Life History and Disturbance Response of Quercus macrocarpa (bur oak)
Family: Fagaceae
Guild: persistent, large-seeded, advance growth dependent
Functional Lifeform: large deciduous tree
Ecological Role: found on a wide range of sites from dry uplands and sandy plains to bottomlands and moist flats; very drought resistant
Lifespan, yrs (typical/max): 200/400
Shade Tolerance: intermediate
Height, m: 24-30
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 35/75/150
Mast Frequency, yrs: 2-3
New Cohorts Source: seeds or sprouts
Flowering Dates: late spring
Flowers/Cones Damaged by Frost: Information Not Found
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: variable (without litter cover)
Light: overstory shade
Moisture: moist required
Temperature: neutral
Disturbance response:
Fire: Periodic fire favors bur oak communities. When fire is suppressed, seedlings of bur oak are unable to compete with other, more shade-tolerant species, and bur oak communities may be replaced by more shade-tolerant maple-basswood (Acer spp.-Tilia spp.) forests. Large bur oak trees have a thick, fire-resistant bark. Small grass fires are relatively common in some bur oak savannas, and typically topkill only young trees. Seedlings to large saplings sprout vigorously from the root crown or rhizomes when burned, but larger trees sprout often less vigorously. Seedling establishment may occur from seeds of surviving trees onsite or from offsite seeds carried by birds and other animals. Prescribed fire has been used to prevent bur oak invasion to prairies. Annual burning for prairie maintenance can prevent bur oak from increasing. On other sites, an interval of up to 10 years between fires may be necessary to allow for the build-up of sufficient fuels for fire to reduce oak trees to shrubs and eliminate tree seedlings.
Weather: Bur oak is extremely resistant to drought and intolerant of flooding.
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.