Life History and Disturbance Response of Quercus alba (white oak)
Family: Fagaceae
Guild: persistent, large-seeded, advance growth
dependent
Functional Lifeform: large deciduous tree
Ecological Role: common upland oak found in mixed
forests on dry ridge tops, upper slopes and rich coves; persists for long
periods, but shade tolerance declines as trees grow large; responds well
to release
Lifespan, yrs (typical/max): 300/600
Shade Tolerance: intermediate
Height, m: 24-30
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 20/75/200
Mast Frequency, yrs: 4-10
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: no
Seed Type/Dispersal Distance/Agent: nut (acorn)/
to 50 m/ gravity, birds, other animals
Season of Germination: fall
Seedling Rooting System: taproot
Sprouting: seedling and stump sprouts common
Establishment Seedbed Preferences:
Substrate: loose soil or humus, with litter cover
Light: overstory shade
Moisture: neutral
Temperature: 10 - 16C favors germination
Disturbance response:
Fire: White oak is well-adapted to periodic fire.
It is unable to regenerate beneath the shade of parent trees and relies
on periodic fires for its perpetuation. Fire exclusion has inhibited white
oak regeneration through much of its range. Periodic fires in upland oak
systems promote oak dominance by opening the canopy and reducing competition.
Fires in upland forests tend to be low- to moderate-intensity and short
in duration. Fires primarily occur during the dormant season at frequent
intervals (once or more per decade to several decades). White oak is moderately
resistant to fire, possessing thick, rough, scaly bark and deep roots.
It becomes more fire resistant with age as bark thickens. When topkilled,
seedlings and saplings readily and persistently sprout from the root crown
or stump. Small fire scars are rapidly compartmentalized and damage is
usually limited. Fire promotes seedling establishment by creating favorable
seedbeds and reducing competition. However, acorns present during the fire
are usually killed. Seedling establishment may occur from seeds of surviving
trees onsite or from offsite seeds carried by birds and other animals.
Low-intensity prescribed fire has been used successfully to promote white
oak advanced regeneration.
Weather: White oak is moderately resistant to ice
breakage, but sensitive to flooding.
Air pollution: White oak is intermediate in sensitivity
to sulphur dioxide and sensitive to ozone. Variable foliar injury has been
observed under high ambient ozone conditions; no injury was noted under
controlled fumigations.
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.