SITE CONDITIONS
Stands of high elevation white pines are typically found on exposed, dry, and rocky slopes, ridges, and mountain peaks. They are well adapted to survive in the inhospitable environmental conditions that exist in these locations including intense cold, drought, wind, and blowing snow and ice.
At higher elevations, stands of white pines transition from upright trees in forests to sparse patches of shorter trees distributed among the alpine flora. At the highest elevations, some of white pines are sculpted and deformed by the elements into a shrub - like form called a krummholz.
Soils, climate (e.g. depth and duration of snowpack), and disturbances (e.g. fire, insects and diseases, grazing, and human) all influence the continued survival of the pines on a site.
For species specific site conditions, click on the species of interest below:
Rocky Mountain bristlecone pineGreat Basin bristlecone pine
Foxtail pine
Limber pine
Whitebark pine
Referred Literature: 22, 11, 31, 20
Rocky Mountain bristlecone pine (Pinus aristata)
Site
Rocky Mountain Bristlecone Pine is most commonly found on dry and steep slopes (20 - 35°) with south or west facing aspects.
A mean annual temperature of 1.5°C (35°F) and a growing season of less than 110 days were recorded for a Rocky Mountain bristlecone pine stands in New Mexico.
Precipitation can be extremely variable in the central Rocky Mountains. The annual precipitation of Rocky Mountain bristlecone sites has been recorded at as little as 410mm (16 inches) on Pike's Peak while other sites receive as much as 1,520mm (59.8 inches) in the San Juan range of Colorado.
Soils
Shallow - 5 - 10cm (2 to 4 inches) deep
Acidic - pHs ranging from 4.47 - 6.85
Cold - Mean soil temperature of 1°C (33°F)
Nutrient poor - Nitrogen and Phosphorus are in short supply
Parent materials - Granite and extrusive igneous derived soils were most common in Colorado
Referred Literature: 24, 25, 21, 26, 27, 28, 25, 29, 27
back to listGreat Basin bristlecone pine (Pinus longaeva)
Site
Great Basin bristlecone pine typically grows on very dry exposed slopes (10 - 50%) that are south and west facing.
The mean monthly temperature average was 10°C (50°F) in July and August and below freezing November through April at a site in the White Mountains of California.
Precipitation can be extremely variable across the range Great Basin bristlecone pine. In the White Mountains in California a mean precipitation of 300mm per year (12 inches/year) was reported whereas on a site in Nevada a mean precipitation of about 600mm per year (24 inches/year) was reported.
Soils
Shallow and Rocky
Parent Materials - Limestone or dolomite derived soils are most common with some sandstone and quartzite.
Dolomite soils occur in the White Mountains (CA). They are alkaline (high pH), high in calcium and magnesium and low in phosphorus. They stay cooler and retain more water because their light color than some other substrates.
Referred Literature: 30, 32, 31, 9, 19, 31,34,35,33
back to listFoxtail pine (Pinus balfouriana)
Site
Southern foxtail (ssp. austrina) is found on the drier, eastern side of the Sierra Nevada with moderate slopes less than 33%.
Northern foxtail (ssp. balfouriana) is found in small stands on ridge crests, mountain tops and steep, south and west facing slopes. One exception is when they are growing on serpentine soil where it tends to grow in large homogenous stands on slope ranging from 15 - 32%.
Climate
Southern foxtail climate tends to be cold in the winter and warm and dry in the summer. The annual precipitation ranges from 500 - 750mm (20 to 30 inches).
Northern foxtail climate is influenced by the Pacific Ocean with an annual precipitation is 1,250 - 1,750mm (49 - 60 inches).
Soils
Southern foxtail soils are generally well drained and derived from decomposed granite.
Northern foxtail can be found on gabbro, granodiorite, limestone, and schist derived soils.
Referred Literature: 36, 37, 38, 39, 2, 5, 41, 42, 43, 44, 124
back to listSite
Limber pine has the widest geographical distribution and elevational range of all the high elevation white pines. It can be found on a variety of site conditions throughout western North America. Generally, it is found on dry sites at mid - elevation to the upper treeline. At high elevations it has adapted to steep, rocky, and exposed ridges and summits.
Precipitation and temperatures can be extremely variable across the range Limber pine. Generally, it can be described as dry with the wettest months occurring during the growing season and temperatures that vary greatly throughout the season. Limber pine grows on sites with mean daily air temperature in July of 13 o C (55 o F) at upper treeline (forest to alpine transitions) and 23 o C (73 o F) at lower treeline (forest to grassland transition) in Colorado.
Parent materials - Occurs on soil derived from many types including limestone, sandstone, granite, serpentine, quartzite, shale, obsidian, pumice and calcareous substrates.
Well drained
Nutrient poor
Referred Literature: 42, 45, 46, 47, 48
back to listWhitebark pine (Pinus albicaulis)
Site
Whitebark Pine can be found on all exposures but is most commonly occupy south and west facing slopes on ridges and near timberline. The sites tend to be rocky and well drained.
Climate
Mean July temperatures range from 13 - 15°C (55 - 59°F). Mean January temperatures range from - 9 to - 5°C (15 - 23°F). The growing season last about 90 - 110 days.
The annual precipitation on Whitebark sites ranges from 600 - 1,600mm (24 to 63 inches) per year. Two thirds of the precipitation is received as snow or sleet, with rain prevailing June through September.
Soils
Shallow and rocky
Acidic - pH of 4.8 - 5.0 but may occur on basic soils
Poorly developed, well drained, and nutrient poor
Parent materials - derived from basalt or granite; occasionally occurs on sedimentary soils
Referred Literature: 49, 50, 51, 11, 53, 16, 55, 52, 56, 54
back to list