Life History and Ecological Guide to the Coast Redwood
Life History and Ecological Guide to the
Coast Redwood, Sequoia sempervirens
Natural History Instructors, Interpretive Specialists,
The Plant Communities, Biota, and Topography of the
Mangels Ranch Area of the Forest of Nisene Marks State Park
Daniel J. Miller
Listing of Figures and Tables (iv)
Why I Wrote the Guide (vi)
California State Park Department Request (viii)
Primary Value of the Guide (x)
Changes in Cultural Values Regarding the Redwood 1
Scope and Format of the Guide 4
SECTION I. Defining the Ecosystem and Topography for the Mangels Ranch area 7
Plant Communities 7
Vegetative Climax and Seral Stages 8
Topography, Geology, and Climate 9
East and West Facing Slopes of the Mangels Ranch Area 10
Soil Types, Floods, Landslides, and Slump Jumbles 12
SECTION II. Summary of Redwood Structures and Adaptations 14
The Redwood as a “Superlative” Tree 14
Is the Official Common Name Redwood or Coast Redwood? 14
The Public’s Imagery of the Redwood 14
Official State Trees, and The Tallest Tree in the World 15
Maximum Diameters of the Redwood and Giant Sequoia 15
Maximum Ages of Redwood and Other Very Old Trees and Plants 16
Basic Redwood Structures and Adaptations 16-24 (Figures 4.1-4.17)
Forests, Stands, and Groves 25
Treefall Gap, Root-pull Pit, and Rootwad 25
Harvesting Effects: Percent Remaining of Old-growth Redwood 26
Definition of an Old-growth Redwood Tree 27
Forestry Criteria of the Extent of Logging 28
Unlogged Old-growth Forests - First Generation Redwoods 28
Residual Old-growth and Residual Second Growth - 29
Second-growth Forest - Second Generation Trees 30
Third-growth Forest - Third Generation Trees 30
Redwood Distribution - Past and Present 31
Sea Salt Desiccation 31
Seed Germination 31
Survival of Seedlings 33
Tannins and Phenolics 33
Determining the Age of a Redwood 33
Official Size Classification of Redwood Trees Based on dbh Diameter 34
Nursery Logs, Nurse Trees, and Nurse Plants 34
Role of Fog Drip 37
Role of Litter, Duff, and Humus 38
Role of Fire 39
Fire Scars Creating Changes in Growth Rings 39
Mean Fire Interval (MFI) 40
Lightning-Volcano Fire Regime - up to 11,000 years BP 41
Aboriginal Fire Regime - 11,000 years ago to 1792 41
Spanish-Mexican Fire Regime - 1792-1848 43
Anglo Fire Regime -1848-1929 44
Recent Fire Regime - 1929-present 45
Fire Scars, Fire Cavity, Chimney Tree, and Goosepens 46
How These Fire Data Relate to Redwoods in Mangels Ranch Area 46
Root and Trunk Functions 48
Albino Redwoods, Tumorigenesis, and Epiphytes 49
Structures Originating From Dormant Buds 50
Growth Regulators, Sprouts (clones) 50
Sprout Rings (Fairy Rings) 51
Tree Members Comprising a Redwood Sprout Ring May Not Be Sprouts
From the Same “Mother” Tree 52
Corralitos, Christmas Tree, Stump Peeler 53
Piggyback Tree 54
Trunk Sprouts, Lignotubers, and Burls 55
Willis Jepson’s 1910 “Circle” 57
Types of Redwood Clusters 61
Slump Jumbles Are a Form of Creep Gravitational Erosion 62
Slump Jumble Clusters 69
Slump Jumble Cluster Formation 69
Initial findings of Cluster Study in Happy Valley 70
Confirmation of Slump Jumble Cluster Process by Geologist 71
Self-pruning of Redwoods 72
Creosote Bush Expanding Circles in the Mohave Desert 72
Present Development of a Potential Cluster in Happy Valley 73
Summary of Slump Jumble Cluster Criteria 76
Slump Jumble Clusters in Adjacent Forest Stands 76
Dominant Plant Species in Slump Jumble Cluster Area 77
Wildlife Events and Listing of Plants and Animals in the Mangels Ranch Area 78
Appendix I - The Mill Valley Cluster (Jepson’s Circle) 89
Appendix II - Examples of tree growth in response to light, ground water, rainfall, and
injury to the cambium of a redwood downed in Mangels Ranch Area. 95
Literature Cited 102
Book Reviews of Redwood Literature for Interpreters and Docents 106
LISTING OF FIGURES
Figure 1. Lower Area of the Forest of Nisene Marks State Park noting location of
Mangels Ranch Area, George’s Flat, Buggy Trail, and the Pourroy Trail area. 5
Figure 2. Topography and vegetative classification of the Mangels Ranch Area. 6
Figure 3. Soil types in the lower area of Nisene Marks State Park, with emphasis on the
highly erodable loam extending through Happy Valley. The loam is labeled #112,
and is enhanced in this figure. Map from Bowman13, 1980
Figure 4. Drawings of redwood growth forms, Figs. 4.1- 4.17. 17-24
Figure 5. Fifty-year coverage of wildfires in Lightning and Recent Regimes. Fires less
than 10 acres are not mapped. Maps from Greenlee and Langenheim42
Figure 6. Distribution and size of redwoods in Piggyback slump jumble cluster. 63
Figure 7. Distribution and size of redwoods in Tent slump jumble cluster. 65
Figure 8. Distribution and size of redwoods in Grand Cluster. 67
Figure 9. New cluster forming on level ground downwind of a large slump jumble
Figure 10. Distribution and size of redwoods in the Mill Valley Cluster in Old Mill Park,
Mill Valley. 93
Figure 11. Photographs of redwood trees in a section of the perimeter trees of the
Mill Valley Cluster. Note the enlarged buttresses and adjoining burl and lignotuber
growths due to heavy use. 94
Figure 12. Annual rainfall from 1970-2004 compared with growth of annual rings of a
25 inch (avg. dbh) redwood downed in January, 2005 in Mangels Ranch Area (see
also Figure 4.4). 98
LISTING of TABLES
TABLE 1. Mammals Observed in the Mangels Ranch Area. 85
TABLE 2. Amphibians and Reptiles Observed in the Mangels Ranch Area. 85
TABLE 3. Birds Observed in the Mangels Ranch Area. 86
TABLE 4. Partial Listing of Common Native Plants in the Mangels Ranch Area. 87
TABLE 5. Listing of Introduced Invasive Plants in the Mangels Ranch Area. 88
In 1996 I was active with “Friends of Nisene Marks State Park”, a group of Santa Cruz
county residents (mostly Aptos) who were trying to prevent a small forest of uncut old-growth
redwoods from being harvested in the Mangels Ranch Area. My contribution to their
eventually successful effort was to engage in redwood research and ecological studies. Much
thanks is offered to these community activists.
