Life History and Disturbance Response of Quercus nigra (water oak)
Family: Fagaceae
Guild: persistent, large-seeded, advance growth dependent
Functional Lifeform: medium-size to large deciduous or semievergreen tree
Ecological Role: grows on bottomlands and moist, well-drained uplands; moderately tolerant of seasonal flooding; colonizes old fields and invades pine forests; usually a transitional species on moist/wet hardwood sites
Lifespan, yrs (typical/max): 175/Information Not Found
Shade Tolerance: intolerant
Height, m: 15-32
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 20/Information Not Found
Mast Frequency, yrs: 2
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: yes
Seed Type/Dispersal Distance/Agent: nut (acorn)/ to 50 m/ gravity, birds, other animals
Season of Germination: spring
Seedling Rooting System: taproot
Sprouting: stump sprouts common
Establishment Seedbed Preferences:
Substrate: variable
Light: overstory shade
Moisture: moist/wet required
Temperature: neutral
Disturbance response:
Fire: Apparent from its common name, water oak grows on bottomland sites and moist uplands where fire rarely occurs. Water oak litter and other fuel along riparian corridors are often moist and burn poorly. Short-interval low-intensity fires in both the dormant and growing season reduce the number of water oak saplings. Root systems are weakened and eventually killed by burning during the growing season. Water oak is extirpated from upslope forests by short-interval growing-season fires. A thin-barked species, it is susceptible to damage and topkilling from fire. Low-intensity surface fires topkill water oak less than about 8-10 cm d.b.h. The bark of larger trees is thick enough to protect the cambium from low-intensity fires and the buds are above the heat of the fire. Fire-caused wounds can be entry points for aggressive, damaging fungi. Water oaks sprout from adventitious buds in the root crown or from root suckers, more often in younger trees (seedlings and saplings) than older trees. 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 water 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: Water oak is susceptible to permanent standing water.
Air pollution: Water oak is sensitive to sulphur dioxide.
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.