Life History & Disturbance Response of Ulmus sp. elm

Family: Ulmaceae
Guild: pioneer, spring-dispersed, moist-site, shade tolerant
Functional Lifeform: variable: small to large deciduous trees
Ecological Role: common subcanopy components of many wet-mesic forest types; also may occur on upland sites, but usually as occasional trees
Lifespan, yrs (typical/max): varies with species; 125-200/300
Shade Tolerance: intermediate to tolerant
Height, m: 12-38, depending on species
Canopy Tree: yes
Pollination Agent: wind
Seeding, yrs (begins/optimal/declines): 15/40/125
Mast Frequency, yrs: 1-4, varies with species
New Cohorts Source: seeds or sprouts
Flowering Dates: early spring
Flowers/Cones Damaged by Frost: yes
Seedfall Begins: late spring
Seed Banking: seasonal, up to 1 yr
Cold Stratification Required: no
Seed Type/Dispersal Distance/Agent: winged/ to 200m/ wind, water, birds
Season of Germination: spring
Seedling Rooting System: variable
Sprouting: stump sprouts and root suckers common
Establishment Seedbed Preferences
Substrate: mineral soil or variable
Light: variable, open or shaded
Moisture: moist required
Temperature: neutral
Disturbance response:
Fire: Fire rarely occurs in the moist areas where elms typically grow. When fire does occur and conditions are dry, elm greatly decreases following fire. Small topkilled trees sprout from the root crown or from root suckers. Wind- and water-dispersed seed are important in the establishment of elm following fire.
Exotics: The dominance of all North American elm species has been significantly decreased by Dutch elm disease, an exotic wilt fungus (Ceratocystis ulmi) which was introduced from Europe in 1930. It is spread by two species of elm bark beetles, one European (Scolytus multistriatus) and the other native (Hylurgopinus rufipes). American elms are the most susceptible of all the elms. Juvenile trees have some resistance to the disease, and elms produce wind-borne seeds before they die. Elms will likely persist in the forest as an understory species.