Executive Director Margaret Eadington of The Trust for Public Land (TPL) asked me
to show the property to an individual who later donated to the TPL to buy the property.
Environmental counsel Keith Sugar ably assisted. My thanks to Margaret and Keith. In
1999, The Trust for Public Land donated the property to the California State Parks (CSP). The
Life History and Ecological Guide to the Redwood arose out of my earlier action to protect
the forest for educational and contemplative use. I received help from many sources while
compiling the Guide. My wife Pat edited much of the text. Our son Steven and daughter Kitty
took photographs, recorded data in the field, and assisted in laying out alternative proposed
Members of Friends of Nisene Marks State Park gave their enthusiastic assistance.
Among them were Agnes Van Eck Reed and Karl Mertz, both of them members of the
Mangels family as well. Other Friends of Nisene Marks State Park members who helped were
Sandy Henn, Linda Sanguino, Jim and Peggy Crocker, Don Richards, and Diane Strickland.
California State Park officials and personnel gave much encouragement and help.
David Vincent, Superintendent of the Santa Cruz County Area, was always available for
consulting, and to give me permission to gather information in the park.
Retired Superintendent Ralph Fairfield gave me exceptional assistance in my studies.
The personnel of The Forest Nisene Marks State Park were helpful, especially
Supervisor Nedra Martinez and Barbi Barry (maintenance and trails). Park Rangers Chris
Sanguino and Mike Romniger assisted, with Mike transporting me to the far ends of the park.
I received greatly appreciated direction from Superintendent Kirk Lingenfelter, a recognized
master of trail construction. It was Kirk who made the suggestion I submit a proposal for use
of the Mangels Ranch Area when it is opened to the public.
The ecology staff, George Gray, Chris Spohrer, and Tim Hyland helped in many ways
to stress the ecological values of this area. Interpretive specialist Julie Sidel, after reading the
draft of the Guide, invited me to a docent training session.
Exceptional thanks is due to Thom Sutfin, Edgar Orre, and Denise Muir of the
California Forestry and Fire Protection Department’s Soquel Demonstration State Forest
office. Forestry Manager Thom Sutfin spent considerable time editing figures and some
sections of the text, and secretary Denise Muir was very helpful as a line editor for some of
Randy Widera, Executive Director of the Friends of Santa Cruz State Parks, helped
with the text and with advice. Heather Butler, Director of the Web of Life Field (WOLF)
School environmental school for students, helped with the editing.
Dave Stockton of the Humboldt Redwoods State Park, and James Wheeler of the
Redwoods National Park, gave up-to-date-information on which redwood is currently the
Dr. Dean Taylor of the Jepson Herbarium at Berkeley gave valuable new information
that the Interior Live Oak previously identified in Santa Cruz county (and south along the
coast to near Santa Barbara), is actually the Shreve oak, Quercus parvula var shrevei.
Dr. Richard Beidleman of the Jepson Herbarium searched Willis Jepson’s field notes
and found important data collected in 1898 by Jepson on a circle of redwoods in Mill Valley.
This information is important for present studies on redwood genetics and cluster formation.
Dr. Peter Del Tredici of the Arnold Arboretum of Harvard University sent me
information and publications on lignotubers and cluster formation. Extremely helpful with the
“Jepson circle” research were Joyce Crews, History Room Librarian at the Mill Valley Public
Library, and Peggy Chenoweth, Board of Directors of the Mill Valley Historical Society.
Alan Kunze, geology graduate student at Fresno State University, substantiated that
some redwood clusters in Happy Valley established themselves in areas where mineral soil
was exposed by slump jumbles.
Toward giving clear explanation in the Guide of cluster formation and redwood
growth, I had correspondence and phone conversations with Reed Noss (The Redwood Forest,
Lit. citation 5), and John Evarts (Coast Redwood, Lit. citation 24). Their interest in redwood
growth patterns was very helpful.
I am sure I have overlooked acknowledging many persons who have been generous
with their help. I thank all of you not mentioned, and thank those persons who undertook
action on their own to help develop the Mangels Ranch Area into an exceptional nature study
park. - Daniel J. Miller, 2005
WHY I WROTE THIS GUIDE - Natural History Experiences and Education
Over the past eleven years, I have been a volunteer Natural History speaker in 6-12th
grade classes in Santa Cruz County and the three adjoining counties. Over 9600 students
attended my presentation titled, The Environment and Population Growth. Part of my
commitment to writing this Guide comes from the discussions I have had with these students
and their teachers. I have also led nature study hikes for 4H members in Santa Cruz County
for several years.
I was encouraged to find that students were aware of the environmental movement.
But many of them did not realize that Recycle, Reduce, and Re-use are not the only actions
needed. The teachers recognize this problem and contact me because I emphasize the basic
principles of ecology which are needed to protect renewable resources. An ecological
understanding leads to realizing the value of sustaining and protecting the life-supporting
ecosystems for all animals, including humans. I explain in the classrooms why the remaining
50 percent of the world’s forests must be given much more attention not only for protection of
the remaining flora and fauna in the forest, but mainly for the survival of human cultures.
My reception in classes was enhanced not only by my profession as a marine biologist,
but being able to anecdotally relate my naturalist experiences. As a child and since, I was
always very close to nature and obsessively wanted to know about the plants and animals
These early experiences included moving in 1932 to Chicago Park, near Grass Valley,
where my father bought five acres. The major plants on the property were grass, Ponderosa
and gray pines, incense-cedar, and manzanita. My father cut down Ponderosa pines in a
nearby forest, dragged them in by horse, and by himself built a small two-story log house. Our
two-children family camped under the Incense-cedars for two summers, and spent one winter
in the chicken house. We had to keep our milk goat near us at night while we were camping to
protect her from the bands of coyotes.
