Evergreen coniferous forests of the Pacific Northwest

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Science (Washington, D.C.); (United States)

DOI:https://doi.org/10.1126/science.204.4400.1380· OSTI ID:5673778

Waring, R H; Franklin, J F

The massive, evergreen coniferous forests in the Pacific Northwest are unique among temperate forest regions of the world. The region's forests escaped decimation during Pleistocene glaciation; they are now dominated by a few broadly distributed and well-adapted conifers that grow to large size and great age. Large trees with evergreen needle- or scale-like leaves have distinct advantages under the current climatic regime. Photosynthesis and nutrient uptake and storage are possible during the relatively warm wet fall and winter months. High evaporative demand during the warm, dry summer reduces photosynthesis. Deciduous hardwoods are repeatedly at a disadvantage in competing with conifers in the regional climate. Their photosynthesis is predominantly limited to the growing season when evaporative demand is high and water is often limiting. Most nutrients needed are also less available at this time. The large size attained by conifers provides a buffer against environmental stress (especially for nutrients and moisture). The long duration between destructive fires and storms permits conifers to outgrow hardwoods with more limited stature and life spans.

• OSTI ID: 5673778
• Journal Information: Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 204; ISSN SCIEA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
BIOLOGICAL MODELS
CENOZOIC ERA
CHEMICAL REACTIONS
CONIFERS
ENVIRONMENTAL EFFECTS
EVAPORATION
FEDERAL REGION X
FIRES
GEOLOGIC AGES
GROWTH
NORTH AMERICA
NUTRIENTS
PHASE TRANSFORMATIONS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
QUATERNARY PERIOD
SYNTHESIS
TREES
USA