucotricha (B), and Sorghastrum nutans (B). Forbs are both diverse and variable between regions.
Dynamics: Natural fire has been an important factor in the trajectory of stand structure and species composition. More frequent and/or hotter fires favor the development of more open woodlands and savannas over denser woodlands and forests. Frequent and hotter fires also favor oaks over less fire-resistant species, such as junipers and, in the Madrean region, some pines that require several decades in order to develop bark of fire-resistant thickness (Barton et al. 2001). The decreased frequency of fire due to active suppression and reduction of fine fuels by livestock grazing during the 20th century evidently has favored an increase of junipers and other more fire-sensitive species over oaks and has increased tree density in many stands in both the Edwards Plateau (Fonteyn et al. 1988) and the Madrean region (Turner et al. 2003). Additionally, Fonteyne et al. (1988) found that prescribed fires on the Edwards Plateau, as now conducted mainly during the winter months, burn cooler than do lightning-ignited, summer fires (which are currently usually suppressed) and are thus less effective at selecting against juniper.
The frequency and persistence of drought periods is a factor that limits the distribution and abundance of more moisture-demanding species such as pines in the Madrean region (Barton 1993). Livestock grazing is currently a common use of stands that can affect their structure and composition. Grazing and browsing by native ungulates, outbreaks of plant pathogens and insect herbivores, fuelwood harvesting, and chaining are other processes that have affected stand composition and structure. The descriptions for individual macrogroups of this division document more specific effects of these processes across the regional and elevation gradients within the division.
Environmental Description: Stands representing this division occur as matrix vegetation in foothills, mountains and plateaus in the relatively wide cordillera of both the Sierra Madre Occidental and Sierra Madre Oriental in Mexico. The vegetation extends northwest in less extensive and more isolated ranges ("sky islands") within the basins of the Chihuahuan and Sonoran deserts in Trans-Pecos Texas, southern New Mexico and southeastern Arizona. It also extends northeast from the Sierra Madre Oriental as a more continuous band into the Edwards Plateau of Texas (and sparingly into the Cross Timbers Region of northern Texas). Within the scope of the USNVC, elevation generally ranges from 1300 to 2700 m (4225-8775 feet) in the Madrean part of the range (possibly to 3700 m [12,025 feet] in Mexico) and from 30 m to about 1000 m (100-3250 feet) in the Balconian part of the range. Stands occur on a variety of upland (nonriparian) topographic settings, from canyon bottoms to tops of ridges and mesas. At the lowest elevations, stands occur within a mosaic of grassland or scrub, usually occupying the rockier substrates or along drainages.
Climate: The climate is generally warm temperate and arid, transitioning to cool-temperate conditions at higher elevations (e.g., above 2200 m [7150 feet]) and transitioning to semi-arid to sub-humid conditions in the eastern part of the range (Riskind and Diamond 1988). Estimated average annual temperatures are 15-17°C (59-63°F) for pinyon-juniper woodlands (i.e., M010) and 9.5 to 13°C (49-55°F) for montane pine forests (i.e., M011) in the Sierra Madre Oriental (Morafka 1977), and 18-21°C (64-71°F) across the Edwards Plateau. The Edwards Plateau experiences an average of 230-260 frost-free days per year (Riskind and Diamond 1988). Annual precipitation ranges from 35 to 85 cm (14-33 inches) per year at elevations below 2000 m (6500 feet) (Riskind and Diamond 1988, Brown 1994c) and from 50 to 110 cm (20-43 inches) at elevations from 2000 to 3000 m (6500-9725 feet) (Pase and Brown 1994). Precipitation in the western (Madrean) portion of the division's range is fairly strongly seasonally distributed, with 40-70% of the total occurring during the months of July, August, and September; in the eastern (Balconian) portion of the range, precipitation is more evenly distributed (Riskind and Diamond 1988).
Soils/substrate: Soils and substrates are highly diverse, spanning a large variety of geologic substrates.
Biogeography: Stands of this division are found in the higher elevations of the Chihuahuan and Madrean [floristic] provinces, and in the southern part of the Comanchian Subprovince of the Great Plains Province of McLaughlin (2007). In the context of Dice (1943), they occupy the higher elevations of the Apachian and Chihuahuan [biotic] provinces, and in the southern part of the Comanchian Subprovince. Within Texas, they occupy the Balconian and the highest elevations of the Chihuahuan [biotic] Provinces of Blair (1950).
Geographic Range: This division occurs in northern and north-central Mexico in the main cordillera of the Sierra Madre Occidental and Sierra Madre Oriental. The vegetation extends north in increasingly more insular patches in more isolated mountain ranges within the Chihuahuan and the eastern Sonoran deserts in northernmost Mexico and into southeastern Arizona (generally south of the Mogollon Rim), southern New Mexico, and western (Trans-Pecos) Texas. It also extends east in more continuous stands at lower elevations through the Stockton and Edwards plateaus, the Llano Uplift, and the Lampasas Cut Plain of Texas.