We saw coyotes regularly because of a large brush fire nearby several years before.
Effects of the fire increased rodents which were probably the coyote’s main food. Witnessing
the function of predator-prey relationships and watching the growth recovery of the original
vegetation was a first-hand ecological education. Ecological concepts were not discussed in
the family--we simply were aware of what was happening around us. I don’t remember being
told not to run away from large predators, but possibly I had some basic instinct at age seven
which told me not to. By myself, and in the forest some distance from home, I came upon
several coyotes who were staring at me about 100 feet away. I froze in my tracks. They stared
at me for a short while, then trotted away.
In WWII, I was in Italy as a medical aid man with the infantry in the 10th Mountain
Division. For the first time, I saw a land that was devoid of a wilderness feeling. The forest
trees were mostly in rows and when a limb fell it was immediately picked up for fuel. Wild
animals were vulnerable and scarce during wartime.
When I returned from Europe, I went to UC Berkeley. I signed up for Aldo Starker
Leopold’s ecologically oriented Wildlife Conservation major. Included were several courses
in forestry, botany, ecology, paleontology, and geomorphology. One of my concerns was the
over-exploitation of wildlife areas because of the expanding U.S. economy and exponential
world population growth after the war.
My California Department of Fish and Game (CDFG) experiences started in
1949 on a Klamath River salmon and steelhead survey near Oregon, near Mt. Shasta I
conducting a summer creel census at a high mountain lake, then worked in game management
in desert areas constructing watering devices for birds. My first hand field work gave me a
broad ecological awareness. In 1951, I transferred to the Marine Fisheries Branch of the
CDFG, where I conducted marine fish life histories, headed the state’s sea otter project, made
a study of shark attacks on humans along the Pacific coast, and captured and tagged harbor
seals at the mouth of the Klamath River. I also conducted marine sport fishery use and catch
surveys from Oregon to Pt. Conception.
Introduction to Mangels Ranch Area
When my wife, children, and I moved to Aptos in 1962, our property abutted the 95
acre Mangels Ranch Area. A new owner bought that property in 1986, and by 1996 the
property was under chapter eleven of the federal bankruptcy court. The judge recommended
that the owner obtain a Timber Harvest Plan to help pay the debts.
With the owner’s permission, I conducted a timber cruise of the property, measuring
the width of over 800 redwoods two inches or more in diameter. The study convinced the
owner, the judge, and the three trustee holders that the forested property was more valuable
uncut than cut. I and 30 local residents initiated action that led to The Trust for Public Land
purchasing and then donating the Mangels Ranch Area to the California State Parks in March,
1999. More than 600 of the redwoods in the Mangels Ranch Area are in unique cluster
formations. Over the past two years I have conducted a study on the process of this redwood
cluster formation that has not been previously described. The study is still under way and
some of the results are given in the cluster section of the text and in Appendix I.
California State Parks Department Request
In August, 2003, Kirk Lingenfelter, Superintendent of the Central District of Santa
Cruz County State Parks, asked me to present what I considered to be the most valuable use
configuration for the Mangels Ranch Area before it is opened to the public. Mangels Ranch
Area is a unique, nearly primeval area that is highly suitable for development of an
outstandingly rich interpretative nature trail emphasizing redwood adaptations in the southern
sector of its range.
To justify the nature trail, I needed to conduct a thorough literature search on life
histories of the three dominant unique plant species in the area: the redwood, the purple
needlegrass, Nassella pulchra, and the newly accepted subspecies of oak, the Shreve oak,
Quercus parvula var shrevei. Besides the importance of developing a nature trail for the
MRA, this Guide will also supply instructors and docents with the redwood’s adaptations
throughout its range. The instructors can use the Guide to develop their presentations and can
find additional reference information.
A tremendous amount of research has been conducted on the redwood in recent years. Most of
the basic life history studies were conducted in the Northern California heavy rain and fog.
Consequently, there has been less research conducted in the drier part of the range south of
There are adaptations of the redwood in this southern extension that may be valuable
for the species survival as global warming continues. The Mangels Ranch Area not only has
examples of all the adaptations of the northern area redwoods, but also has examples of
redwood adaptations in its drier southern extension. I had not at first considered presenting
this information as a guide, but after intensive study, it became evident that by including the
Mangels Ranch Area redwood adaptations, a Guide could be constructed for interpretive
specialists throughout the redwood’s range. At the turn of the century, the area now known as
The Forest of Nisene Marks State Park was the southernmost region in the state yielding great
quantities of redwood lumber.
This Guide has many quotations and excerpts from the works of key redwood
researchers. I have several reasons for this: (1) Even though I had Forestry research training, I
am relying on many quotes and excerpts from the recent researchers to adequately relate the
latest forestry information that is new to me. I have sufficient education to understand what
they are saying, thus the many quotes and excerpts from the principal research contributors.
When I paraphrase information from a publication, to be safe, I sometimes follow the
paraphrase with the direct quote, (2) the reader does not have to take time to obtain the
publication to question the meaning of a quote, and (3) some quotations present beautifully
worded phrases and personal feelings. These thoughts cannot be transferred into someone
else’s terminology, and should not be used unless quoted. Aldo Leopold’s (Aldo Starker
Leopold’s father) description of the Land Ethic on pages 3-4 of this Guide, is an example of
an elegant, lucid analysis of a philosophical truth.
Several subjects are given a greater number of quotes in the Guide. These include the
difficulty in understanding the differences between lignotubers and burls, the definition of an
old-growth tree, and the fascinating discussions of the MFI (mean fire interval) Regimes by
Greenlee and Langenheim. The Fire Regime data are as much for historical value as they are
for scientific analysis.
Because of the lignotuber’s importance, I have given it extensive quoting. Apparently
most natural history writers and redwood researchers considered there are not enough
physiological differences between burls and lignotubers to mention lignotubers to the general
public, so they discuss burls only. These two redwood growths are complicated but are
important physiological adaptations, and interpretive specialists should be aware of their
The Guide has a glossary which includes scientific subjects and terms in the quotations
and excerpts, as well as from my text. Part of the Guide includes the tentative results of my
continuing research on Slump Jumble Clusters.
