АҚШ және Мексиканың Сіерра-Мадре Оксиденталь қыраттарындағы қарағай-емен ормандары

Temperate broadleaf and mixed forests ecoregion of Mexico and the United States

The Sierra Madre Occidental pine–oak forests (lang es) are a Temperate broadleaf and mixed forests ecoregion of the Sierra Madre Occidental range from the southwest USA region to the western part of Mexico. They are home to a large number of endemic plants and important habitat for wildlife.

The Sierra Madre Occidental run north to south in western Mexico from the center of the country towards the United States border. The Sierra Madre Occidental is Mexico's largest range, and the ecoregion extends approximately 1,200 kilometers from southern Arizona to northern Jalisco. Pine forests occur from 1600 to 3200 meters elevation under a variety of conditions. The species vary with location and conditions. Arizona pine (Pinus arizonica), Apache pine (Pinus engelmannii), and Chihuahua pine (Pinus leiophylla var. chihuahuana) are common in the northern and central portions of the range. Pinus durangensis and Pinus teocote are found from the Sierra of central Chihuahua to the southern end of the range. Pinus lumholtzii and Pinus luzmariae are found on thin, rocky, and acidic soils. Pinus cooperi can form single species stands in mountain valleys with deep soils. Pinus oocarpa, Pinus pseudostrobus, Pinus douglasiana, Pinus herrerae, Pinus devoniana, and Pinus maximinoi are found in more humid areas on the western slope of the mountains. The many reptiles include the rock rattlesnake (Crotalus lepidus), twin spotted rattlesnake (Crotalus pricei), ridgenose rattlesnake (Crotalus willardi), and some spiny lizards (Sceloporus clarki, S. jarrovii, S. scalaris and S. virgatus). Finally, the mountains are an important stage in the migration route of monarch butterflies.

The pine forests have been cleared by the logging and paper industries since the 1800s and only a very small percentage of original forest remains. This removal of habitat has resulted in the presumed extinction of the imperial woodpecker, once the largest woodpecker on earth. The increase of global warming is expected to have some devastating effects on the pine trees located in the Sierra Madre Occidental. The predicted outcome of global warming in this subtropical region, is the reduction of plant/animal productivity and growth. Another effect would be that the increase of climate warming would also lead to tree mortality affecting not only the pine trees located in the Sierra Madre Occidental but also other pine trees in the surrounding areas.

13.5% of the ecoregion is in protected areas.