Limber pine

Limber pine (Pf) - Pinus flexilis

Page Index

Geographic Range & Ecological Amplitudes

Description
Limber pine is a small- to medium-sized (<15 m tall), slow-growing, long-lived conifer of high mountains. When mature, it may develop multi-stemmed growth form, with typically stubby branches, an upswept branched crown, and rough, dark brown bark with wide scaly plates. It is not a timber crop species, but it is valued for watershed protection and aesthetics.
Geographic Range  Geographic element:
Western North American/Cordilleran and marginally Pacific

Distribution in Western North America:
(south) in the Pacific region; central and south in the Cordilleran region
Ecological Amplitudes 


limber pine
Climatic amplitude:

subalpine boreal - (cool temperate) 

Orographic amplitude:
(montane) - subalpine

Occurrence in biogeoclimatic zones:
upper southeastern ESSF, (upper southeastern MS)


Edaphic Amplitude

Range of soil moisture regimes:
very dry - moderately dry - slightly dry - fresh - moist - (very moist)

Range of soil nutrient regimes:
poor - medium - rich - (very rich); calciphytic

Limber pine grows mostly on calcareous substrates; therefore, Krajina (1969) concluded that limber pine requires for productive growth higher amounts of calcium and magnesium than whitebark pine, jack pine, and lodgepole pine.

Tolerances and Damaging Agents

 
Root System Characteristics Similar to whitebark pine, limber pine develops a deep and spreading root system. It is well anchored, even on rocky substrates and is seldom uprooted despite its large, exposed crown. Roots of limber pine are associated with both ecto- and endo-mycorrhizae.
Tolerances
tolerance to tolerance class comments
low light L most commonly grows in open canopy forests
frost H often forms in the upper timberline
heat M tolerates insolated sites
water deficit H frequent on water-deficient sites
water surplus L absent on waterlogged sites
nutrient (mainly N) deficiency M absent in very poor, acid soils
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Damaging Agents
damaging agent resistance class comments
snow H resistant but not resilient to high snowpack
wind H deeply rooted and well anchored
  risk class  
fire H especially in young stands
insect L not a serious concern in subalpine forests; mountain pine beetle
fungi L not a serious concern in subalpine forests; root and butt rots (e.g., red ring rot, Armillaria root disease, Schweinitzii butt rot), white pine blister rust
other agents L not a serious concern in subalpine forests; dwarf mistletoes (Arceuthobium spp.)
Associated tree species and successional role In British Columbia, limber pine grows in both pure and mixed-species stands. With increasing elevation, the species grows in isolated clumps on exposed ridges. It is a pioneer species (primary succession) and may be present in early, mid-, and late stages of secondary succession; a variable component in the upper ESSF forest. Except on most severe sites, where trees remain widely spaced, limber pine show little evidence of maintaining its population in the presence of other conifers.
 
associated 
tree species
occurance class major area of occurance
whitebark pine L upper, southeastern ESSF
engelmann spruce L upper, southeastern ESSF
subalpine fir L upper, southeastern ESSF

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Silvical Characteristics

 
characteristic interpretive class comments
reproduction capacity H large seed crops are produced every 2-4 years
seed dissemination capacity H dispersion essentially by rodents and Clarks nutcracker
potential for natural regeneration in low light L practically nil; a shade-intolerant and exposure-requiring species
potential for natural regeneration in the open H providing favourable environmental conditions for germination
response of advance regeneration to release na advance regeneration does not develop in the absence of adequate light and seedbeds
self-pruning capacity in dense stands L dense stands are very infrequent
crown spatial requirements H forms wide irregular crowns
light conditions beneath closed-canopy, mature stands na closed-canopy stands are very infrequent
potential productivity na non-crop species; site index functions are not available
longevity H the maximum reported age: 1,650 years in central Idaho

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Genetics and Notes

Genetics Genetic variation exists within limber pine in a general north-south pattern, but range of variability for any one trait is small.
Notes Steele, R. 1990. Pinus flexilis. Pp. 348-354 in R.M. Burns and B.H. Honkala (technical coordinators) Silvics of North America, Vol. 1. Agri. Handbook 654, USDA For. Serv., Washington, D.C.

Limber pines greatest values are for wildlife habitat, watershed protection, and aesthetics. More detailed silvics information is given by:
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