24-09-2012, 03:48 PM
FOREST ECOLOGY
Forest Ecology.ppt (Size: 1.19 MB / Downloads: 44)
Forest Ecology is the study of the complex interactions between the organic and inorganic elements of a forest ecosystem.
A forest ecosystem is the organisms, soil, air and water associated with the forest.
A Forest Ecosystem Is “Interdependent”
Meaning that every organism depends on every other living and nonliving element of the system.
Living components of the forest = producers (able to make food), consumers (eats other producers and consumers), and decomposers (break down organic material).
Non-living components = soil, water and climate.
There are over 346 species of wildlife living in Delaware and of those, 273 are forest dependent. Just as these species are dependent on the forest, the forest is equally dependent on its occupiers.
HOW A TREE GROWS
Heartwood- the supporting column of inactive (dead) gap-wood which gives the trunk strength and stiffness.
Sapwood (xylem)- new layers of wood that transports water and nutrients from roots to the leaves.
Cambium- microscopic layer of cells where growth takes place.
Inner bark (phloem)- carries food made in leaves down to the branches, trunk and roots.
Outer bark- hold in moisture and protects the tree from insects and disease, excessive heat and cold, and mechanical injury.
COMPETITION
All trees compete for the same basic requirement of life – light, water, essential elements, oxygen, and other necessities.
The species that are better able to gather those requirements will out-compete others.
Succession
These changes are known as disturbances and spark the process called succession.
Succession is the gradual change in plants and animal communities over time.
Primary succession occurs in an area that has no true soil. Pioneer species are the first plants to grow at these barren sites.
Secondary succession occurs on landscapes where the natural vegetation has been removed or destroyed but the soil remains intact.
What’s your tolerance?
Tree species that first colonize an area are usually shade-intolerant species and must have full sunlight to do well.
(pines, black locust, black cherry, yellow-poplar, sweetgum, blackgum, sassafrass, and sumac)
Once they have developed some sun coverage the shade-tolerant species will begin to grow and eventually take over the canopy.
(oaks, hickories, and American beech)
Tree Classification
Trees can be classified according to the position they occupy in the forest canopy or understory. Such as system measures how well a tree has grown relative to its closet competitors. (Trees that get the most sunlight generally grow fastest).
There are five crown classes.
Delaware is a unique state !
Delaware is a unique state because the upper portion of the state lays in the Central Forest type and lower Delaware is made up of the Southern Forest type.
This means we have an interesting blend of species that have reached their most northern region and others that have reached their most southern region.