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Life History and Disturbance Response

In this section, we present life history information about each species. Sources are many, and are listed at the end of this section. The intention is to provide concise, synthesized information about many, but not all, ecological aspects of the species. We cannot, and do not, intend to present exhaustive information for each species, but rather a ‘broad brush’ approach so that comparative and categorical analyses can be performed. We refer you to the Silvics of North America manuals (Burns and Honkala 1990a,b) for more detailed information on damaging agents as well as extensive text and citations on many of the variables listed below. We also refer you to the USDA Forest Service Fire Effects Information System data base (Fischer, ongoing) which contains a large array of basic as well as fire-related information about nearly all tree species in the United States, and to the many data bases being brought online through the National Biological Information Infrastructure (U.S. Geological Survey, ongoing).

Data presented for each species are:

Family: botanical family of the species.
Guild: grouping of species according to tree regeneration capabilities.
Functional Lifeform: relates to structural size, form, and seasonal nature of tree species.
Ecological Role: short explanation of habitat for the species.
Lifespan, yrs (typical/max): longevity under typical or ideal conditions.
Shade Tolerance: capacity to survive and grow in the understory [very tolerant, tolerant, intermediate, intolerant, or very intolerant].
Height, m: typical heights achieved under forested conditions.
Canopy tree: species usually occupies a position in the main crown canopy [yes, no (understory tree)].
Pollination Agent: major vector of pollination [wind, insects].
Seeding, yrs (begins/optimal/declines): age when the species, under good conditions, starts to produce viable seeds, reaches its optimum, and begins to decline in seed production.
Mast Frequency, yrs: frequency of good seed years (large seed crops).
New Cohorts Source: possible sources of new plants [seeds, sprouts (seedling sprouts or stump sprouts), root suckers].
Flowering Dates: season of flowering [early spring (~March 1-April 15), late spring (April 15-May 31), or summer (June-August)].
Flowers/Cones Damaged by Frost: flowers or cones can be damaged by frost [yes, no].
Seedfall Begins: time when ripe seed starts to be dispersed [spring-summer, early fall (September-October), or late fall-winter (November-February)].
Seed Banking: time that seed can survive in the seed bank [seasonal, < 1 month; seasonal, up to 1 year; short-term persistent, 1-10 years; persistent, 10+ years].
Cold Stratification Required: does the seed need cold stratification before it can germinate [yes, no].
Seed Type/Dispersal Distance/Agent: type of seed (or fruit), its typical dispersal distance, and common dispersal agent(s) [nuts and pods, to 50 m, gravity and animals; small nonwinged, to 50 m, wind and gravity; berries and drupes, to 100 m, birds and gravity; winged seeds, to 100 m, wind; winged seeds, 100-200 m, wind; plumed seeds, > 200 m, wind].
Season of Germination: season when seeds typically germinate [spring, summer, fall].
Seedling Rooting System: form of seedling/juvenile root system [taproot; variable (depends on soil type and moisture levels); shallow-spreading].
Sprouting: possible modes of vegetative reproduction [seedling sprouts, stump sprouts, root suckers, stem/rhizome sprouts, layerings].
Establishment Seedbed Preferences:
Soil: substrate needed to germinate [bare mineral soil; litter/humus/moss; or variable].
Light: seedbed light environment suitable for germination [open conditions only — high light levels; overstory shade — variable light levels]. For some species, the seeds can germinate, even germinate better, under shade, but are intolerant of shade to survive and grow. As such, the species may be listed as intolerant to shade, yet prefer shade for germination (for example, Betula papyrifera, Fraxinus nigra, Quercus nigra, Pinus taeda).
Moisture: moisture level that supports germination and establishment [wet required, moist required, moisture neutral].
Temperature: soil temperature required for germination [cool/cold soil required, warm soil required, temperature neutral].
Disturbance Response: effects of fire, air pollution, drought, insects and disease on the species. This text focuses primarily on nonbiological disturbance agents (fire, weather, and to the extent available, air pollution), but also considers some particularly devastating (mostly exotic) pests and disease. Special attention has been given to response to fire, as this type of synopsis has not previously been published for Eastern species.