ESPM
50AC: Introduction to Culture and Natural Resources
Handouts/
Slides: Redwood Forest Ecology
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Redwood Forest Ecology
University
of California
ESPM 50
Fall Semester, 2000
September
8, 2000
Guest Lecturer: Joe McBride
| I) Introduction | ||||
| A) Objectives | ||||
| 1) Describe the ecology of the Redwood Forest | ||||
| a) Characteristics of redwood forests | ||||
| b) Environment of the redwood forest | ||||
| c) Redwood forest dynamics | ||||
| II) Characteristics of the Redwood Forest Plant Community | ||||
| A) Dominant species | ||||
| 1) Redwood (Sequoia sempervirens) | ||||
| B) Habitat | ||||
| Ppt. | High | North Coastal Coniferous Forest | Redwood Forest | Douglas-fir Forest |
| Medium | Red Fir Forest | Mixed Conifer Forest | Mixed Evergreen Forest | |
| Low | Lodgepole Pine Forest | Ponderosa Pine Forest | Foothill Woodland | |
| Low | Medium | High | ||
|
Temperature
|
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III) Botanical Composition of the redwood forest community
| Common Name | Scientific Name | ||||
| Dominant Species: | redwood | Sequoia sempervirens | |||
| Other Trees: | grand fir | Abies grandis | |||
| Douglas-fir | Pseudotsuga menziesii | ||||
| California bay | Umbellularia californica | ||||
| tan oak | Lithocarpus densiflorus | ||||
| Shrubs: | huckleberry | Vaccinium ovatum | |||
| rhododendron | Rhododendron macrophyllum | ||||
| Ferns: | sword fern | Polystichum munitum | |||
| Herbs: | wild ginger | Asarum caudatum | |||
| redwood sorrel | Oxalis oregana | ||||
| IV) Distribution | |||
| A) Geographical Range | |||
| 1) Coastal; 10-2000'; within fog belt; ppt. 35-100"; "frost free" | |||
(Left) Location of Redwood Forests
in California
(Right) Local Placement of Redwood Forests 
| B) Local Distribution | |||
(Above) Interaction of geology, topology and climate
(Above) Typical spatial
patterns of ecosystems
| V) Response to Natural Disturbances | ||||||
| A) Fire | ||||||
| 1) Natural Frequency | ||||||
| Location (County) | Average Fire Free Interval (Years) | |||||
| Del Norte | 50 | |||||
| Humboldt | 33 | |||||
| Marin | 25 | |||||
| Alameda | 22 | |||||
| 2) Response | ||||||
| a) Redwood | ||||||
| 1) Thick redwood bark provides fire resistance | ||||||
| 2) Sprouting from Dormant Buds | ||||||
| a) Basal Sprouts | ||||||
| b) Trunk and Branch Sprouts | ||||||
| b) Response of Other Trees Species (in the Redwood Forest Community) | ||||||
| 1) Grand fir - killed by fire; cannot sprout following fire | ||||||
| 2) Douglas-fir - killed by fire; cannot sprout following fire | ||||||
| 3) California Bay - basal, trunk, and crown sprouting after fire | ||||||
| 4) Tan Oak - basal sprouts following fire | ||||||
| B) Floods | ||||||
| 1) Natural Frequency | ||||||
| a) Fifty year return interval floods result in inundation of redwood forest stands occuring on flood plains and the desposition of silt to depths of 3'+ | ||||||
| 2) Response | ||||||
| a) Redwood | ||||||
| 1) Develops new root crown when base of tree is buried in silt deposit | ||||||
| 2) Seeds gerimate readily on silt deposits. | ||||
| b)Response of other species in the redwood forest community | ||||
| 1) Grand fir - killed by flooding and silt deposits | ||||
| 2) Douglas-fir - killed by flooding and silt deposits | ||||
| 3) California Bay - survives flooding and silt disposition | ||||
| 4) Tan Oak - survives flooding and silt disposition | ||||
| VI) Succession | ||||
| A) Definition - sequential change over time in plant communities on a given site until a plant community arises which can replace itself. | ||||
| 1) Primary Succession - succession occuring on sites which have not previously support vegetation | ||||
| a) Volcanic eruption | ||||
| b) Retreat of glaciers | ||||
| c) Change in sea level | ||||
| 2) Secondary Succession - succession occuring following the destruction of existing vegetation | ||||
| a) Fires | ||||
| b) Hurricane force winds | ||||
| c) Floods | ||||
| 3) Gap Succession - succession occuring beneath gaps in the forest canopy | ||||
| a) Individual Tree Mortality | ||||
| 1) Insects | ||||
| 2) Disease | ||||
| 3) Windthrow | ||||
| B) Succession (secondary) in the redwood forest | ||||
| 1) Following Fires | ||||
| 2) Following Floods | ||||
| 3) Gap Phase Succession | ||||||
| a) Succession in the absence of perturbation | ||||||
| b) Characteristics of tree fall gaps | ||||||
| 1) Size | ||||||
| 2) Shape | ||||||
| 3) Orientation | ||||||
| 4) Frequency | ||||||
| c) Regeneration in gaps | ||||||
| 1) Redwood | ||||||
| a) Light intensity, root growth, and root pathogens | ||||||
| b) Regeneration favored in gaps | ||||||
| 2) Other species | ||||||
| a) Grand fir - can gerimate on litter in partial shade; regenerates in margins of gaps | ||||||
| b) Douglas-fir - cannot regerminate on litter; requires full sunlight; seldom succeds in gaps | ||||||
| c) California Bay - can gerimate on litter in partial shade (limited seed dispersal); regenerates in margins of gaps | ||||||
| d) Tan Oak - Can germinate on litter in partial shade (limited seed dispersal); regenerates in margins of gaps | ||||||