Life History and Disturbance Response of Populus tremuloides (quaking aspen)
Family: Salicaceae
Guild: pioneer, moist-site intolerant
Functional Lifeform: medium-size to large deciduous tree
Ecological Role: an aggressive pioneer on a wide range of sites from moist uplands to dry ridges and slopes; pure stands are maintained by frequent disturbance (usually fire); often a transient type, replaced by longer-lived or more shade-tolerant species
Lifespan, yrs (typical/max): 70/125
Shade Tolerance: very intolerant
Height, m: 15-26
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 5/20/70
Mast Frequency, yrs: 4-5
New Cohorts Source: seeds or sprouts
Flowering Dates: early spring
Flowers/Cones Damaged by Frost: no
Seedfall Begins: late spring
Seed Banking: seasonal, < 1 month
Cold Stratification Required: no
Seed Type/Dispersal Distance/Agent: plumed/ >200 m/ wind
Season of Germination: spring
Seedling Rooting System: variable
Sprouting: root suckers and stump sprouts common
Establishment Seedbed Preferences:
Substrate: mineral soil
Light: open areas only
Moisture: moist/wet required
Temperature: neutral
Disturbance response:
Fire: Quaking aspen is well-adapted to fire. Even where quaking aspen was a minor component of the prefire vegetation, it often dominates a site after fire. Quaking aspen populations decrease when fire is suppressed. Overstory removal and soil heating stimulate quaking aspen root sprouting. Fire creates a suitable mineral seedbed and reduces competition. Low-intensity surface fires probably occurred at short intervals in the past (every decade or so) but moderate-intensity fires occurred at intervals of several decades. Thin-barked and easily topkilled, aspen sprouts prolifically from adventitious buds in the root crown or from root suckers. Aspens <15 cm d.b.h. are susceptible to topkill from low-intensity surface fires. Moderate-intensity fires topkill most trees. Larger trees may survive but are susceptible to decay organisms from basal wounds. Seedling establishment may occur from seeds of surviving trees onsite or from offsite seeds carried by wind. Prescribed fire is usually most successfully executed in spring or early summer (and sometimes in the autumn) when the surface litter is dead and cured and the weather is dry.
Weather: New leaves and shoots are susceptible to early spring frosts. It is subject to windthrow, especially when trees have asymmetric crowns. It is subject to defoliation from hail, and hail may bruise or kill young trees. Vigor is reduced by drought. Quaking aspen is resistant to ice storm damage.
Air pollution: It is sensitive to ozone and sulphur dioxide and intermediate in sensitivity to hydrogen fluoride. Seedlings exhibited reduced biomass accumulation under controlled fumigation with ozone. A variable response to fumigation among clones was observed.