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FOREST ECOLOGY
DELAWARE HAS 355,00 ACRES OF
FORESTED LAND!
• Approx. 5,000 acres of timber are harvested
annually.
• Delaware’s forest products industries provide an
excess of 3,700 jobs and generate an estimated
annual wage of $98,000,000.
Delaware’s three state forests• totaling over 15,000 acres.
• providing Delawareans the opportunity for
hiking, hunting, fishing, bicycling, and
horseback riding.
• that are sustainably managed for wildlife
habitat, wood products, watershed protection,
education, and recreation.
WE ALL NEED TREES!
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OXYGEN
CLEAN WATER
PRODUCTS
FOOD
HABITAT
ASTETIC SURROUNDINGS
RECREATION
A BETTER WELL BEING
COOLER ENVIRONMENT
FOREST ECOLOGY
• the study of the complex interactions
between the LIVING (biotic) and
NONLIVING (abiotic) elements of a forest
ecosystem.
Biotic (living) components of the
Forest Ecosystem
PRODUCERS
• all green plants, trees, shrubs along with some bacteria ,
also known as an autotrophs. These organisms can
manufacture their own food using energy from the Sun.
CONSUMERS
•organisms that eat plants and animals also known as
herbivores and carnivores
DECOMPOSERS
•bacteria, fungi, insects, or other organisms that break
down organic material.
There are over 346
species of wildlife living
in Delaware of which 273
are forest dependent.
Healthy forests provide
quality habitat for wildlife
flying squirrel
box turtle
screech owl
spotted turtle
spotted salamander
Animals and insects have a huge
role in the forest.
1. decomposers breakdown organic matter
2. daily activity helps fertilize and aerate the soil
3. many serve as pollinators and seed dispersers
4. predators control harmful insects and mammals
Animals and insects can also
become a nuisance or serious
threat to a natural setting.
• excessive deer browsing on a forest’s seed crop
• squirrels and white footed mice girdle the trunks of
young trees.
• insects may reach a population that require large acres
of tree to be removed
Abiotic (non-living) components of
the Forest Ecosystem
Soil
Water
Climate
Sunlight
Slope of land
INPUTS AND
OUTPUTS OF A
FOREST ECOSYSTEM
The sequence of consumption and energy
transfer though the environment is
shown in a FOOD CHAIN. The organisms
position in the food chain is known as its
TROPHIC LEVEL.
Energy pyramids show
•Producer organisms represent the
greatest amount of living tissue or
biomass at the bottom of the pyramid.
•On average, each feeding level only
contains 10% of the energy as the one
below it, with the energy that is lost
mostly being transformed to heat.
•It takes a large number of producers to
support a small number of primary
consumers
•It takes a large number of primary
consumers to support a small number of
secondary consumers
Food Webs
Competition
in the forest
• All trees compete for the same basic
requirement of life – light, water, essential
elements, oxygen, and other necessities.
• The limiting factor in a forest ecosystem is
SUNLIGHT.
Symbiosis
- living together of two
dissimilar organisms, where one or the
other, or both are affected. Usually
involves supply of:
food
protection
cleaning
transportation or
all of the above
Mutualism is any relationship between two
species of organisms that benefits both species.
Commensalism is a relationship between two
species where one species derives a benefit from
the relationship and the second species is
unaffected by it.
Parasitism is a relationship between two
species where one species benefits and the
other is injured.
Plants are parasitized by viruses, bacteria,
fungi, nematodes, and a few other plants.
Allelopathy involves a plant's secretion of
biochemical materials into the environment
to inhibit germination or growth of
surrounding vegetation. Allelopathy
enhances tree survival and reproduction.
THE ONLY THING CONSTANT ABOUT
FOREST ECOSYSTEMS—
THEY NEVER STOP CHANGING!
NATURAL CHANGES
• fire, storms, drought, flood,
death and disease
MAN-MADE CHANGES
• harvesting, farming, trails,
development, and recreation
SUCESSION
Changes or disturbances spark the process called
succession, 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.
Intolerant Species
• Intolerant species are
generally the “first in”
after an event such as
a clear-cut or a major
fire that substantially
opens the canopy.
• These trees are often
called pioneer species.
These trees tend to:
- be fast growing
- be short-lived
- have light seeds
Sweetgum leaf
Tolerant Species
• These trees normally
are not the first to
colonize open areas.
Instead, they grow
up into an existing
canopy.
These trees tend to:
- live a long time
- grow slowly
- have heavier seeds
Beech nut
• Usually, these trees
are found in the
“climax community.”
How does succession first begin
in a disturbed area?
•bird droppings
•animals carry seeds in fur
•wind blown seeds
•existing seed bank in soil gets the needed
sunlight
•floods or high rains will leave behind seeds
Succession is healthy for a
forest:
•to better able to withstand and recover
from stress the outside environment
imposes.
•by increasing the forest’s biodiversity
allowing other species to grow.
One of Earth’s most valuable resources:
Biodiversity is the variety and complexity
of species that are present and that
interact in an ecosystem, plus the relative
abundance of each.
One of the biggest threats to
biodiversity…
Invasive Species
Plants
Insects
Diseases
Invasives often demonstrate:
rapid growth
prolific seed production
high seed germination rates
easy asexual propagation
resistance to many types of control
Many plants were that are now considered invasives where
introduced to this area intentionally for their medicinal,
ornamental, and food value. Sometimes they “hitched a
ride” in the soil, crop seeds or the ballasts of ships.
SILVICULTURE
• is the application of the principles of
forest ecology to a stand of trees to help
meet specified objectives.
– Objectives can include income, wildlife
habitat, water quality, recreation, or any
other values a forest is capable of providing.
How do we DO silviculture?
1. Determine your goals for your forest.
2. Evaluate existing conditions in the forest.
3. Decide what treatments, if any, can help
you reach your goals.
4. Implement treatments at the right time.
To cut or not to cut….
Your management goals and the shade tolerances
of the species involved will determine whether
to manage on an even-aged or uneven-aged basis.
A Rule of Thumb:
 For intolerant species, even-aged
management is best.
 Use uneven-aged management for tolerant
species.