More about Birds in Redwood Forests

A study in Mendocino County, California, investigated the association of wildlife with individual redwoods and documented in detail how the greater structural complexity of legacy trees resulted in greater diversity and richness of wildlife when compared to control trees that were the size of commercially mature redwoods (Mazurek and Zielinski 2004). 

Wildlife (especially birds) were nine times more abundant in legacy trees than in control trees (Mazurek and Zielinski 2004).  Foraging activity was twice as high in legacy trees compared to control trees (Mazurek and Zielinski 2004).  Many species of birds and mammals were seen or detected only in the legacy trees, never in the control trees.  This does not mean that these animals never visit the control trees, but it shows the extent to which the legacy trees are far more important to them.

In contrast to control trees, legacy trees have well-developed canopy communities, large flat branches for nesting and growing epiphytes, and their bark and foliage harbor more arthropods .  Also, many legacy redwoods have basal hollows caused by "periodic fires that produce repeated scarring and healing."  These cavities have interior heights greater than the height of their openings, and are used extensively as concealed nesting places by Vaux's Swifts, Violet-green Swallows (Tachycineta thalassina), Pygmy Nuthatches (Sitta pygmaea) and bats such as the Long-legged Myotis (Myotis volans) (Mazurek and Zielinski 2004). 

Unfortunately it is unknown if predation rates in residual and legacy trees are as low as those of the surrounding forest or of unlogged redwood forests.  Researchers have found that ducks nesting in small grassland tracts are often preyed upon more frequently than ducks nesting in large unfragmented grasslands, because predators can find bird nests more easier with smaller areas to search.  A similar situation may or may not occur with "residual"  and "legacy" redwoods, and the possibility that such trees may act as "sinks" rather than "sources" for some species of wildlife (Pulliam 1988) needs to be carefully studied.

The Future of Redwoods

Only 4% of the original ancient Coast Redwood forest remains.  The other 96% has been logged within the last 200 years (Hunter and Bond 2001).  This unfortunate fact means, among other things, that the unique community of plants and animals that lives in the canopy of the redwood forest is endangered, since it takes many hundreds of years for these complex treetop communities to develop.  Some redwood forests logged in the past 200 years have now grown back to the point that their trees are big enough to start collecting canopy soils and epiphytes, but these redwoods are usually cut again for timber before their canopy communities become fully developed.

Another  long-term threat to the redwood forest comes from climate change.  Over the past hundred years, the frequency of fog in the redwood region has declined by 33% (Johnstone & Dawson 2010).  Because redwoods and many other plants of the redwood forest uptake some of their water through their leaves directly from fog, continued decrease in fog frequency could eventually make it more difficult for the redwood forest to survive (Ahuja 2011).

References

Ahuja MR  (2011)  Strategies for conservation of germplasm in endemic redwoods in the face of climate change: a review.  Plant Genetic Resources 9: 411-422

Azvedo J, Morgan DL  (1974)  Fog precipitation in coastal California forests.  Ecology 55: 1135-1141

Baker LM, Peery MZ, Burkett EE, Singer SW, Suddjian DL, Beissinger SR  (2006) Nesting habitat characteristics of the Marbled Murrelet in Central California Redwood Forests.  Journal of Wildlife Management 70: 939-946

Brand LA, George TL  (2000)  Predation risks for nesting birds in fragmented coast redwood forest.  Journal of Wildlife Management 64: 42-51

Brand LA, George TL  (2001)  Response of passerine birds to forest edge in coast redwood forest fragments.  Auk 118: 678-686

Burgess SSO, Dawson TE  (2004)  The contribution of fog to the water relations of Sequoia sempervirens (D. Don): foliar uptake and prevention of dehydration.  Plant Cell and Environment 27: 1023-1034

Byers HR  (1953)  Coastal redwoods and fog drip.  Ecology 34: 192-193

Cooperrider A, Noss RF, Welsh HH, Carroll C, Zielinski W, Olson D, Nelson SK, Marcot BG  (2000)  Terrestrial fauna of redwood forests.  Pp. 119-163 in The Redwood Forest (Noss RF, ed.), Island Press, Washington DC

