88 Ecology and Applied Environmental Science
Temperate forests generally grow in regions where the minimum temperature does not usually fall below –12°C and yearly rainfall is around
750–2000 mm. Species diversity is high. Trees are mainly deciduous but
there are also coniferous species. Consumer organisms include a great
variety of animals. The predominance of deciduous trees exerts a great
influence on the character formation of the temperate forest. It allows the
development of rich secondary vegetation under the trees, which flourishes
in the beginning of spring before the tree leaves cast their shadow on the
area, and is a significant producer for the ecosystem’s trophic chains. In the
temperate forest, due to the falling of leaves, a soil that is rich in nutrients is
created that in its turn supports complex decomposer communities as well
as those of various small-sized organisms. Thus the soil—that initially is
grains coming from rock weathering—ends up being a composite ground
ecosystem that contains microorganisms, plants and animals.
The tropical forest, what we know as jungle, develops in the equatorial zone, in regions with high average yearly temperature and rainfall. It
includes either ombrophilus vegetation with evergreen, broadleaf trees,
where humidity is high for the duration of the year, or vegetation with trees
that lose their leaves during the less humid period. The tropical forest, especially the rain forest, is characterised by an exceptionally great diversity
of plants and trees. In a few hectares, there may be more plant and insect
species than in all Europe’s flora and fauna. In many places, more than
50 tree species may be found in one hectare. The tallest trees can reach a
height of 60 meters and they often touch each other in their tallest parts
thus creating a dome of 30 meters high or more. Very little light reaches
the ground through this dome with the result that the secondary vegetation
under the trees is sporadic. There may also be a wide variety of epiphytes
that grow high on the trees, in the lighted zone, with roots that do not reach
the ground. The Amazon forest is a characteristic case.
The ratio of leaf biomass to new wood production is approximately 1:1
in the tropical rain forests, which means that they direct a much smaller
part of their production to wood storing compared to other forests. In most
tropical forests the soil is thin and poor in nutrients, because the nutrients
are washed down to the underground water table by the profuse rainfalls.
Less than 50% of the nutrients are found in the soil, versus 90% in the
European forests. The effective recycling and symbiosis mechanisms keep
the nutrients in continuous circulation inside the forest’s biomass. Through
the decomposition of leaves, nutrients are released that are very quickly
taken in by the shallow roots of the trees. If the forest is cleared, those
adaptive mechanisms are destroyed and the use of the land for cultivation
or as pasture is minimally profitable.
Scrubs with evergreen sclerophyllous plants, known as maquis, are a
characteristic forest vegetation of dry regions, where rain falls mainly in the
Temperate forests generally grow in regions where the minimum temperature does not usually fall below –12°C and yearly rainfall is around
750–2000 mm. Species diversity is high. Trees are mainly deciduous but
there are also coniferous species. Consumer organisms include a great
variety of animals. The predominance of deciduous trees exerts a great
influence on the character formation of the temperate forest. It allows the
development of rich secondary vegetation under the trees, which flourishes
in the beginning of spring before the tree leaves cast their shadow on the
area, and is a significant producer for the ecosystem’s trophic chains. In the
temperate forest, due to the falling of leaves, a soil that is rich in nutrients is
created that in its turn supports complex decomposer communities as well
as those of various small-sized organisms. Thus the soil—that initially is
grains coming from rock weathering—ends up being a composite ground
ecosystem that contains microorganisms, plants and animals.
The tropical forest, what we know as jungle, develops in the equatorial zone, in regions with high average yearly temperature and rainfall. It
includes either ombrophilus vegetation with evergreen, broadleaf trees,
where humidity is high for the duration of the year, or vegetation with trees
that lose their leaves during the less humid period. The tropical forest, especially the rain forest, is characterised by an exceptionally great diversity
of plants and trees. In a few hectares, there may be more plant and insect
species than in all Europe’s flora and fauna. In many places, more than
50 tree species may be found in one hectare. The tallest trees can reach a
height of 60 meters and they often touch each other in their tallest parts
thus creating a dome of 30 meters high or more. Very little light reaches
the ground through this dome with the result that the secondary vegetation
under the trees is sporadic. There may also be a wide variety of epiphytes
that grow high on the trees, in the lighted zone, with roots that do not reach
the ground. The Amazon forest is a characteristic case.
The ratio of leaf biomass to new wood production is approximately 1:1
in the tropical rain forests, which means that they direct a much smaller
part of their production to wood storing compared to other forests. In most
tropical forests the soil is thin and poor in nutrients, because the nutrients
are washed down to the underground water table by the profuse rainfalls.
Less than 50% of the nutrients are found in the soil, versus 90% in the
European forests. The effective recycling and symbiosis mechanisms keep
the nutrients in continuous circulation inside the forest’s biomass. Through
the decomposition of leaves, nutrients are released that are very quickly
taken in by the shallow roots of the trees. If the forest is cleared, those
adaptive mechanisms are destroyed and the use of the land for cultivation
or as pasture is minimally profitable.
Scrubs with evergreen sclerophyllous plants, known as maquis, are a
characteristic forest vegetation of dry regions, where rain falls mainly in the