PLS 147 Lecture Notes - Lecture 18: Abies Magnifica, Arctostaphylos, Pinus Balfouriana
Mostly coniferous at higher elevations
jeffrey pine, red fir, aspen, montane meadow, lodgepole pine, subalpine woodland
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Why conifers at high elevations?
● rare non-conifer
○ deciduous
○ broad-leaved
○ branches going up
○ white bark
Adaptations to snow-loading
● needle leaves
● tree geometry
○ sloping downward
● soft wood
Why evergreen?
● probably short growing season
● minimize yearly 'start-up costs'
● aspen are deciduous, but that has its own problems
most conifers are in places that are snowy and have short growing seasons
temperature and % snow are important factors in characterizing lower montane, upper montane,
and subalpine communities
Upper Montane communities
Red Fir (Abies magnifica)
● often mono-dominant
○ where as lower montane can have dominant but always a mix of species
● Herb layer
○ woody
○ has some shrubs but very short
● little shrub or sub-canopy
● deep snowpack, rarely burns
● up to 70m tall, 230'
● up to 10' diameter (3m)
● 6000-9500 ft elevation
● live ~300 years
● snowflake branching pattern
● seedlings can tolerate much more snowpack than white fir
○ red rolls, white won't
Document Summary
Mostly coniferous at higher elevations jeffrey pine, red fir, aspen, montane meadow, lodgepole pine, subalpine woodland. Aspen are deciduous, but that has its own problems most conifers are in places that are snowy and have short growing seasons temperature and % snow are important factors in characterizing lower montane, upper montane, and subalpine communities. Where as lower montane can have dominant but always a mix of species. Seedlings can tolerate much more snowpack than white fir. White fir may be a better competitor though (grow faster, tolerate more drought) Often a relatively poor ground layer, with bare ground (needle, woody litter) Pinemat manzanita (arctostaphylos nevadensis) (also in chaparral) Red fir intergrades with western white pine and jeffrey pine on drier slopes. Most stands on the east side of the sierras. West side stands are mixed and heterogenous on higher, exposed rocky slopes with shallow soils. Ponderosa more common on western side of sierras.
