Science notes

 The Forest Ecosystem – Notes You Need!

• The forest is an ecosystem (community of living organisms interacting with

non-living components)

• The biotic (living) components include:

o All plants (producers)

o All animals (consumers- 3 types: herbivores, carnivores, omnivores)

o Earthworms, mites, millipedes, carrion beetles, ants, maggots, fungus,

molds, & bacteria/ microscopic soil organisms (decomposers)

• The abiotic (non-living) components include:

o Water

o Rocks & soil

o Sunlight & air

o Chemicals

• Trees have a significant affect on conditions inside the forest (under the

canopy)

o They break the wind: with less air movement, there is less drying

o They shade the ground, this lowers the air temperature and also

reduces drying

o This causes forests to be more humid with moist soil

o They contribute leaves, branches and stems to the material on the

forest floor that decomposes into humus

• Herbivores (like deer and caterpillars) can have a negative effect on plants

and trees because they eat the leaves – tent caterpillars consume every part

of the tree that is edible to them – spruce bud worms kill the growing shoots

of spruce trees – Yellow-bellied Sapsuckers peck rows of shallow holes

around the trunk of trees to draw out sap – blight and other fungi/bacteria

gets on leaves, then travels into the wood of tree stems, destroying the leaves

and sections of the tree

• There are 4 levels of the forest: canopy, understory, floor and subfloor

o The canopy: is the top level, is formed by the leaves and branches of

the tallest trees. Up to 35% of precipitation that falls on a forest is

intercepted by the canopy. Different birds (owls, orioles) and insects

(aphids, tent caterpillars) live here.

o The understory: is home to the smaller trees and larger shrubs. It

provides sheltered space for birds and small mammals to travel.

Many insects, lichen, squirrels, woodpeckers and many other birds

can be found here.

o The forest floor: ferns, wildflowers, and other soft stem plants, tree

seedlings, butterflies, dragonflies, mice, weasles, deer, skunks, and

rabbits live and find their food sources here.

o The subfloor: includes the soil, leaf litter, mushrooms, insects,

salamanders, toads, and moss. The soil is a storehouse for growth and

covers the bedrock. Worms, bacteria, soil insects, tree roots, spiders,

millipedes and centipedes are found here.