1. Ocean/Envir 260
Lecture #5:
Overview, Puget Sound
Forest Ecosystems

2. Northeast Pacific Coast Ecoregion
Northeast Pacific Ecoregion
“Globally outstanding” phenomena
Largest temperate rainforest in world
Large salmon runs
Closely related:
Forests support habitat
Salmon provide nutrients to forest and its food web
NE Pacific Coast: from mouth of Columbia to southeast Alaska, including coastal, Puget Sound rivers

3. Climate Pacific gyre Rare large-scale disturbances Mild, wet winters
Dry summer
Rare large-scale disturbances
Windstorms
Fire
Volcanic eruptions/ lahars
Major earthquakes

4. NE Pacific Forests Characteristic forests Massive, long-lived trees
Conifer dominance
Main deciduous trees
Red
alder
~100’,
100 yrs
Big
leaf maple
~80’,
300+ yrs
Douglas Fir
~250’, 750+ yrs
Western hemlock
~175’, 400+ yrs
Western red cedar
~200’, 1,000+ yrs

5. Variable conditions Rapid changes in elevation Variations in rainfall
Effects of mountains
Rain shadow
Average annual rainfall, NW Washington

6. Vegetation Zones Western hemlock (blue) Douglas fir (red)
(and red?)
Douglas fir (red)
Lowland dominance
Warmer, drier, till soils,
more frequent
disturbance
Hemlock still official
“climax” tree
Mountain species 6

7. Plant communities Smaller scale than vegetation zones Local conditions
Water, soil, light and disturbance dominant factors
Douglas fir-Pacific madrone/salal (open coastal sites)
Oregon white oak/ snowberry (wetter prairie sites)
Western red cedar – western hemlock/ devils club/sword fern (wetter forested sites)

8. Animal communities Depend on plant communities Even more diversity
Insects to birds to mammals
Majority of all species

9. Historic losses Permanent losses
Developed areas
Even where still forest, composition changes, loss of complexity
Loss of older trees
Understory loss, change
Plantations
Single species
Same age
How has this picture changed over the past century?

10. Fragmentation—effects on forest
Where forest remains, structure and composition change due to “edge effects,” i.e., vulnerability to:
Fire
Wind
Disease
Invasive species
“Checkerboard” pattern of management and ownership in Snoqualmie wildlife corridor
Exurban King County

11. Fragmentation—effects on wildlife
Eliminates, degrades connections between habitats, resulting in:
Direct deaths
Isolated “subpopulations”
Locally adapted
More easily lost
Less easily replaced
Lost genetic diversity, adaptability
I-90 east of Snoqualmie Pass
Northwest salamander

12. Wildlife effects on forest
Salmon losses:
Lost nutrients, especially riparian and stream
Extirpation of wolves
Increased elk populations
Reduced riparian vegetation
Degraded stream and riparian habitat
Grey wolf—protector of riparian vegetation?
Elk browsing on willow

13. Mixed ownership Federal State Private Generally well-protected
In-between
Private
Highly productive
Economic drivers
Global marketplace
Little compensation for public goods
Fig 9-1, Saving Puget Sound: Conservation status of Puget Sound forests 13

14. Recap: forest ecosystems
Climate drives distinguishing features
Much diversity within vegetation zones
Enormous changes, even where forest cover remains “intact”
Changes to wildlife affect forests, vice versa
Mixed management objectives, varying especially by ownership 14