DECIDUOUS FORESTSDeciduous 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

The corresponding biome is the Deciduous Forest, or Temperate Forest biome. The latitude range is anywhere from 23 ° north to 38

° south.

LEAF ABSCISSIONChemical 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 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

In deciduous forests there are five different zones

 Tree Stratum zone

 Sapling zone

 Shrub zone

Herb zone

 Ground zone

Types of Deciduous Forests

Temperate deciduous forestTropical 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 Australia There is also a bit down in

the southern tip of South America. 

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.

 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

HUMAN IMPACT

UrbanizationGlobal WarmingDeforestation