Sierra de la Laguna pine-oak forests
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The Sierra de la Laguna pine-oak forests is a subtropical coniferous forest ecoregion, found in the Sierra de la Laguna at the southern tip of the Baja California Peninsula of Mexico. The pine-oak forests are found above 800 meters elevation, and are surrounded at lower elevations by the Sierra de la Laguna dry forests. The ecoregion encompasses an area of 1100 km² (400 square miles). The pine-oak forests have a unique and diverse flora and fauna, including 694 plant species, of which approximately 85 percent are endemic.
The higher elevation gives the ecoregion a subtropical to temperate climate, in contrast to the dry tropical climate of the lowlands. Rainfall is higher than the lower-elevation dry forests and deserts of the peninsula, averaging 760 mm annually. Rain falls mostly in the summer, with occasional winter rains. The composition of the pine-oak forests varies with elevation; oak woodlands predominate from 800 to 1200 meters elevation, with oak-pine woodlands between 1200 and 1600 meters elevation, transitioning to pine-oak forests above 1600 meters elevation. Mosses and lichens are abundant throughout.
The oak woodlands from 800 to 1200 meters elevation are warmer and drier, with evergreen oaks predominant (principally Quercus devia; Q. arizonica and Q. rugosa have a limited distribution), along with lower trees and shrubs such as Dodonaea viscosa, Bumelia peninsularis, and Buddleia crotonoides.
Above 1200 meters elevation, the oak woodlands transition to oak-pine forests. The only pine present is an endemic subspecies of Mexican Pinyon, Pinus cembroides subsp. lagunae, mixed with oaks, including Quercus devia and Q. tuberculata, and other broadleaf trees, including Arbutus peninsularis and Nolina beldingi. Lower trees and understorey shrubs include Calliandra peninsularis, Mimosa xanti, Heterotoma aurita, Verbesina pustulata and Hypericum peninsulare. Above 1600 meters elevation, pine predominates, mixed with oaks, and with an understory of grasses (Muhlenbergia spp. and Festuca spp.).
