Great Basin montane forests

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Great Basin montane forests (WWF ecoregion NA0515)

Schulman Grove of Great Basin bristlecone pine (Pinus longaeva), Inyo Co., California

Great Basin montane forests map
Source of bioregions data: Olson, D. M. and E. Dinerstein. The Global 200: Priority ecoregions for global conservation. (PDF file) Annals of the Missouri Botanical Garden 89:125-126.

Distinctiveness (1=highest,4=lowest): 3 (bioregionally outstanding)
This naturally fragmented area supports some species that occur only on one or a few peaks. The elevation gradients result in high local diverslty.*

Conservation Status (1=most endangered, 5=most intact): 3 (vulnerable)
25 to 50% of this region remains intact. Fire suppression and grazing have changed species composition and allowed exotic plant species to invade.*

Characteristic species*

Juniperus spp., e.g.

Juniperus osteosperma

(juniper)

Pseudotsuga menziesii

(Douglas fir)

Abies concolor (white fir)

Pinus flexilis (limber pine)

Pinus longaeva (Great Basin bristlecone pine)

Pinus albicaulis (white bark pine)

Tsuga mertensiana

(mountain hemlock)

Pinus contorta

(lodgepole pine)

Populus tremuloides

(quaking aspen)

Associated habitats

Schulman Grove, Inyo National Forest, White Mountains, California

(left) Great Basin bristlecone pines (Pinus longaeva) have a relatively normal size and morphology on the relatively moist north-facing slopes. (2nd from left) However, on the drier south-facing slopes smaller, stunted trees may actually be centuries older. (center two images) Under drought conditions trees may die back and maintain a smaller growing surfaces. (2nd from right) At the lower elevations, trees face near-desert conditions and have severely restricted growth, (right) Even after dying, dead trunks may remain standing for hundreds of years. This image shows the high Sierras to the west which remove most of the moisture from the air that moves over them. (c) 2011 Steven J. Baskauf hires hires hires hires hires hires

Cross sections of bristlecone pine (Pinus longaeva) trunks, Left: When a bristlecone loses part of its crown, it responds by allowing part of the trunk to die while maintaining a narrow strip of living bark. This "slab growth" can be seen in this cross section. The narrow, light colored crescent on the right edge was the only part of the trunk with living bark. Right: Cross section of about 3000 years of growth rings. The oldest living Great Basin bristlecone is 4600 years old and still growing in the Schulman Grove in the White Mountains. (c) 2005 Steven J. Baskauf hires hires

* Ricketts, T.H., E. Dinerstein, D.M. Olson, C.J. Loucks, et al. (1999) Terrestrial Ecoregions of North America: A Conservation Assessment. World Wildlife Fund - United States and Canada. Island Press, Washington, D.C. pp. 248-250.