Life History and Disturbance Response of Populus grandidentata (bigtooth aspen)
Family: Salicaceae
Guild: pioneer, moist-site intolerant
Functional Lifeform: medium-size deciduous tree
Ecological Role: found on a wide range of sites but grows best on moist, fertile sandy uplands; vigorous root suckers develop on disturbed sites
Lifespan, yrs (typical/max): 60/100
Shade Tolerance: very intolerant
Height, m: 18-24
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 20/50/70
Mast Frequency, yrs: 4-5
New Cohorts Source: sprouts, seedlings (rare)
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, water
Season of Germination: spring
Seedling Rooting System: variable
Sprouting: stump sprouts and root suckers common
Establishment Seedbed Preferences:
Substrate: mineral soil
Light: open areas only
Moisture: moist/wet required
Temperature: neutral
Disturbance response:
Fire: Bigtooth aspen populations increase after fire, and decrease when fire is suppressed. Although individual trees are susceptible to topkill, overstory removal and soil heating stimulate aspen root sprouting. Fire also creates a suitable mineral seedbed and reduces competition. Stand-replacing fires are high intensity surface fires, at intervals of several decades, most often occurring in the autumn when fuels are dry and leaf litter is deep. Low-intensity surface fires also occur. A thin-barked species, bigtooth aspen is very susceptible to fire injury and topkill, and even low-intensity fires kill seedlings and saplings. If large trees survive fire but are wounded, they often die of disease. Seedling establishment may occur from seeds of surviving trees onsite or from offsite seeds carried by wind. Prescribed fire is used as a management tool to regenerate bigtooth aspen stands. To maximize the number of suckers, moderate-intensity fires function to kill remaining canopy stems and remove duff following harvest. Low-intensity fires do not always induce sufficiently dense and vigorous suckers to regenerate a stand.
Weather: Bigtooth aspen is windfirm and resistant to ice and snow damage.
Air pollution: Bigtooth aspen is sensitive to sulphur dioxide. No observed difference in the height of seedlings fumigated with ozone under controlled conditions has been noted. Variable response to fumigation among clones has been observed.