Homeowner Forum / Lawn and Garden / July 2008

It's always been there.  It will always be there.  I didn't feel I had
anything to prove.  I supplied the  abstract and he didn't even read
it.

Om

Thought I'd give it a go;o)

http://www.ucmp.berkeley.edu/exhibits/biomes/forests.php

The forest biome


About 420 million years ago, during the Silurian Period, ancient plants
and arthropods began to occupy the land. Over the millions of years that
followed, these land colonizers developed and adapted to their new
habitat. The first forests were dominated by giant horsetails, club
mosses, and ferns that stood up to 40 feet tall.

Life on Earth continued to evolve, and in the late Paleozoic,
gymnosperms appeared. By the Triassic Period (245-208 mya), gymnosperms
dominated the Earth's forests. In the Cretaceous Period (144-65m mya),
the first flowering plants (angiosperms) appeared. They evolved together
with insects, birds, and mammals and radiated rapidly, dominating the
landscape by the end of the Period. The landscape changed again during
the Pleistocene Ice Ages ‹ the surface of the planet that had been
dominated by tropical forests for millions of years changed, and
temperate forests spread in the Northern Hemisphere.

Today, forests occupy approximately one-third of Earth's land area,
account for over two-thirds of the leaf area of land plants, and contain
about 70% of carbon present in living things. They have been held in
reverence in folklore and worshipped in ancient religions. However,
forests are becoming major casualties of civilization as human
populations have increased over the past several thousand years,
bringing deforestation, pollution, and industrial usage problems to this
important biome.

Present-day forest biomes, biological communities that are dominated by
trees and other woody vegetation (Spurr and Barnes 1980), can be
classified according to numerous characteristics, with seasonality being
the most widely used. Distinct forest types also occur within each of
these broad groups.

There are three major types of forests, classed according to latitude:

   * Tropical
   * Temperate
   * Boreal forests (taiga)

Temperate forest
Temperate forests occur in eastern North America, northeastern Asia, and
western and central Europe. Well-defined seasons with a distinct winter
characterize this forest biome. Moderate climate and a growing season of
140-200 days during 4-6 frost-free months distinguish temperate forests.

   * Temperature varies from -30° C to 30° C.
   * Precipitation (75-150 cm) is distributed evenly throughout the
year.
   * Soil is fertile, enriched with decaying litter.
   * Canopy is moderately dense and allows light to penetrate,
resulting in well-developed and richly diversified understory vegetation
and stratification of animals.
   * Flora is characterized by 3-4 tree species per square kilometer.
Trees are distinguished by broad leaves that are lost annually and
include such species as oak, hickory, beech, hemlock, maple, basswood,
cottonwood, elm, willow, and spring-flowering herbs.
   * Fauna is represented by squirrels, rabbits, skunks, birds, deer,
mountain lion, bobcat, timber wolf, fox, and black bear.

Further subdivisions of this group are determined by seasonal
distribution of rainfall:

   * moist conifer and evergreen broad-leaved forests: wet winters and
dry summers (rainfall is concentrated in the winter months and winters
are relatively mild).
   * dry conifer forests: dominate higher elevation zones; low
precipitation.
   * mediterranean forests: precipitation is concentrated in winter,
less than 1000 mm per year.
   * temperate coniferous: mild winters, high annual precipitation
(greater than 2000 mm).
   * temperate broad-leaved rainforests: mild, frost-free winters, high
precipitation (more than 1500 mm) evenly distributed throughout the year.

Only scattered remnants of original temperate forests remain.

Like I said, not enough colored pictures, he never read it.