Northwestern Coniferous Forest Overview

Study Notes

Overview of Northwestern Coniferous Forest

Characterized by large conifers, such as giant redwoods, and recognized as a temperate rainforest.
Features cold, snowy winters and warm, humid summers; experiences well-defined seasons lasting 4-6 months.
Geographic distribution includes Canada, Europe, Asia, and the US Pacific Northwest from California to Alaska.

Abiotic Factors

Average temperatures range from -40°C to 20°C, with summer averages around 10°C.
High precipitation levels (300-900 mm/year) occur primarily in fall, winter, and spring; summers tend to be cool and dry.
Soil is typically rocky and acidic, with elevation below 5000 ft in Northern California and below 2000 ft on the southern coast of Alaska.

Biotic Factors

Dominant tree species include Redwood and various conifers.
Understory vegetation consists of moss and various bushes.
Common insects include spiders, beetles, mosquitoes, ants, and bees.
Animal species include caribou, black bears, owls, bobcats, and weasels, while bacteria include fungi and mushrooms.

Soil Structure

Northeastern Oregon and S.Washington soil is well-drained with lower precipitation, allowing for extensive growth.
Sandy, gravelly soils are common near rivers and streams, hosting groves of pioneer species like red alder and black cottonwood.
Thick deposits of organic nutrient soil are prevalent, contributing to high moisture retention.

Landscape Structure

Forest composition features Western Hemlock, Western Red Cedar, Pacific Silver Fir, Sitka Spruce, Alaskan Cedar, and Mountain Hemlock.
This forest stretches into parts of the Rocky Mountains in Idaho and British Columbia, where Western Larch and Western White Pine thrive.

Biodiversity Patterns

Temperate evergreen forests commonly found in coastal regions with mild winters and heavy rainfall or in drier montane climates.
High biomass levels are sustained in these ecosystems, notable for large trees in temperate rainforest regions.

Animal Life

Black bears are omnivores, consuming berries and salmon, and hibernating during winter.
Bobcats are carnivores that adapt to seasonal changes in their coats for camouflage.
Various bird species, including herbivores and omnivores, migrate to warmer climates during winter.
Spotted Owls are endangered due to habitat destruction and hunting; their decline can disrupt ecosystem balance.

Geographical Area

Anchorage, Alaska, hosts a diverse population: black bears are common along with unique bluish glacier bears.
Caribou population in Alaska has declined from 490,000 in 2003 to approximately 325,000 in 2011.

Ecological Relationships

Symbiosis observed between fungi and trees, with fungi providing minerals and trees supplying carbohydrates.
Mutualism exists as squirrels gather nuts, benefiting both the trees and themselves.
Competition for food among animals like squirrels, and birds using trees for shelter without benefitting them (commensalism).
Predation example: black bears preying on insects reduces their population, while parasitism is illustrated by moss absorbing tree nutrients.

Limiting Factors

Density-independent factors include diseases like distemper in wolf packs.
Density-dependent factors involve wildfires and deforestation affecting species populations.

Growth Models

Logistic growth concept shows that as food becomes limited, populations stabilize with births equal to deaths.
Exponential growth relates to resource colonization impacts, leading to food scarcity and population declines in animals and reproduction rates.

Human Impact

Activities like deforestation, arson, and burning of fossil fuels result in acid rain and threaten plant and animal life.

Environmental Laws

Comprehensive Environmental Response, Compensation, and Liability Act mandates cleanup of hazardous substances in contaminated areas.

Description

Explore the unique characteristics of the Northwestern Coniferous Forest, also known as a temperate rain forest. This quiz covers abiotic factors, seasonal changes, and geographic areas where these forests thrive. Test your knowledge about this significant ecosystem and its diverse coniferous species.