3. Definition:
• Natural, gradual changes in the types of
species that live in an area; can be
primary or secondary.
• The gradual replacement of one plant
community by another through natural
processes over time
4. Primary vs. Secondary Succession:
• Primary succession: beginning from an abiotic
environment following a cataclysmic
disturbance
• Secondary succession: beginning from a major
disturbance, but all forms of life are not
destroyed
5. Primary Succession
• Begins in a place without any soil
– Sides of volcanoes
– Landslides
– Flooding
A.Starts with the arrival of living things such
as lichens that do not need soil to survive
• Called PIONEER SPECIES
6. What is lichen?
• Symbiotic relationship between fungus
and algae.
– Fungus = the house
– Algae = photosynthesizing energy producer
7.
8. Primary Succession
B. Soil starts to form as lichens and the
forces of weather and erosion help break
down rocks into smaller pieces
– When lichens die, they decompose, adding
small amounts of organic matter to the rock to
make soil
10. Primary Succession
C. Simple plants like mosses and ferns can
grow in the new soil
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11. Primary Succession
D. The simple plants die, adding more
organic material
– The soil layer thickens, and grasses,
wildflowers, and other plants begin to take
over
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12. Primary Succession
E. These plants die, and they add more
nutrients to the soil
– Shrubs and trees can survive now
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13. Primary Succession
F. Insects, small birds, and mammals have
begun to move in
– What was once bare rock now supports a
variety of life
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14. 2. Secondary Succession
A. Begins in a place that already has soil
and was once the home of living
organisms
i. Occurs faster and has different pioneer
species than primary succession
ii. Example: after forest fires, logging,
cultivation
20. Primary Succession (forest)
• Colonization: of bare rock, tiny seedless plants like
mosses, and lichens, “pioneer species”
• Early: plants typically small with short lifecycles
(annuals), rapid seed dispersal, “environmental
stabilizers”
• Middle: plants typically longer lived, slower seed
dispersal (herbs, shrubs, perennials)
• Late: plant species are those associated with older,
more mature ecosystem-largest vegetation (trees)
• “Climax Community” mature forest in this case (but
varies by biome)
23. Herb/ Pioneer Stage
• This stage contains seed plants whose stems
wither away to the ground each winter.
• Insects and small rodents feed on the grasses,
herbaceous plants, and seeds
• As the diversity of plants increases so does the
variety of wildlife species.
24. Oregon Species
• Lichen and mosses (wolf
lichen, Evernia, etc.)
• Wildflowers like Broadleaf
Lupine (Lupinus latifolius)
and Camass (Casassia
leichtlinii)
• Native grasses like Idaho
fescue (Festuca
idahoensis)
25. Shrub Stage
• Usually low woody plants with several
permanent stems instead of a single trunk
• Larger variety of wildlife attracts predators
26. Oregon Species
• Bunchberry (Cornus canadensis)
• Kinnikinick/ Bearberry
(Arctostaphylos uva-ursi)
• Snowberry (Symphoricarpos
mollis)
• Hahale Mat (Ceanothus
prostratus)
• Poison Oak (Todicodendron
diversilobum)
• Big Leaf Maples (Acer
macrofolium) begin to
germinate
27. Young Forest Stage
• The quantity and diversity of shrubs and
herbaceous plants decreases
• With less variety in food available, the
number of wildlife species decreases.
• Birds of prey nest in the trees of a young
forest
28. Oregon Species
• Pine species (Sugar pine
and Ponderosa Pine)
begin to grow quickly
• Madrones have sprouted
and grow quickly
– Fast-growing species take
advantage of the excess light
available
29.
30. Mature Forest Stage
• Hardwood trees begin to die, opening the
canopy for the growth of spruce
• Shrubs return and make more food and
cover available to songbirds, game birds,
and rodents.
• Late- successional species begin to
dominate (Grand fir, white fir, Douglas-fir)
31. Oregon Species
• Mix of pines and firs at multiple ages
– Ponderosa Pine
– Douglas Fir
– Sugar Pine
– Incense Cedar
• New group of plants begin to colonize the
forest floor (ferns, wild flowers, some
shrubs
32.
33.
34. Climax Forest Stage
• Theoretical phase due to disturbances that alter the
forest throughout the other stages.
• Dead trees called snags provide homes for woodpeckers
and other cavity-nesting birds.
• A stable group of plants and animals that is the end
result of the succession process
• Does not always mean big trees
– Grasses in prairies
– Cacti in deserts
35. Dominant Oregon Species
• Western Hemlock (Tsuga heteroplolla)
• Ponderosa Pine (Pinus ponderosa)
• White Fir (Abies concolor)
• Red Fir (Abies magnifica)
• Grand Fir
• Sugar Pine
38. • Klamath Mountains
• Mixed conifer forests in the Klamath Mountains ecoregion
are characterized by conifers but have high tree diversity.
Douglas-fir is usually dominant. Depending on site
characteristics, other canopy trees include white fir, sugar
pine, ponderosa pine, and incense cedar. Port-Orford
cedar occurs on moist sites, such as riparian areas. Jeffrey
pine and knobcone pine occur on serpentine soils.
Broadleaf trees, such as tanoak, canyon live oak, golden
chinquapin, and Pacific madrone, may occur in the
subcanopy. Understories are mostly dominated by shrubs
but can be dominated by forbs, graminoids, or may be
relatively open.
40. West Cascades
•Coniferous forests dominate the landscape of the West
Cascades ecoregion. Late Successional Conifer Forests are older
forests (hundreds of years old), generally occurring below 3,500 feet,
but sometimes occurring up to 4,000 feet. Douglas-fir trees occur up to
5,000 feet but do not dominate the forests at higher elevations.
Western hemlock is almost always co-dominant and usually dominates
the understory. Other common trees include grand fir and western
redcedar in the northern portion of the ecoregion, or incense cedar,
sugar pine, white fir, and western redcedar in the southern portion of
the ecoregion. The understory has shrub and forb species, such as
vine maple, salal, sword fern, Cascade Oregon grape, western
rhododendron, huckleberries, twinflower, deerfoot, vanillaleaf, and
oxalis. In the absence of disturbance, Douglas-fir forests eventually will
convert to western hemlock.
41. East Cascades
• East Cascades
• Mixed conifer forests span the eastern slopes of the Cascade
Mountains. This habitat contains a wide variety of tree species and
dominance patterns. Douglas-fir, grand fir, and western hemlock are
the most common forest tree species and co-dominate most
overstories. Several other conifers may also be present, including
western red cedar, western white pine, western larch, ponderosa
pine, and lodgepole pine. Undergrowth vegetation in the East
Cascades includes vine maple, Oregon grape, huckleberry, oxalis,
boxleaf, thimbleberry, and twinflower. Many sites once dominated by
Douglas-fir and ponderosa pine (and formerly maintained by
wildfire) may now be dominated by grand fir (a fire sensitive, shade-
tolerant species).
