Deciduous forests are characterized by trees that shed their leaves seasonally. There are five zones within deciduous forests: tree stratum, sapling, shrub, herb, and ground. Leaf abscission is aided by anatomical changes in the abscission zone and production of reactive oxygen species. The two main types are temperate deciduous forests, found in parts of North America, Europe, Asia, and South America, and tropical/subtropical deciduous forests, which have long dry seasons causing trees to shed leaves. Human impacts on deciduous forests include urbanization, global warming, and deforestation.
1. DECIDUOUS FORESTS
Deciduous means "falling off at maturity" or
"tending to fall off", and is typically used in
reference to trees or shrubs that lose
their leaves seasonally
2. The corresponding biome is the
Deciduous Forest, or Temperate
Forest biome. The latitude range is
anywhere from 23 ° north to 38 °
south.
3.
4. LEAF ABSCISSION
Chemical mechanism
◦ A variety of reactive oxygen species or
"ROS" (namely H2O2, but
also superoxide, singlet oxygen and radical
hydroxyl) are generated by plants during
times of stress (biotic and abiotic)
including UV light, cool
temperatures, excessive
light, pathogens, parasites, and high salinity.
The presence and continuous production of
these ROS causes disruption in the
homeostasis of the cellular
components, leading
to metabolic dysfunction and expression of
5. Severance of the leaf is aided by
anatomical changes in the abscission
zone where two tissue zones
differentiate; the one nearest the stem
accumulates suberin in the cell
walls—blocking the flow of materials—
while cells of the separation layer on
the blade side simply disintegrate. The
suberized zone left on the stem after
the leaf falls is called the leaf scar
6.
7. In deciduous forests there are
five different zones
Tree Stratum zone
Sapling zone
Shrub zone
Herb zone
Ground zone
8.
9. Types of Deciduous Forests
Temperate
deciduous forest
Tropical and
subtropical
deciduous forest
10. Temperate Deciduous Forests
The temperate deciduous forest has
a temperate of four seasons. Temperate
deciduous forests get about 950 to 1500
millimeters of rain annually, which is the
second most of all the biomes. They
have summer highs of about 27 to 32°
Celsius with winter lows of around -1 to -
15° Celsius.
11. Temperate forests are found in the
eastern 1/3rd of North America,
in western Europe,
in China, Korea, Japan and Australi
a There is also a bit down in the
southern tip of South America.
12. Tropical and Subtropical
Subtropical Forests
is located at tropical and subtropical
latitudes. Though these forests occur
in climates that are warm year-
round, and may receive several
hundred centimeters of rain per
year, they have long dry
seasons which last several months
and vary with geographic location.
13. during the drought a leafless period
occurs, which varies with species
type. The shedding of leaves allows
trees to conserve water during dry
periods. The newly bare trees open up
the canopy layer, enabling sunlight to
reach ground level and facilitate the
growth of thick underbrush
14. HUMAN IMPACT
Urbanization
GlobalWarming
Deforestation