Life History and Disturbance Response of Ilex opaca (American holly)
Family: Aquifoliaceae
Guild: persistent, slow-growing understory tolerant
Functional Lifeform: small evergreen tree
Ecological Role: grows best on moist, slightly acid well-drained sites, but survives on sandy coastal soils or gravelly inland sites
Lifespan, yrs (typical/max): 100/150
Shade Tolerance: very tolerant
Height, m: 9-15
Canopy Tree: no
Pollination Agent: insects
Seeding, yrs (begins/optimal/declines): 5/20/100
Mast Frequency, yrs: 1
New Cohorts Source: seeds or sprouts
Flowering Dates: late spring
Flowers/Cones Damaged by Frost: yes
Seedfall Begins: fruit ripens by late fall, remains on tree until spring
Seed Banking: 1 yr +
Cold Stratification Required: yes
Seed Type/Dispersal Distance/Agent: drupe/ variable/ gravity, birds, other animals
Season of Germination: spring
Seedling Rooting System: taproot with many laterals
Sprouting: common on young stems
Establishment Seedbed Preferences
Substrate: variable
Light: overstory shade
Moisture: moist required
Temperature: neutral
Disturbance response:
Fire: American holly increases when fire is suppressed. Fire easily topkills American holly; its thin bark is easily injured by fire and the evergreen foliage is killed. Even large trees may be topkilled by low-intensity surface fires. American holly sprouts from the root crown, but short-interval fires (e.g., three annual) can nearly eliminate it from a stand. Seedling establishment may occur in the second or third year after fire from seeds of surviving trees onsite or from offsite seeds carried by birds and other animals. Prescribed fire has been used to eliminate seedlings and sprouts, particularly in pine stands.
Weather: American holly is intolerant of flooding in the growing season.
Air pollution: American holly is tolerant of ozone.