Images © by James L. Reveal, Norton-Brown Herbarium, University of Maryland, unless otherwise credited.

BSCI 124 Lecture Notes

Department of Plant Biology, University of Maryland

LECTURE 39 - TERRESTRIAL BIOMES, Part 3
Temperate Rain, Sclerophyllous and Deciduous Forests

VI. General features of temperate deciduous forests

A. Introduction.
B. Origin.
C. Environment.
D. Biota.
E. Population structure.
F. Biological productivity.

VII. Temperate Rain Forest

A. Location: Pacific Coast from southern Alaska to central California.
B. Features: (see picture at this site)
- 1. Mostly coastal and in low mountains (less than 9,000 ft)
  2. Abundant precipitation, rain and snow; 25-160 in (65-400 cm).
  3. Cool temperatures, rarely below 5° F or above 100° F; moister and cooler in the north. Fog an important component.
  4. Soils are deep and rich but mineral poor.
  5. Fire can be significant albeit usually not devastating to larger trees.
  - a. Redwood - (see right).
    b. Douglas fir
  6. A fair diversity of plants and animals.
C. Vegetation:
- 1. Diversity of conifers and hardwoods, many tall and old. Pines, fir, spruce, redwood (Sequoia sempervirens) and Douglas fir. Old growth forest was common; now reduced to about 10% of original.
  2. Numerous species of shrubs and wild flowers. Many endemic.
D. Animals:
- 1. Numerous resident birds and animals.
  2. Some fur-bearing species (seal, otter) were common
E. History:
- 1. Ancient, relictual forest, many "living fossils" - plants whose ranges were once much more widely distributed.
  2. Many related plants also found in Southeast Asia.
  3. Position of forest not affected by Pleistocene glaciation
  4. Many species adapted to slow burning fires (see the bark of redwood to the right)
F. Exploitation:
- 1. Lumbering has dramatically reduced the extent of the forest; "clear-cutting" generally no longer practiced.
  2. Fire suppression in recent years has increased losses due to wild fire.

Sclerophyllous Forest in the Sierra Madre Occidental, Durango

VIII. Mixed Conifer and Hardwood Sclerophyllous Forests

A. Location: mountains of northern Mexico, and most notably that found in the Sierra Madre Occidental and Sierra Madre Oriental.
B. Features:
- 1. Warm seasonal rains, some snow; mostly 30-50 in (75-150 cm)
  2. Moderate temperatures, but freezing temperatures in arid alpine zones atop volcanic peaks in the "trans-volcanic belt"
C. Vegetation:
- 1. Mixture of numerous species of conifers and hardwoods
  2. Many hardwoods and large shrubs (to 30 ft high) with small ("microphyllous"), leathery ("sclerophyllous"), often evergreen leaves.
D. Animals: Mixture of temperate and subtropical forest and desert species.
E. Exploitation: Historically an area of small farms and limited grazing with some mining (generally without erosion or pollution control); now being intensively cut for timber

Fall foliage near the University of Maryland Campus, Maryland

Image from The Ohio State University

IX. Temperate Deciduous Forests

A. Location: Eastern portion of North America. Bounded on the east by the coastal plain along the Atlantic Ocean, the Great Plains on the West, the taiga in north and the Gulf of Mexico in the south. See this overview of the eastern section, and overview of the western section.
B. Features:
- 1. Composed of numerous, well-defined vegetation associations dominated by deciduous trees and shrubs.
  2. Variable climate, warmer and wetter in the south
  - a. Precipitation 30-60 in (75-150 cm) annually, mostly as rain
    b. Growing season of 120 (Canada) to 250 (Florida) days.
    c. Temperature extremes can be significant: -20 to -40° F to 100 to 110° F.
    d. Hurricanes and freezing rain can cause considerable physical damage to the vegetation.
    e. Soils more acid and fertile in north.
  3. Composed primarily of hardwoods with a mixture of conifers.
  4. Fire a major factor in maintaining the forest and diversity of herbs and shrubs on the forest floor
  5. Biome once wide spread across all of North America and Eurasia; flora similar to that of China today.
C. Vegetation:
- 1. Variety of hardwoods: Quercus (oak), Acer (maple), Fagus (beech), Tilia (basswood), Castanea (chestnut), and Carya (hickory). Tulip poplar (Liriodendron) also common.
  2. Scattered conifers mostly pines.
  3. Numerous shrubs, many of the heath family (e.g., Rhododendron (left), Kalmia: see below left); blueberries (Vaccinium) also common.
  4. Numerous grasses and wild flowers throughout the growing season.
  5. Associations based on combination of dominate species. Examples:
  - a. Maple-basswood: "Driftless area" of Great Lakes area.
    b. Beech-maple: Glaciated area south of Great Lakes
    c. Oak-Chestnut: East of Appalachian Mountains from Massachusetts to Georgia. Chestnut (Castanea dentata) largely killed off by fungal disease introduced around 1900.
    d. Oak-hickory: Most wide spread, both sides of the Appalachian Mountains from New Jersey to Georgia north to Minnesota. Much replaced by farm land; soil generally poor.
    e. Southern Mixed: Florida to Texas, most of the hardwoods have evergreen leaves; Spanish moss (actually a flowering plant) commonly found on the trees.
D. Animals:
- 1. Mammals: Deer; moose and bear were common; historically buffalo in the area. Raccoon and opossum common, so are skunks.
  2. Predators: Fox common; bobcat or lynx rare; wolves and mountain lion extirpated.
  3. Birds: Resident and migratory; numerous song birds and waterfowl.
Coastal Tidal Marsh, Maryland

E. History:
- 1. Only northern section directly glaciated; vegetation pushed southward into northeastern Mexico and out onto what is now the continental shelf as sea levels were lower than at present.
  2. Southeast flora not subject to extensive extinction so many relictual genera and species still persist.
  3. Chesapeake Bay and Great Lakes began to form some 10,000 years ago.
  4. Pine Barrens of New Jersey not affected by glacial epoch and flora remained in place.
  5. Isolated pockets of montane forest vegetation on coastal plains.
F. Exploitation:
- 1. No undisturbed forest due to extensive logging.
  2. Introduction of Chinese chestnut into New York Zoological Garden resulted in a fungal disease that destroyed the American chestnut.
  3. Clear-cutting of forest for farming coupled with introduction of exotic weed species has fundamentally altered the flora.
  4. Soil erosion and depletion has made it difficult for some species to re-invade disturbed sites.
  5. Erosion has resulted in silting and deposition in wetlands; some 90% of the wetlands in Maryland have been destroyed.
  6. Numerous species of plants and animals have gone extinct or have been extirpated over significant portions of their native range.

Destruction of early forest regrowth near Bethesda, Maryland

Other sites of interest
The Great Earth Gallery
Oceanography
Biomes: Excellent notes by David Bogler of the University of Texas
Biomes: A brief review
Ecological Subregions of the United States by McNab & Avers
Land-Econet: The Landscape Ecology Network
Arctic Circle: Resources on the Arctic

Rudbeckia hirta - State flower of Maryland

Main Terrestial Biome page

Part 2

Part 4