Sierra Madre Oriental Pine-oak Forests Habitat
This taxon is found in the Sierra Madre Oriental pine-oak forests, which exhibit a very diverse community of endemic and specialized species of plants, mammals, reptiles and amphibians. These high mountains run north to south, beginning in the USA and ending in Mexico. The Sierra Madre Oriental pine-oak forests are a highly disjunctive ecoregion, owing to the fact that they are present only at higher elevations, within a region with considerable expanses of lower elevation desert floor.
The climate is temperate humid on the northeastern slope, and temperate sub-humid on the western slope and highest portions of the mountain range. Pine-oak forest habitat covers most of the region, even though most of the primary forest has been destroyed or degraded. However, the wettest portions house a community of cloud forests that constitute the northernmost patches of this vegetation in Mexico. The forests grow on soils derived from volcanic rocks that have a high content of organic matter. The soils of lower elevations are derived from sedimentary rocks, and some of them are formed purely of limestone. In the northernmost portions of the ecoregion, the forests occur on irregular hummocks that constitute biological "islands" of temperate forest in the middle of the Chihuahuan Desert. To the south, from Nuevo León southward until Guanajuato and Queretaro, the ecoregion is more continuous along the mainstem of the Sierra Madre Oriental.
Dominant tree species include the pines: the endemic Nelson's Pine (Pinus nelsonii), Mexican Pinyon (P. cembroides), Smooth-bark Mexican Pine (P. pseudostrobus), and Arizona Pine (P. arizonica); and the oaks Quercus castanea and Q. affinis. In mesic environments, the most common species are P. cembroides, and Alligator Juniper (Juniperus deppeana), but in more xeric environments on the west slopes of the mountains, the endemic P. pinceana is more abundant. Gregg's Pine (P. greggii) and Jelecote Pine (P. patula) are endemic.
Many mammalian species wander these rugged hills. Mule Deer (Odocoileus hemionus), Puma (Puma concolor), Cliff Chipmunk (Tamias dorsalis), Collared Peccary (Tayassu tajacu), Coati (Nasua narica), Jaguar (Panthera onca) and Coyote (Canis latrans) are a few of the many diverse mammals that inhabit this ecoregion. Some threatened mammals found in the ecoregion are: Bolaños Woodrat (Neotoma palatina VU); Diminutive Woodrat (Nelsonia neotomodon NT), known chiefly from the western versant of the Sierra Madre; Chihuahuan Mouse (Peromyscus polius NT); and Mexican Long-nosed Bat (Leptonycteris nivalis EN).
A considerable number of reptilian taxa are found in the Sierra Madre Oriental pine-oak forests, including three endemic snakes: Ridgenose Rattlesnake (Crotalus willardi); Fox´s Mountain Meadow Snake (Adelophis foxi); and the Longtail Rattlesnake (Crotalus stejnegeri VU), restricted to the central Sierra Madre. An endemic skink occurring in the ecoregion is the Fair-headed Skink (Plestiodon callicephalus). The Striped Plateau Lizard (Sceloporus virgatus) is endemic to the ecoregion. The Sonoran Mud Turtle (Kinosternon sonoriense VU) is found in the ecoregion and ranges from southwestern New Mexico south to northwestern Chihuahua.
The following anuran taxa occur in the Sierra Madre Oriental pine-oak forests: Red-spotted Toad (Anaxyrus punctatus); Cane Toad (Rhinella marina); Elegant Narrow-mouthed Toad (Gastrophryne elegans); New Mexico Spadefoot Toad (Spea multiplicata); Sinaloa Toad (Incilius mazatlanensis); Pine Toad (Incilius occidentalis); Southwestern Toad (Anaxyrus microscaphus); Woodhouse's Toad (Anaxyrus woodhousii); Great Plains Narrowmouth Toad (Gastrophryne olivacea); Great Plains Toad (Anaxyrus cognatus); Plateau Toad (Anaxyrus compactilis); Texas Toad (Anaxyrus speciosus); Sonoran Desert Toad (Incilius alvarius), found only at lower ecoregion elevations here; Rana-ladrona Silbadora (Eleutherodactylus teretistes); Sabinal Frog (Leptodactylus melanonotus); Mexican Leaf Frog (Pachymedusa dacnicolor); Montezuma Leopard Frog (Lithobates montezumae); Yavapai Leopard Frog (Lithobates yavapaiensis); Northwest Mexico Leopard Frog (Lithobates magnaocularis); Bigfoot Leopard Frog (Lithobates megapoda), who generally breeds in permanent surface water bodies; Mexican Cascade Frog (Lithobates pustulosus); Tarahumara Frog (Lithobates tarahumarae VU); Western Barking Frog (Craugastor augusti); Lowland Burrowing Frog (Smilisca fodiens); Taylor's Barking Frog (Craugastor occidentalis); Blunt-toed Chirping Frog (Eleutherodactylus modestus VU), found only at the very lowest elevations of the ecoregion; Shiny Peeping Frog (Eleutherodactylus nitidus); California Chorus Frog (Pseudacris cadaverina); Rio Grande Frog (Lithobates berlandieri); Madrean Treefrog (Hyla eximia); Mexican Treefrog (Smilisca baudinii); Dwarf Mexican Treefrog (Tlalocohyla smithii); Canyon Treefrog (Hyla arenicolor); Northern Sheep Frog (Hypopachus variolosus); Chiricahua Leopard Frog (Lithobates chiricahuensis). There are three salamanders found in the ecoregion: the endemic Sacramento Mountains Salamander (Aneides hardii), found only in very high montane reaches above 2400 meters; Tiger Salamander (Ambystoma tigrinum); and the Tarahumara Salamander (Ambystoma rosaceum).