Dawson TE  (1998)  Fog in the California redwood forest: ecosystem inputs and use by plants.  Oecologia 117: 476-485

Hunter JE, Bond ML  (2001)  Residual trees: wildlife associations and recommendations.  Wildlife Society Bulletin 29: 995-999

Jackman TR  (1998)  Molecular and historical evidence for the introduction of Clouded Salamanders (genus Aneides) to Vancouver Island, British Columbia, Canada, from California.  Canadian Journal of Zoology 76: 1-11

Johnstone JA, Dawson TE  (2010)  Climatic context and ecological implications of summer fog decline in the coast redwood region.  Proceedings of the National Academy of Sciences 107: 4533-4538

Koch GW, Sillett SC, Jennings GM, Davis SD  (2004)  The limits of tree height.  Nature 428: 851-854

Koford CB  (1953)  The California Condor.  National Audubon Society Research Report 4.

Limm EB, Simonin KA, Bothman AG, Dawson TE  (2009)  Foliar water uptake: a common water acquisition strategy for plants of the redwood forest.  Oecologia 161: 449-459

Mazurek MJ, Zielinski WJ  (2004)  Individual legacy trees influence vertebrate wildlife diversity in commercial forests.  Forest Ecology and Management 193: 321-334

Meyer CB, Miller SL, Ralph CJ  (2004)  Stand-scale habitat associations across a large geographic region of an old-growth specialist, the Marbled Murrelet.  Wilson Bulletin 116: 197-210

Pulliam HR  (1988)  Sources, sinks and population regulation.  American Naturalist 132: 652-661

Russell WH, Jones C  (2001)  The effects of timber harvesting on the structure and composition of adjacent old-growth coast redwood forest.  Landscape Ecology 16: 731-741

Sawyer JO, Sillett SC, Popenoe JH, LaBanca A, Sholars T, Largent DL, Euphrat F, Noss RF, Van Pelt R  (2000)  Characteristics of Redwood Forests.  Pp. 39-79 in The Redwood Forest (Noss RF, ed.), Island Press, Washington DC

Sillett SC  (1999)  The crown structure and vascular epiphyte distribution in Sequoia sempervirens rain forest canopies.  Selbyana 20: 76-97

Sillett SC, Bailey MG  (2003)  Effects of tree crown structure on biomass of the epiphytic fern Polypodium scouleri (Polypodiaceae) in redwood forests.  American Journal of Botany 90: 255-261

Sillett SC, Van Pelt R  (2000)  A redwood tree whose crown is a forest canopy.  Northwest Science 74: 34-43

Sillett SC, Van Pelt R  (2007)  Trunk reiteration promotes epiphytes and water storage in an old-growth redwood forest canopy.  Ecological Monographs 77: 335-359

Snyder NFR, Ramey RR, Sibley FC  (1986)  Nest-site biology of the California Condor.  Condor 88: 228-241

Spickler JC, Sillett SC, Marks SB, Welsh HH  (2006)  Evidence of a new niche for the North American salamander Aneides vagrans residing in the canopy of old-growth redwood forest.  Herpetological Conservation and Biology 1: 16-26

Sterling J, Paton PWC  (1996)  Breeding distribution of Vaux's Swift in California.  Western Birds 27: 30-40

Williams CB, Sillett SC  (2007)  Epiphyte communities on redwood (Sequoia sempervirens) in northwestern California.  Bryologist 110: 420-452

Zielinski WJ, Mazurek MJ  (2007)  Identifying the species of bats roosting in redwood basal hollows using genetic methods.  Northwest Science 81: 155-162

Information about this Review

The author is:  Dr. Paul D. Haemig (Sweden)

The proper citation is:

Haemig PD  2012    Ecology of the Coast Redwood.  ECOLOGY.INFO 20.

The redwood photograph at the top of this page was taken by M. Douglas Wray (USA) at Muir Woods National Monument, California, the last remaining old-growth redwood forest in the San Francisco Bay area.  The photograph is titled "Redwood Cathedral."

If you are aware of any important scientific publications about the Coast Redwood that were omitted from this review, or have other suggestions for improving it, please contact the author at the following e-mail address: 

haemig {at} ecology.info 

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