Nations: MX, US
States/Provinces: AZ, MXCH, MXCO, MXSO, NM, TX
|US Forest Service Ecoregions (2007)|
Southwest Plateau and Plains Dry Steppe and Shrub Province
Confident or certain
Confident or certain
Omernik Ecoregions: 23:C, 24:C, 30:C, 79:C
Confidence Level: Moderate
Confidence Level Comments:
Synonomy: > combination of Madrean Evergreen Forest and Woodland (123.3), Relict Conifer Forest (123.4) (in part), and Madrean Montane Conifer Forest (122.8) (in part) (Brown et al. 1998)
> combination of Madrean Evergreen Forest and Woodland (123.3), Relict Conifer Forests and Woodlands (123.5) (in part), and Madrean Montane Conifer Forest (122.6) (in part) (Brown et al. 1979)
Concept Author(s): D.E. Brown, F. Reichenbacher, and S. E. Franson (1998)
Author of Description: C. Lea
Acknowledgements: The description incorporated much floristic information from macrogroup descriptions as provided by Keith Schulz, Esteban Muldavin, Judy Teague, and Milo Pyne. Lee Elliott, David Diamond, and Bruce Hoagland provided useful comments and information that assisted in the delineation of this unit.
Version Date: 08Jan2016
- Amos, B., and C. Rowell, Jr. 1988. Floristic geography of woody plants. In: B. B. Amos and F. R. Gehlbach, editors. Edwards Plateau vegetation: Plant ecological studies in central Texas. Baylor University Press, Waco, TX.
- Barton, A. M. 1993. Factors controlling plant distributions: Drought, competition, and fire in montane pines in Arizona. Ecological Monographs 63:367-397.
- Barton, A. M., T. W. Swetnam, and C. H. Baisan. 2001. Arizona pine (Pinus arizonica) stand dynamics: Local and regional factors in a fire-prone Madrean gallery forest of southeast Arizona, USA. Landscape Ecology 16:351-369.
- Blair, W. F. 1950. The biotic provinces of Texas. Texas Journal of Science 2:93-117.
- Brown, D. E. 1994c. Madrean evergreen woodland. Pages 59-65 in: D. E. Brown, editor. Biotic communities: Southwestern United States and northwestern Mexico. University of Utah Press, Salt Lake City, UT.
- Brown, D. E., C. H. Lowe, and C. P. Pase. 1979. A digitized classification system for the biotic communities of North America with community (series) and association examples for the Southwest. Journal of the Arizona-Nevada Academy of Science 14:1-16.
- Brown, D. E., F. Reichenbacher, and S. E. Franson. 1998. A classification of North American biotic communities. The University of Utah Press, Salt Lake City. 141 pp.
- Dice, L. R. 1943. The biotic provinces of North America. University of Michigan Press, Ann Arbor.
- Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2017a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Fonteyn, P. J., M. W. Stone, M. A. Yancy, J. T. Baccus, and M. Nadkarni. 1988. Forests and woodlands of the Northeastern Balcones Escarpment. Pages 79-90 in: B. B. Amos and F. R. Gehlbach, editors. Edwards Plateau vegetation: Plant ecological studies in central Texas. Baylor University Press, Waco, TX.
- Gehlbach, F. R. 1988. Forests and woodlands of the Northeastern Balcones Escarpment. Pages 27-77 in: B. B. Amos and F. R. Gehlbach, editors. Edwards Plateau vegetation: Plant ecological studies in central Texas. Baylor University Press, Waco, TX.
- McLaughlin, S. P. 2007. Tundra to Tropics: The floristic plant geography of North America. Sida Botanical Miscellany Publication 30:1-58.
- Morafka, D. J. 1977. A biogeographical analysis of the Chihuahuan Desert through its herpetofauna. W. Junk, The Hague. 313 pp.
- Pase, C. P. and D. E. Brown, D. E. 1994. Rocky Mountain (Petran) and Madrean montane conifer forests. Pages 43-51 in: D. E. Brown, editor. Biotic communities: Southwestern United States and northwestern Mexico. University of Utah Press, Salt Lake City, UT.
- Peet, R. K. 1988. Forests of the Rocky Mountains. Pages 64-101 in: M. G. Barbour and W. D. Billings, editors. North American Terrestrial Vegetation. Cambridge University Press, New York.
- Powell, A. M. 1994. Grasses of the Trans-Pecos and adjacent areas. University of Texas Press, Austin. 377 pp.
- Powell, A. M. 1998. Trees and shrubs of the Trans-Pecos and adjacent areas. University of Texas Press, Austin. 498 pp.
- Riskind, D. H., and D. D. Diamond. 1988. An introduction to environments and vegetation. Pages 1-15 in: B. B. Amos and F. R. Gehlbach, editors. Edwards Plateau vegetation: Plant ecological studies in central Texas. Baylor University Press, Waco, TX.
- Tharp, B. C. 1939. The vegetation of Texas. Texas Academy of Science, Nontechnical Publication Series, Austin.
- Turner, R. M., R. H. Webb, J. E. Bowers, and J. R Hastings. 2003. The changing mile revisited: An ecological study of vegetation change with time in the lower mile of an arid and semiarid region. University of Arizona Press, Tucson.
- Van Auken, O. 1988. Woody vegetation of the southeastern escarpment and plateau. In: B. B. Amos and F. R. Gehlbach, editors. Edwards Plateau vegetation: Plant ecological studies in central Texas. Baylor University Press, Waco, TX.