PLS 147 Lecture Notes - Lecture 19: Salicaceae, Biome, Chlorophyll
montane meadow at wetter ends, in lower, upper montane, subalpine,
aspen: local wet microsites at high elevations w/n (montane meadow)
Quaking aspen, Trembling aspen (Populus tremuloides)
● drainages and moist slopes
● >1700m
● associated w/ disturbance but may or may not require
● only BROADLEAF canopy species
● flattened petiole
○ when wind blows, it doesn't bend but instead buckles -- trembling/quaking
■ slough off snow
● Broadly but patchily distributed
● mainly on the East side of the Sierras
○ despite climate model, mainly absent from the west side
○ curious bc we tend to think east side is drier than west side
○ possibly bc more summer rainfall on east side than similar sites on western sides
○ geology of sierras creates more seeps and drainages (wet topography spots that
aspen likes) on the east
● Deciduous in a coniferous biome
○ it's hard to be deciduous
■ the shorter the summer, the harder it is to 'catch up' with evergreen
conifers
■ trees are evergreen bc dont want to forfeit leaves (photosynthetic parts)
○ adaptation: photosynthetic bark
■ relative of cottonwoods and willows (Salicaceae)
■ can photosynthesize in the winter so don't need to rely on leaves in the
winter
■ up to 40% of photosynthesis, even in leaf!
■ chlorophyll layer underneath
■ outside bark layer has lenticels: pores for gas exchange into the bark
●bring in CO2 to photosynthesize, O2 to respire
● lenticels are also found in wetlands
○ inundation. need oxygen for roots
● highly clonal
○ connected roots underground/ shared root system
○ one of the most clonal woody plants
○ Pando (latin for "i spread"), "The trembling Giant"
■ 107 acres of the same organism found in Utah
■ male clonal stand, dying? or at least shrinking
● reproduce sexually
○ catkins: genetically diverse seeds
○ but seedlings are rare
○ usually little aspens are actually connected underground
Document Summary
Montane meadow at wetter ends, in lower, upper montane, subalpine, aspen: local wet microsites at high elevations w/n (montane meadow) Associated w/ disturbance but may or may not require. When wind blows, it doesn"t bend but instead buckles -- trembling/quaking. Mainly on the east side of the sierras. Despite climate model, mainly absent from the west side. Curious bc we tend to think east side is drier than west side. Possibly bc more summer rainfall on east side than similar sites on western sides. Geology of sierras creates more seeps and drainages (wet topography spots that aspen likes) on the east. The shorter the summer, the harder it is to "catch up" with evergreen conifers. Trees are evergreen bc dont want to forfeit leaves (photosynthetic parts) Can photosynthesize in the winter so don"t need to rely on leaves in the winter. Up to 40% of photosynthesis, even in leaf!
