Question

Deciduous trees and shrubs shed their leaves seasonally in response to environmental factors. What two biomes have deciduous vegetation and what are the abiotic factors that affect leaf loss in each of them?

Your response should be at least 200 words in length.

Answer 1

ANSWER

DECIDUOUS BIOMES:

• The two biomes with deciduous vegetation include temperate deciduous forest and tropical deciduous forests.
• Deciduous plants including tree, shrubs and herbacious perennials, are those that lose their leaves for a part of the year .This process is called as abscission.

• The main abiotic factors influencing leaf loss are temperature, precipitation and sunlight.

TEMPERATE DECIDUOUS BIOMES:

Temperate deciduous forests can be found in the eastern part of the United States and Canada, most of Europe and parts of China and Japan. The temperate deciduous forest is a biome that is always changing. It has four distinct seasons: winter, spring, summer and fall. Winters are cold and summers are warm Because the soil is very fertile and hardwood trees are good for building, this biome has some of the world's largest population centers in it.

Abiotic factors that affect the leafloss:

TEMPERATURE:

• Temperature plays a key role in the balance of the deciduous forest. Warm spring months ease the plants and animals back to life, encouraging animal reproduction with the development of new leaves and plants.
• As the temperature starts to drop, the trees of the deciduous forest lose their leaves and go into a state of hibernation.
• The long winter months mean a struggle for survival during the long period when the deciduous forest is snow-covered. Plants and animals alike structure their habits and life cycles around this time.

SUNLIGHT :

• All plants need sunlight to survive, and it is this basic building block of life that has formed much of the structure of the deciduous forest.
• Trees are encouraged to grow tall; the taller the trees, the more sunlight is available to the leaves of the canopy. Beneath these tall, established trees are a shorter layer, often close to the ground.
• These ferns and shrublike bushes tend to be varieties that thrive in shady conditions, as they have to survive on what sunlight makes it through the trees. In turn, many of the herbivores in the forest are species that have adapted to live on these smaller plants.
• Adequate sunlight is essential for plants and shrubs for photosynthesis.Less the sunlight during winter more the leaf fall.

PRECIPITATION:

• The average temperature of the forest is about 50 degrees F. The average amount of rainfall in the forest is 30 to 60 inches a year. As the seasons change, so do the colors of the leaves of the deciduous.
• During the winter months water is generally not available to keep the leaves of some plants alive.
• Precipitation affected fall dormancy dates of deciduous forests across the growing season from spring to autumn.

TROPICAL DECIDUOUS BIOMES:

Tropical and subtropical deciduous forest biomes have developed in response not to seasonal temperature variations but to seasonal rainfall patterns.

Abiotic factors that cause leafloss:

• Leaf drop is not seasonally dependent as it is in temperate climates, and can occur any time of year and varies by region of the world. Even within a small local area there can be variations in the timing and duration of leaf drop; different sides of the same mountain and areas that have high water tables or areas along streams and rivers can produce a patchwork of leafy and leafless trees.
• In other parts of the world, including tropical, subtropical, and arid regions, plants lose their leaves during the dry season or other seasons, depending on variations in rainfall.
• Tropical deciduous forests occur in regions with heavy rainfall for part of the year followed by a marked dry season. These forest formations are dense and lush during the wet summers, but become a dry landscape during the dry winters when most trees shed their leaves.
• Shedding their leaves allows trees to conserve water during dry periods.
• Bare trees open up the canopy layer, enabling sunlight to reach ground level and facilitate the growth of thick underbrush. Trees use underground water during the dry seasons. These dramatic changes in water availability have a great impact on the plants and animals living in this ecosystem.

The tropical deciduous forests are sensitive to:

• Excessive burning
• Deforestation
• Overgrazing
• Exotic species.

IMPORTANT POINTS ARE UNDERLINED