I have also followed new wording of some redwood adaptations suggested by some of the
authors, and have added a few of my own suggestions for uniform terminology. These include
the unscientific and misleading use of the term “fairy rings” instead of sprout rings, the
common correct use of sprouts instead of clones, and the meanings of nursery log, nurse tree,
nurse plant, and reiteration. I use the name “Piggyback Tree” for a living downed redwood
with tree-like reiterations growing on the dorsal surface. This uncommon growth adaptation
has been mentioned in the literature, but has not been given a name.
Primary Value of the Guide
The Guide is punched for binders so users can enter new items or replace old data. The
binder can be carried by the instructor, and when encountering a difficult question in the field,
the Guide may include the answer, and the name of an author or book for more information.
Book reviews are included for users to develop their own redwood life history library. The
Guide includes mention, and often extended descriptions, of most of the redwood’s
adaptations to survive from the coastal Northern California rain forest to the chaparral and
Northern Scrub plant communities of central California. The Guide would be of value to CSP
interpretive specialists and docents in all redwood parks. New information of the formation of
redwood clusters that is not in the literature is elaborated. I expect this comprehensive
collection of redwood life history data would attract potential docents and trail volunteers.
Before describing the attributes of the Mangels Ranch Area, I am thanking the Van
Eck and Mangels families for their foresight in preservation of a unique valley in this area that
Agnes and Jan Carel Van Eck named Happy Valley. In about 1918, they joined the Save-the-
Redwoods League, and kept this nearly primeval valley protected. The 2005 revised General
Plan for the Forest of Nisene Marks State Park proposes that the trails in the MRA to not be
multiuse, thus enabling the future development of an exceptional Nature Study trail system for
educators as well as for hikers and runners.
Changes in Cultural Values Regarding the Redwood
The redwood is one of the world’s most esteemed and desired trees for forest
silviculture. Concurrently, ecologists and other concerned persons seek to insure the survival
of the redwood as a major feature of California’s terrestrial vegetation. Virtually uncontrolled
harvesting occurred during the ecologically disastrous days of Manifest Destiny and industrial
growth of the late 1800’s. Far too late, laws were passed to curb unsustainable harvesting
practices, and to protect both the remaining five percent of old-growth redwoods, and second-
growth redwood stands nearing harvesting size.
These days, where second-growth forests are harvested on private land, the forests are
sometimes replaced by plantations - masses of single-aged trees that of themselves do not
constitute natural forests with their associated abutting and understory plants, birds, and
animals. Such artificial plantations do not form natural ecotones with natural plant
communities, but are part of management to supply redwood lumber and products. I do not
know the present status of this harvesting practice. Many environmental activists, either
through private efforts or through organizations, have been effective in altering societal values
and restructuring public policy concerning redwood harvesting to maintain sustainable harvest
yields. They have also brought attention to the esthetical and educational values of
maintaining totally protected areas for wilderness experiences and contemplative enjoyment. .
In 1971, natural history writer Elna Bakker1
in AN ISLAND CALLED CALIFORNIA
described the disappearance throughout the world of most species of Sequoia over the ages,
due to climate changes. Bakker urged that attention be given to retaining the few nearly
primeval forests remaining, and reported the attitudes of some of the harvesters: 1*
Foresters have referred to them as ‘disaster climax forests,’
meaning that if totally protected from the rejuvenating
effects of near calamity the species would sooner or later
suffer the consequences of its vigorous nature and degenerate
under the decadence of soft living.
Harvesters wish to increase tree growth by harvesting the larger trees so that smaller
ones, freed from the shade cast by the older ones, can grow more rapidly. The board-feet yield
of a forest often increases with remaining younger trees. Harvesters also wish to remove trees
that they deem unmarketable - “cull” and “trash” trees. In contrast to this commercial stance,
increasing numbers of ecologically aware persons are at last demanding preservation of all
remaining old-growth trees, and more protection of second-growth forests.
* Throughout the Guide, superscript numbers refer to the author in the
literature Cited section.
The ecological trend of considering the redwood as part of a plant community rather than only
as a harvestable rapidly growing tree appeared in 1977 in the following quotation from one of
the prominent redwood researchers, Paul Zinke2
There needs to be more study of the autecological requirements
of the various species that comprise its forest vegetation. For
example, most of the coniferous forest species are at the
southern limit of their ranges in this portion of California,
representing the southern limit of the great coniferous forest
of the Northwest. Presumably this is related to the greater
aridity and warmer temperatures that occur at this transition
to oak woodlands and grasslands to the south and to the
interior. Are these limits due to occasional extremes of
drought, or to gradients of increasingly limiting average
moisture? At what points in the life cycles of the species
concerned are the factors limiting: is it seedling survival
that is critical, or overall growth in relation to competitive
The Conference on Coast Redwood Forest Ecology and Management was held at
Humboldt State University in 1996. W. J. Libby’s keynote address, expressing the abiding
concerns of ecologists about redwood preservation, called for increased ethical choices. He
expressed the concern about redwood protection, and discussed the value of the lumber
industry to conduct a sustainable yield concept which includes recognition and respect for
Management of our forests should serve various and carefully
considered human goals, ideally these goals will have ethical
underpinnings. Some of these goals will be to a degree,
mutually exclusive. One goal is to grow and harvest redwood as
a renewable alternative to non-renewable, environmentally more
harmful resources. A second goal is to maintain any of the
other species that inhabit redwood ecosystems and particularly
to husband those that have been negatively impacted by human
W. J. Libby3
also asked “Is sustaining biodiversity a human goal?”