Habitat and Ecology
Molecular Biology and Genetics
Barcode data: Pinus greggii
Statistics of barcoding coverage: Pinus greggii
Public Records: 3
Specimens with Barcodes: 11
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Pinus greggii's extent of occurrence is beyond the thresholds for a threatened category. The area of occupancy is more than 500 km2, but less than 2,000 km2. There are a total of eight locations and the population is severely fragmented. A substantial decline has occurred, and is continuing to occur, in the southern subpopulation (var. australis) which represents the majority of the total population. There is a lesser ongoing decline in the northern subpopulation (var. greggii). Consequently the species is assessed as Vulnerable.
- 2007Near Threatened (NT)
- 1998Data Deficient (DD)
- 1998Rare (R)
Pinus greggii, or Gregg's pine, is a small to medium high pine tree native to eastern Mexico, found in two distinct regions. It has an open crown and long and slender branches. The needles are in bundles of three with an average length of 11 cm. The cones are clustered in groups of 5 – 10. The branches en upper trunk is smooth. Pinus greggii is introduced in several countries.
Two varieties are found in literature:
- Pinus greggii Engelm. ex Parl. var. australis Donahue & Lopez
- Pinus greggii Engelm. ex Parl. var. greggii
The species name greggii honors Josiah Gregg (1806 – 1850), a merchant, explorer, naturalist, and author of the American Southwest and Northern Mexico.
Pinus greggiii is a small to medium high tree, reaching a height of 15 – 20 meters.
The bark remains smooth for a long time in this species, and only old trees have rough bark at the base of the trunk. The bark is thick, with deep, longitudinal fissures and rough, elongated plates. On the upper part of the trunk and branches smooth to finally scaly. Greyish brown.
The crown is loose and open.The branches are long and slender, swaying in the wind, spreading or curved downward, not pendulous, forming a rounded, dense or more open crown. The young twigs are bluish-green.
The winter buds are narrow and sharp pointed, without resin and with loose scales, usually light-brown.
Pollen cones are crowded near the proximal end of a new shoot. They are subtended by broad, scarious bracts, spreading, ovoid-oblong to cylindrical, 15 – 20 x 5 – 6 mm, yellowish, turning yellowish brown.
The seed cones are (6-)8 – 13(-15) x (4-)5 – 7 cm when open (width 3.5 – 5 cm when closed) , light-brown when ripe, long, closed, and curved. They have an irregular conical shape. They are found in clusters of 5 – 10 on the branches. In its native environment Pinus greggii begins flower and cone production at approximately 4 to 5 years of age. The cones ripen in December and January, approximately 21 months after pollination.
The apophysis has a marked transverse keel and a blunt umbo.
Pinus greggii is closely related to and has been crossed successfully with Pinus patula. The main morphological difference with the latter species is found in the needles: those of P. patula are longer and drooping. The bark is also different.
Pinus greggii is found in Mexico in the Sierra Madre Oriental, only in a limited area in the states of Coahuila, Nuevo León and Hidalgo. It occurs somewhat farther north than its close relative, Pinus patula, both ranges overlap slightly. About natural hybridization different opinions exist among specialists. Dvorak says that natural hybrids exist and that artificial hybrids have been successfully made. Farjon says that natural hybrids have not been reported.
