DECIDUOUS FORESTSDeciduous means "falling off at maturity" or"tending to fall off", and is typically used inreference to trees or shrubs that losetheir leaves seasonally
The corresponding biome is the Deciduous Forest, or TemperateForest biome. The latitude range is anywhere from 23 ° north to 38 ° south.
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 cell wall degrading enzymes.
Severance of the leaf is aided by anatomical changes in the abscission zone where two tissue zonesdifferentiate; the one nearest the stem accumulates suberin in the cellwalls—blocking the flow of materials— while cells of the separation layer onthe blade side simply disintegrate. The suberized zone left on the stem after the leaf falls is called the leaf scar
In deciduous forests there arefive different zones Tree Stratum zone Sapling zone Shrub zone Herb zone Ground zone
Types of Deciduous Forests Temperate deciduous forest Tropical and subtropical deciduous forest
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.
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.
Tropical and SubtropicalSubtropical 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.
during the drought a leafless period occurs, which varies with species type. The shedding of leaves allows trees to conserve water during dryperiods. The newly bare trees open up the canopy layer, enabling sunlight to reach ground level and facilitate the growth of thick underbrush
HUMAN IMPACT Urbanization GlobalWarming Deforestation