The answer is, apparently, yes. Today, more organizations than ever, and more individual
activists direct their efforts toward protection of the environment and ecosystems. At the
Humboldt State conference, Fredrica Bowcutt of the Society for Ecological Restoration in
Mendocino County presented a paper describing interviews conducted with timber workers,
resource ecologists, and reinhabitors (back-to-landers). On the topic of ecological approach of
management, Bowcutt reports:
The reinhabitors and resource ecologists placed high on the
priority list controlling invasive exotic species, landform
restoration (recontouring of abandoned roads), and stream
restoration…. Timber workers are split 50/50 on whether non-
native species should be managed. Part of this can be explained
by the relatively high percentage of timber workers who do not
support any ecological restoration efforts.4
In 2000, Conservation Biologist Reed Noss5
The reader is aware by now that saving the redwoods means much
more than saving big trees. It means protecting the forest
ecosystem in its natural condition wherever such opportunities
exist…. Because some species require management practices are
still unknown…. Sustainability is appropriately interpreted as
a landscape or regional-scale property. It depends on
protected areas (reserves) as well as areas where redwoods are
In the July, 2000 issue of the Journal of Forestry6
, the publication of the Society of
American Foresters, several articles and comments appear about the updated Code of Ethics
for Society members, demonstrating encouraging changes in societal attitudes on ecology. In
the year 2000 Code revision, the preamble included additional concepts to be considered
including Common Morality, Land Ethic, Land Health, Commitment for the Larger Goals of
Society, and Ecocentrism. Included in the year 2000 Preamble were comments referring to
Aldo Leopold’s term “Land Ethic.” I quote from Leopold’s 1949 book, A SAND COUNTY
ALMANAC.7 (pages 202-207)
The extension of ethics, so far studied only by philosophers,
is actually a process in ecological evolution. Its sequences
may be described by ecological as well as in philosophical
terms. An ethic, ecologically, is a limitation on freedom of
action in the struggle for existence. An ethic,
philosophically, is a differentiation
of social from anti-social conduct. These are two definitions
of one thing. -- The land ethic simply enlarges the boundaries
of the community to include soils, waters, plants, and animals
or collectively: the land…. In short, a land ethic changes
the role of Homo sapiens from conqueror of the land community
to plain member and citizen of it. It implies respect for his
fellow-members, and also respect for the community as such.
In his book ROUND RIVER printed four years later in 1953, Aldo Leopold gives this
disquieting reminder to budding ecologists8 (page 165)
One of the penalties of an ecological education is that one
lives alone in a world of wounds. Much of the damage inflicted
on land is quite invisible to laymen. An ecologist must either
harden his shell and make believe that the consequences of
science are none of his business, or he must be the doctor who
sees the marks of death in a community that believes itself
well and does not want to be told otherwise.
Besides Aldo Leopold’s discussion of Land Ethic, other recently coined terms are
appearing in today’s expanded ecological lexicon --- for example, Leslie Reid’s14
can be used instead of “landscape” for vistas of plant communities.
Scope and Format of the Guide
The Guide emphasizes redwood functions as part of an intricate mosaic of plant
communities existing near the southern limit of the redwood’s range. Redwoods in this area
may be key to the survival of the redwood as global warming continues. Its interaction with
other species in the southern limit may reveal physiological adaptations to more relatively dry
and warm climates. Several of the associated plant species may also be near the limits of their
habitat requirements and distribution.
This discussion of the redwood covers all of its range. Examples of certain adaptive
structures are emphasized when they exist in the Mangels Ranch Area (MRA) (Figures 1 and
2). These adaptations will be demonstrated in a proposed nature trail series of interpretive
sites in MRA.
The citation for each publication or paper in the literature-cited section is given in the
text in small superscript numbers at the beginning or end of each quotation (or
Figure 1. Lower Area of the Forest of Nisene Marks State Park Noting the Location of the Mangels
Ranch Area, the Pourroy Trail Area, and the Flat Understory Area of George’s Picnic Area.
Figure 2. Topography and vegetative classification of the Mangels Ranch Area in the Forest of Nisene
Marks State Park.
author’s name) each time it appears. To facilitate gathering additional information, a review
section of the key books and research papers is included.
SECTION I - DEFINING THE ECOSYSTEMS AND TOPOGRAPHY FOR
THE MANGELS RANCH AREA (MRA)
A plant community is an aggregation of living organisms having
mutual relationships among themselves and to their environment.
Munz and Keck 9
Competition in a particular area for the basic needs of plants - nutrients, space, and
light, - results in the plant community for that area. Plant community studies are necessary for
the evaluation of Proper Use trail and nature study sites I will propose for the Mangels Ranch
Area (MRA) and in the Lower Area (Figure 1) of the Forest of Nisene Marks State Park
(FNMSP). In the Guide, I sometimes refer to these proposed sites in discussing and
demonstrating local plant communities.
California ecologists and botanists over the past 30 years have created plant
classifications according to their particular needs. This Guide uses classifications adopted by
the California Native Plant Society, whose project started in 1977 (Terrestrial Vegetation of
California, edited by Michael Barbour and Jack Major, 1988).10
Other naturalist writers with
similar but varying vegetative criteria are Elna Bakker1
, Philip A. Munz9
, Verna R.
, and Allan A. Schoenherr12
Schoenherr listed the large scale California biomes: desert, scrub, grassland, forests,
temperate rain forest, temperate deciduous forest, and tundra. He also listed most of the
vegetative types presented by Munz with some changes. Munz9
listed the vegetative types as:
Strand, Salt Marsh, Freshwater Marsh, Scrub, Coniferous Forest, Mixed Evergreen Forest,
Woodland-Savanna, Chaparral, Grassland, Alpine, and Desert Woodland.
Subsequent to the Munz outline the California Native Plant Society formulated its
system, which includes most of the Munz criteria with minor changes. In Barbour and
, the broader categories are called Floristic Provinces. These provinces are:
Californian, Sierran, Pacific Northwest, Great Basin, Hot Desert, and Southern California
Islands. These six Floristic Provinces contain 20 vegetation types or plant communities.
The Floristic Provinces in MRA and Lower Area of the FNMSP are the Californian
Floristic Province and the Pacific Northwest Floristic Province. The plant
communities of the Californian Province in MRA are Mixed Evergreen Forest, and Oak
Woodland. The plant communities of the Pacific Northwest Province in MRA are Redwood
Forest, Coastal Prairie, and Northern Coastal Scrub.
The species composition of each of these floristic provinces and plant communities
has a basic continuity, with species varying in number and abundance by region. A partial list
of the dominant plant species in the above plant communities for MRA, and the lower area, is
given in the Wildlife Section, pages 78-88. .