Dvorak states that Pinus greggii occurs in two distinct geographic regions in Mexico: a northern population in the States of Coahuila and Nuevo León (24° to 25° N latitude), and a southern population in the States of Puebla, San Luis Potosí, Hidalgo, Querétaro, and Veracruz (20° to 21° N). There is a gap of 360 km between these two populations. There are differences in needle and cone morphology and seed size between the two populations. There are also differences in ecology and size of trees.
In its natural habitat Pinus greggiii grows in the cool highlands, at altitudes between 1300 – 2600 m; in the northern part of its distribution at 2300 – 2700m. Annual precipitation is 600 – 800 mm in much of its range, except on the east escarpment of the mountain ranges along the Hidalgo-Veracruz borderline, where it is 1000 – 1600 mm. In the north it is more often found on slightly alkaline soils (pH 7 – 8); in the south on acid soils (pH 4 – 5).
It has little resistance to frost conditions, but may endure a sporadic light frost where it occurs at its altitudinal limits. Usually the climate is rather humid in these mountains of northeastern Mexico.
It is nowhere abundant in its scattered range, and always occurred mixed with e.g. Quercus, Platanus, Liquidambar, Fraxinus, and other pines, like Pinus patula, P. pseudostrobus, P. teocote, P. montezumae, and P. arizonica var. stormiae; with P. cembroides and Juniperus flaccida on dry sites; and at higher and more mesic locations with Abies vejarii, Pseudotsuga menziesii or Cupressus lusitanica.
Cultivation and introductions
Pinus greggii from the southern population was introduced in approximately 10 countries in the subtropics between the 1960s and 1980s. Trials from both northern and southern populations were carried out in Brazil, Colombia, New Zealand, South Africa, and Zimbabwe in the late 1980s. These trials have resulted in plantations on a limited scale (e.g. 1000 ha per year in South Africa). Pinus greggii is also introduced in Italy, India, Nepal and Argentina.
|Wikispecies has information related to: Pinus greggii|
|Wikimedia Commons has media related to Pinus greggii.|
- in Candolle, Prodr. 16 (2): 396 (1868); distribution: Mexico, Sierra Madre Oriental – as given in Farjon 2001, p. 179
- in Sida 18 (4): 1092 (1999); distr: Mexico, San Luis Potosi, Querétaro, Hidalgo, Puebla – as given in Farjon 2001, p. 179
- distr: Mexico, Coahuila, Nuevo León – given with no further ref. in Farjon 2001, p. 179
- Farjon 1984, p. 83 says: small tree 15m.; Farjon&Styles 1997, p. 193 say: small to medium (height to 20 – 25m)
- Farjon 1984, p. 83
- Farjon&Styles 1997, p. 193
- Farjon 1984, p. 83; Farjon&Styles 1997, p. 193 say: reddish brown to grey-brown
- Farjon&Styles 1997, p. 193; Farjon 1984, p. 83 says: 8 – 15 cm long, yellowish-green and thin
- Farjon&Styles 1997, p. 193; Farjon 1984, p. 83 says: 8 – 15 cm long
- Dvorak 2003, p. 616
- Shaw 1914, p. 86
- Dvorak 2003, p. 615
- Farjon&Styles 1997, p. 193; Farjon 1984, p. 83 says: between 1500 and 2700 m
- van Wyk 2002, p. 144
- den Ouden & Boom 1965 do not have information on Pinus greggii
- Dvorak, W. S. - Pinus greggii. In: Vozzo, J.A. - Tropical Tree Seed Manual. United States Department of Agriculture; Forest Service. 2003. p. 615 – 617. online available as pdf
- Farjon, Aljos – Pines; drawings and descriptions of the genus Pinus. Publ. Brill / Backhuys, Leiden 1984
- Farjon, Aljos & Brian T. Styles – Pinus (Pinaceae). Monograph 75 of Flora Neotropica. New York Botanical Garden, New York 1997
- Farjon, Aljos – World checklist and bibliography of Conifers. 2nd ed. Royal Botanic Gardens, Kew 2001
- den Ouden, P. & Dr. B.K. Boom – Manual of Cultivated Conifers, ed. Martinus Nijhoff, The Hague 1965
- Shaw, George Russell – The genus Pinus. Cambridge 1914. online in gutenberg.org. With beautiful drawing.
- van Wyk, G. - Pinus greggii. In: Pines of Silvicultural Importance - Compiled from the Forestry Compendium, CAB International. Edition: illustrated. Published by CABI, 2002. ISBN 0-85199-539-X, ISBN 978-0-85199-539-7, p. 144f. Online available at Google Books
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