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Topic of Book
Kuenneck describes the most important characteristics of Temperate Forest biomes, including Boreal Forests, Temperate Deciduous Forest and Mediterranean biomes.
The Temperate Deciduous Forest biome is one of the greatest resources in human history. It is not an accident that the three dominant civilizations of the few millennia evolved in this biome (Europe, East Asia and eastern United States). With trees, rainfall, fertile soil and rivers, this biome gives most of essential geographical ingredients for progress.
Important Points from Book
Most trees emerged during Tertiary period (<66 mya).
Boreal Forest Biome:
Were typically glaciated during Ice Age; bogs and wetlands are common; four genera of conifers dominate: spruces, firs, pines and larches; two genera of broadleaf trees are common: birches and aspens or poplars; boreal forest extend south along mountain ranges; up to six months with average temperature at or below freezing; great seasonal variation in temperature; 15-20 inches rain per year; more than half of precipitation is during summer; many lakes with slow-moving streams caused by meltwater from Ice Age; limited activities of microorganism in soil layers allow a dense mat of needles to form on soil surface; this interferes with seedlings growing; Trees in one area are often only of 1-2 types; below the canopy of trees, few shrubs grow; conical shape of trees help to shed snow; thin narrow shape of trees reduces evaporation; deciduous larches dominate where climate is too cold and dry for conifers; trees are essentially dormant during long, cold winter; trees are not very tall (50-80 ft); border region between tundra and boreal forest is fluid; frequent bogs have plants that are common to Tundra biome; since snow melts first in south portions of watershed and snowmelt cannot move north, this creates many ponds and bogs; amount and type of trees varies by proximity to bogs and slight altitude rises; large forest fires occur at intervals of 50 to 100 years; this enables tree succession of differing species; availability of nitrogen is of supreme importance to growth of conifers; moss cover sucks out water and nutrients from soil and insulates soil causing permafrost to rise; this destroys all but the most shallow-rooted trees; animals have very limited types of food; needles are not palatable to most herbivores, except their buds, and nutrient value is low; herbivores typically depend on plants on forest floor, shrubs and broadleaf trees growing in or near bogs and burn sites; animals cannot depend on seeds in cones for food and often migrate south; many mammals and birds remain in boreal forest during high seed availability; few birds are year-round residents
Temperate Deciduous Forest Biome:
Most typical trees are beeches; other typical trees are birch, maple, ash and walnut; most species-rich vegetation in the middle latitudes; since commonly have hilly or mountainous terrain, a high number of micro-climates result; annual decomposition of nitrogren-rich foliage contributes to high soil fertility; high amounts of humus enable earthworms and burrowing mammals to live and aerate the foil; due to agriculture very little of the East Asian and European forests remain; precipitation is usually evenly distributed throughout the year; growing season is typically six months long and is even longer in the southern areas; typically four distinct seasons; Alfisol soils are less weathered and develop in cooler regions; Ultisols (less fertile) are highly weathered and develop in warmer and wetter regions; Leaf that fall in autumn begin to decompose with rising temperatures in late winter and early spring, producing a humus layer; precipitation washes these nutrients into the soil just when plants need the fertilizer to grow rapidly in the spring; roots reach down into the B layer where nutrients accumulate; in spring spa rises from the roots to the branches; fresh young leaves of spring contain the highest amounts of nutrients, so insects time the hatching of larvae to this season; bird migrations are timed to meet the hatching of larvae; spring starts at the forest floor when there are no leaves on tree to block sunlight; tremendous variety of animal life; the food chain is powered by nutrient-rich plant matter in leaves, sap, seeds, nuts and berries; large proportion of bird are migratory insect-eaters;
On western edge of continents; shrubs have adaptation to drought and nutrient-poor soil and fire; broadleaf trees typically have leathery leaves and are typically evergreen; home to 20% of world’s plant species many of which are endemic to the biome; difference between coastal shrubland and interior shrubland is typical; where mountains and wind directions supports greater rainfall, woodlands can result at higher elevations; woodlands are more common toward the higher latitudes; climate is unique in that rainfall is in winter outside the growing season for plants; this causes stresses similar to desert biome;
Proximity to oceans moderates climate; there is a limited but predictable period of time in which there is both sufficient soil moisture and ample warmth to promote plant growth; no single soil type is typical of biome; soil conditions are typified by low-nutrient content in the root zone; fire is common occurrence