Vegetative Climax and Seral Stages
Another criterion for analyzing a forest is to consider how long ago the forest was
logged or burned by a forest fire, and at what stage of climax it is presently in (Schoenherr12
The climax concept is used to define plant communities that have existed for centuries or
longer in a climax condition, that is, when the vegetation has achieved stability and changes
are gradual. Whenever natural catastrophes occur such as fires, landslides, and floods, a
climax area becomes sub-climax for a long period. After a heavy logging, hundreds of years
may pass before a redwood forest begins to regain its classic forest appearance, and hundreds
of years or thousands, to return to climax. A. A. Schoenherr12
relates the importance
ecologists place on the concept of climax communities:
The varied mixture of trees and plants of all sizes and ages
represents “climax community,” the natural balance of
plant species that has been attained over centuries. If left
without intervention or natural catastrophe, such complex
ecosystems will sustain their healthy composition indefinitely.
Examples of climax communities are rare, particularly in such
populous places as California; thus, protection for them is all
the more important, for they are easily accessible displays of
nature in its purest form.
Much of the discussion in this Guide will be about ecosystems and plant communities
and their climax status. To understand the formation process of plant aggregations arriving at
a climax plant community, a review of PLANT ECOLOGY by Weaver and Clements13
instructive. The following information was derived from their textbook.
The Sere. A sere is the long-term process of reaching vegetative climax from the first
stage of habitat conditions and plants to a potential climax status. The climax plant
aggregation is the product of species competition in an area controlled by topography, soil
conditions, and climate.
At the beginning, the status is early-seral, and near climax becomes late-seral. These are
terms that appear in Timber Harvest Plans.
If the sere process starts in a pond or lake it is called a hydrosere. The stages in sere
sequence in a hydrosere leading to a forest climax are: submerged, floating, reed-swamp,
sedge-meadow, woodland, ending with climax forest. The climax process is not completed
until those tree species present which are best suited to the local conditions become dominant
or co-dominant .
If the sere is forming a climax on rockbed, such as a new lava flow, it is called a
xerosere. The successional stages are: crustose-lichen, foliose-lichen, moss, herbaceous,
shrub, ending in a climax forest.
Within a plant community or ecosystem there may be several seral stages of plants due
to minor disturbances of fire, floods, treefalls, land movements, and human activity. The time
scale may be different due to the severity of the disturbance, but each sere contains its own
process to climax. Weaver and Clements explain:
Beginning slowly, increasing to a maximum, and then gradually
receding, the plant populations of each have made conditions
fit for the next community but often less fit for their own
continuation. 13 (page 71)
In the Mangels Ranch Area, the upper canopy dominance is primarily Shreve oak,
Quercus parvula var shrevei, and/or redwood. Other tree species are present, but do not
become dominant. These are: coast live oak, Quercus agrifolia, Douglas-fir, Pseudotsuga
menziesii, Pacific madrone, Arbutus menziesii, California bay, Umbellularia californica, and a
scattering of western sycamore, Platanus racemosa, arroyo willow, Salix lasiolepis, and big-
leaf maple, Acer macrophyllum. The tanoak, Lithocarpus densifolia, occurs only in the
riparian area of the MRA, apparently the Happy Valley area of MRA (Figure 2) is too dry for
this more mesic plant. The riparian corridor along Mangels Creek does not contain red alder,
Alnus rubra, which is the co-dominant species with big-leaf maple in the riparian area of
Topography, Geology, and Climate
Vegetation in a given area is the result of topography, soil conditions, and climate. In
the MRA, the transcending climate conditions for redwoods are coolness and high air
humidity, and deep valley protection from strong drying winds. In this southern extension of
redwood distribution in California, drought becomes a major factor of survival. The redwood
can survive in areas of occasional light snowfall.
If one were reconstructing climate from stand characteristics
one might infer that drought is more ‘normal’ than the average
is. (L. Reid 14
Slope dynamics is strongly operative not only in redwood distribution, but for all plant
communities in California coastal ranges where Mediterranean climate prevails.
Edaphic slope orientation to the sun interacts strongly with temperature, humidity, and storms.
Vegetation in a Mediterranean climate, with its long, hot summer, is restricted, especially on
the southward facing slopes which are cloaked with drought-resistant vegetation. In the
MRA’s Happy Valley, the same factors are present, but are at a 90 degree directional
difference because the ridges forming the valley run in a north-south direction. The sun’s rays
increase the drought species on the west-facing slopes which receive the afternoon’s drier air
(fog usually is dissipated by noon) and stronger winds and sun’s rays. The greater dryness of
the west-facing slope in MRA is adverse to most west-facing slope conditions elsewhere in
the redwood range. The following discussion of the slopes in the MRA demonstrates the
strong influence exerted by local climates and topography upon the redwood and associated
East- and West-facing Slopes of The Mangels Ranch Area
The area consists of two virtually north-south oriented ridges - Hawk Point Ridge and
Monte Toyon Ridge (Figure 2). Certain basic climatological and topographical factors have
created three divergent mosaics of plant communities in spite of the fact that they each have
the same rainfall, similar soil conditions, and steepness of slope. The floor of Happy Valley
lies about 200 feet below the ridges. The two steep slopes forming Happy Valley are the west-
facing slope of Monte Toyon Ridge, and the east-facing slope of Hawk Point Ridge (Figure
East-facing Slope of Hawk Point Ridge
Plant growth on the Hawk Point Ridge east-facing slope is dominantly redwood
clusters intermixed with Shreve oak, Douglas-fir, big-leaf maple, California bay, and patches
of Northern Coastal Scrub. During morning hours until about 10 am to 1 pm, the usual fog
concentration blocks the direct rays of the sun rising over Monte Toyon Ridge, allowing the
Hawk Point Ridge east-facing slope to remain cool.
In the afternoon, the sun’s rays do not directly hit this slope. Therefore, the slope
remains cool and moist throughout most of the days of the year because of the topography,
and also because of the presence of over 600 redwood trees which enhance their own cool and
The redwoods on this slope form clusters in which there is little or no vegetation between the
peripheral old-growth trees (see details of cluster formation on pages 62-78).
