Life History & Disturbance Response of Quercus phellos willow oak

Family: Fagaceae
Guild: persistent, large-seeded, advance growth dependent
Functional Lifeform: large deciduous tree
Ecological Role: grows on bottomlands and moist, alluvial soils; moderately tolerant of seasonal flooding; grows in mixtures with other wet/mesic hardwoods; responds well to release; produces abundant acorn crops that benefit wildlife
Lifespan, yrs (typical/max): 200/Information Not Found
Shade Tolerance: intolerant
Height, m: 24-37
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 20/Information Not Found
Mast Frequency, yrs: 1
New Cohorts Source: seeds or sprouts
Flowering Dates: late spring
Flowers/Cones Damaged by Frost: yes
Seedfall Begins: early fall
Seed Banking: up to 1 yr
Cold Stratification Required: yes
Seed Type/Dispersal Distance/Agent: nut (acorn)/ to 50 m/ gravity, birds, other animals
Season of Germination: spring
Seedling Rooting System: taproot
Sprouting: seedling and stump sprouts common
Establishment Seedbed Preferences
Substrate: variable, with litter cover
Light: overstory shade
Moisture: moist required
Temperature: neutral
Disturbance response:
Fire: Willow oak grows on bottomland sites where fire rarely occurs. Willow oak litter and other fuel along riparian corridors are often moist and burn poorly. A thin-barked species, it is susceptible to damage and topkilling from fire. Low-intensity surface fires topkill seedlings and saplings; larger trees with thicker bark have more resistance. It is more susceptible to growing-season fires than dormant-season fires. Fire-caused wounds can be entry points for insects and aggressive, damaging fungi. Willow oaks sprout from adventitious buds in the root crown or from root suckers, more often in younger trees (seedlings and saplings) than older trees. Short-interval low-intensity fires in both the dormant and growing season reduce the number of saplings. Root systems are weakened and eventually killed by burning during the growing season. Seedling establishment may occur from seeds of surviving trees onsite or from offsite seeds carried by birds and other animals. Prescribed burning has been used to control willow oak where it is not desired but fires are very difficult to ignite in the moist bottomlands where it typically grows. The most effective prescribed burning is done between late spring and early winter.
Weather: Roots are inhibited by soil saturation during the growing season, and permanent standing water will kill willow oak.
Air pollution: There was no observed change in height and biomass accumulation in seedlings fumigated with ozone under controlled conditions.
Exotics: Gypsy moth (Lymantria dispar) is a defoliator of eastern hardwood forests, introduced to Massachusetts from France in 1885. It has spread throughout New England into Virginia and Michigan. Defoliation causes growth loss, decline, and mortality. It feeds on many tree species, but Quercus and Populus are the most susceptible taxa, and trees growing on xeric sites are the most vulnerable. Various efforts have been made to control it, with mixed results. A fungus, Entomophaga maimaiga introduced from Japan causes considerable mortality to gypsy moth populations. E. maimaiga levels are promoted by damp weather.