Life History and Disturbance Response of Fraxinus americana (white ash)
Family: Oleaceae
Guild: opportunistic, fast-growing understory tolerant
Functional Lifeform: large deciduous tree
Ecological Role: colonizes fertile old fields and large forest openings; grows best on moist, well-drained soils and is common in many mixed hardwood forest types; becomes less shade tolerant with age but persists as a subdominant and responds well to release
Lifespan, yrs (typical/max): 260/300
Shade Tolerance: intermediate
Height, m: 24-30
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 20/40/125
Mast Frequency, yrs: 3-5
New Cohorts Source: seeds or sprouts
Flowering Dates: late spring
Flowers/Cones Damaged by Frost: yes
Seedfall Begins: early fall
Seed Banking: 1 yr +
Cold Stratification Required: yes
Seed Type/Dispersal Distance/Agent: winged/ to 200 m/ wind
Season of Germination: spring
Seedling Rooting System: variable
Sprouting: seedling and stump sprouts common
Establishment Seedbed Preferences:
Substrate: variable
Light: overstory shade
Moisture: moist required
Temperature: neutral
Disturbance response:
Fire: White ash commonly grows on moist upland sites where fire is probably infrequent, occurring at intervals of several decades to centuries. Although white ash is highly susceptible to topkilling from fire, it readily sprouts from the root crown and may actually increase in density. Larger trees are moderately susceptible to fire-caused wounding and infestation by insects and decay organisms. After topkilling, it sprouts from the root crown or caudex. Seedling establishment may occur two years after the fire from seeds of surviving trees onsite or from offsite seeds carried by wind.
Weather: White ash has some tolerance to short-term flooding.
Air pollution: White ash is sensitive to ozone. Symptoms of foliar injury have been noted in areas of high ambient ozone. White ash seedlings exhibited reduced biomass accumulation under controlled fumigation with ozone.