West-facing Slope of Monte Toyon Ridge
The west facing slope of Monte Toyon Ridge does not receive the sun’s rays until late
morning, and when foggy, is even more cooled. When there is no fog in the afternoon, the
slope receives the afternoon’s direct sun on clear days. The afternoon climate also includes the
drying northwest winds which increase excessive transpiration of all vegetation. This is most
likely why there are no clusters of redwoods on this slope, but only a few scattered redwoods
along with big-leaf maples, both needing to be cool and moist. This west-facing slope has an
almost contiguous canopy of Shreve oak. When large trees fall, seeds of the other plants in the
area can take advantage of the mineral soil exposed in the gaps to receive more sky light and
Southwest-facing Slope of Hawk Point Ridge
Hawk Point Ridge’s southwest-facing slope is steep near the ridge top, but becomes a
more gradual slope when nearing Aptos Creek road (Figure 2). It receives more direct sun and
wind than the slopes inside Happy Valley. The southwest-faced slope on Hawk Point Ridge is
not shadowed in the late afternoon by another close high ridge to the west and receives nearly
full afternoon sunlight and stronger drying north-west winds. The climate conditions on this
more exposed slope favor prairie and scrub plant communities.
Coastal Prairie and Northern Coastal Scrub occupy the lower part of the slope
along with an Oak Woodland of mixed Shreve oak and coast live oak on the upper slope. In
the oak woodland, an almost evenly mixed canopy of oaks is formed, with a few Douglas-firs
mixed in on the upper reaches of this dryer slope. Scrub species border and mix in the
ecotones with the oak woodland and purple needlegrass forming a diverse plant mosaic.
The more common grass and scrub species are purple needlegrass, Nassella pulchra;
Coyote brush, Baccharis pilularis; sticky monkeyflower, Mimulus aurantiacus; California
sagebrush, Artemisia californica; California blackberry, Rubus ursinus; poison oak,
Toxicodendron diversilobum; and bracken, Pteridium equilum.
Several clusters of redwoods on this slope are in east-west oriented gullies having
north-facing slopes. These clusters are redwood stand clusters (see page 62) that do not
create a vacuity of non-growth in the center as in slump jumble clusters in Happy Valley
(see below and 69-71). One stand cluster (Figure 2 E) is in a gully that supports 150 trees.
There are two more stand clusters on the borderline between MRA and state property obtained
before the MRA addition (Figure 2 D).
Soils are the product of the bedrock acted upon by chemical and physical erosion and
vegetation. There are two government soils publications for Santa Cruz County.16,17
show what is evident to the eye, that Happy Valley soils are different than other soils in MRA
and the Lower park area of the FNMSP.
On a map in a soils publication (Raymond Storie, et. al, 1944 16
), the Happy Valley
area is distinctly outlined, with the soil borders located directly along the Hawk Point and
Monte Toyon ridges. The soil type is Steep Hugo Loam which appears in FNMSP in the
Happy Valley area, partly in the Pourroy acquisition (Figure 1), and one small area in the
upper park. It is a highly erodable soil found on steep slopes.
The 1980 publication (Roy Bowman et. al, 17
) is more definitive for commercial and
recreational uses. The soil type in Happy Valley follows the same ridge lines of Hawk Point
and Monte Toyon ridges as in the 1944 study, but is labeled “112” which is not present
elsewhere in the park (Figure 3). They call “112,” a form of Ben Lomond loam on which: 17
Runoff is rapid to very rapid, and the hazard of erosion is
high to very high.
The 1980 publication reported that this soil type is suited for redwood and Douglas-fir
harvesting, but is not good for camping and picnicking because of its “severe steep” soil
category. This publication reported slopes up to 75% in Happy Valley. Some areas on the
east-facing slope of Hawk Point ridge are sheer cliffs, dripping with water.
Floods, Landslides, and Slump Jumbles
(including slump jumbles), and washouts are important for
plant reproduction of a climax woodland area. Because of the narrow steep sided canyons of
the FNMSP there are no flat alluvial stands that are common in the northern California
redwood area. Fires can clear away vegetation and dying material over mineral soil which
most seedlings need for the tender roots to become established. Fires are rare in MRA, and
seedling reproduction of redwoods and a few other trees species is almost non-existent
without exposed soil from a landslide scar, slump jumble, or root-pull pits and rootwads
formed by uprooted downed trees. As will be described below, redwoods can reproduce
without seedlings by dormant buds sprouting from stump roots, lignotubers, burls, buried
branches, and cuttings.
Figure 3. Soil types in the lower area of Nisene Marks State Park, with emphasis on the highly
erodable Ben Lomond loam extending through Happy Valley to near the Mangels-Van Eck Redwood
in the Mangels Ranch Area. The loam is labeled #112, and is enhanced in this copy. Map from
Bowman, 1980. 13
SUMMARY OF REDWOOD STRUCTURES AND ADAPTATIONS
The Redwood as a Superlative Tree
First, let’s settle three potential problems: the height of a downed Eucalyptus tree in
Australia that was taller than any redwood has not been verified19
, and, the Redwood’s Sierra
Nevada foothills cousin, Sequoiadendron giganteum, is uniformly called the Giant Sequoia,
but Sequoia sempervirens may have two common names.
Is the Official Common Name REDWOOD or COAST REDWOOD?
If one follows the taxonomists and field identification authors, the common name is
Redwood for Sequoia sempervirens. The following publications using redwood only are:
Jepson’s original MANUAL OF THE FLOWERING PLANTS OF CALIFORNIA, 1923, Hickman’s18
revision of Jepson’s Manual, 1993, Barbour and Major,10
1988, and Lanner,19
History writer Verna Johnston,11
1994 also uses redwood throughout, except to say one place
in the book that the redwood is also called the Coast Redwood, and does not include the Giant
Most natural history writers and some researchers use both Coast Redwood and
Redwood, These include Noss5
, 2000, Evarts and Popper24
, 2001, Richard Rasp54
, 1989, and
John LeBlanc, editor of the Proceedings of the 1996 Conference on Coast Redwood Forest
Ecology & Management at Humboldt State University. Of the participants in the 1996
conference at Humboldt State University who submitted papers giving the common name, 30
used redwood only, and 14 used both coast redwood and redwood.
In the natural history and research publications, coast redwood is often used in titles
and some headings, but the tree is referred to as the redwood throughout the rest of the text. I
am following this style in the Guide. To call it “coast redwood” at all times would be a burden
to the reader and writer. I picked 20 pages of text at random in Reed Noss’s book, and
computed that redwood by itself appeared about 1800 times in this publication. In this Guide,
the official common name of “Coastal Redwood” is used in the title, but “Redwood” is used
throughout the text.
The Public’s Imagery of the Redwood
W. J. Libby3
points out that to many people the redwood has an inspirational imagery:
... the substantial volume of poetry about redwoods tends to be
reverential, even mystical.
What creates some of the inspirational imagery, is that the redwood self- prunes
its lower branches when shaded by an upper canopy layer. In a mature redwood forest, self
pruning reveals to the viewer the bottom 50 to 150 feet of huge old-growth trees with bare
trunks and deeply rutted outer bark topped with a thick mass of blue-green needles. The
branches of the oldest redwoods are typically strongly drooping or recurvate, hanging nearly
vertical on some giants (Figure 4.7).
Often only a scattering of understory plants grows in the densely canopied old-growth
areas. These relatively small plants enhance the unique imagery of the over-powering
appearance of the bared lower trunks of the redwood giants.
Official State Trees
The legislature, in separate bills, has listed two official trees for California: the Giant
Sequoia in the Sierra Nevada, and the Coast Redwood (Schoenherr59
The Tallest Tree in the World
In most of the literature, the tallest tree in the world is the National Geographic Tree
redwood which measured 367.8 feet 12,19,54
in 1963. It is on the wind protected alluvial plane
of Redwood Creek in Redwood National Park.
But, there is confusion and uncertainty which redwood tree is tallest tree in recent
literature. I contacted interpretive specialist James Wheeler of the Redwood National Park and
Dave Stockton at the Humboldt Redwoods State Park natural history center. In August 2004,
they reported there are several redwoods in excess of 369 feet. Two giants are near 370 ft. in
Redwood National Park, and two also nearing 370 ft. in Humboldt Redwoods State Park, 60
miles to the south.
Each tree is growing at a different rate, resulting in occasional changes of the tallest
tree. To complicate matters, a giant tree in Redwoods National Park is nearing the height race,
increasing at a rate of about five feet per year.
The tallest redwood in August, 2005, is the Stratosphere Giant, in Humboldt
Redwoods State Park at 370.2 feet (Preston64-p225
). In August 2004, measurements determined
that the Federation Tree in the Humboldt Redwoods State Park, in Founders Grove, was at
369.2 feet. Founders Grove is where the 360 foot Dyerville Giant fell in 1991.55
National Geographic Tree in Redwood National Park was at 369.0 feet, and the Mendocino
Tree in Humboldt Redwoods State Park was 368.0 feet tall. The heights are measured by
climbing the trees by Dr. Steve Sillett and crew from Humboldt State University.24, 64
Maximum Diameters of the Redwood and Giant Sequoia
includes a table listing the heights and diameters of 40 large redwoods on
public property throughout the range of the redwood. Twenty-six of the trees were over 325
feet in height, and 15 trees had diameters over 20 feet. The redwood is the second widest tree
at 25.8 feet5
dbh (diameter-at-breast-height), surpassed only by the Giant Sequoia at 37.5
The redwood is the fastest growing tree22
, and is among the highest for yield of wood
in the world. The redwood has shown good growth in many places in the world, but extensive
redwood forests have not been established in other countries.23
Maximum Ages of the Redwood and Other Very Old Trees and Plants
The redwood reaches at least 2200 years of age. It is surpassed in longevity by
the Giant Sequoia at near 3300 years (Lanner19
), the western bristlecone pine, Pinus longaeva
at 4862 years (Lanner19
), and the desert dwelling creosote bush, Larrea tridentata, 18,000
Other superlatives are that (1), the redwood’s bark is thick and contains only a trace of
oils, making the large trees almost fireproof (2), redwoods reproduce by both seedlings and
sprouts (3), a large percentage of the redwood’s annual water supply in some areas comes
from fog drip off its branchlets falling to the ground to be absorbed by the roots, and (4),
mentions that redwood killing diseases are rare, and appear to not die of old age.
The redwood is also genetically unique. Noss:5
Redwood is unusual among conifers in being hexaploid…. It has
66 chromosomes ... whereas most conifers have from 20 to 24.
Because redwood is hexaploid, it is possible to have much
allelic variation within a single individual (i.e. alleles are
alternative forms of the same gene.) ... In short, redwoods
have enormous within-family genetic variability, and we now
have the tools to find and characterize it.
Basic Redwood Structures and Adaptations
Ecologists need to identify the physical structures of the redwood which have
survived many catastrophes of severe climate and wildland fire changes along our coast.
Redwood concentrations had already changed considerably under prehistoric conditions, and,
because of its high economic value, the survival of healthy stands of old-growth forest has
been constantly threatened by human activity. The structures and adaptations the redwood has
developed will be described in the text below and depicted in Figures 4.1 - 4.17, and in
Appendix II. These drawings, not always in sequence as they appeared in the text, are
grouped together here to facilitate finding them when reading the text.
Figure 4.1 Seeds and needles of the redwood, Sequoia sempervirens
Figure 4.2. THE OMEGA REDWOOD. This Residual Old-Growth redwood is one of the few remaining
old-growth trees that were not harvested in the George’s Flat area. It is called THE OMEGA
REDWOOD because nearly all the possible growth structures of a redwood are present on and around
Figure 4.3 The Piggyback Redwood Nurse Tree in One of the Clusters (Figure 6, p. 63).
A dying tree (A) near the center of the cluster is probably from a dormant bud in a lignotuber in the
rootwad (B). Sprouts or seedlings are not growing in the root-pull pit (C). The reiterations on the fallen
trunk receive their energy and water from its remaining viable roots (D). These roots are also
contributing energy for the continuing increased size on the treefall trunk as evidenced by the sharp
decline in trunk diameter after each reiteration. The trunk is embedded slightly into the soil in two
sections (E and F), but no roots are entering the ground from the trunk in those areas. In tree species
that have piggyback growth, the trunks must have a viable root system to supply water and energy to
reiterations. The plants in the foreground (G) are bracken, wood fern, and coffeeberry. The understory
area is covered with redwood branchlet litter, and is within the shading influence of surrounding trees.
The large tree (H) is the second largest tree (46 inches dbh) in the cluster. It and the other 13 old-
growth redwoods in the cluster are strongly influencing the growth of the reiterations through
competition for direct sun and sky light, food, and water. This slump jumble cluster (Figure 6) was
formed around 400 to 500 years ago.
The cambium layer is one cell thick. Cambium
cells continually divide, but at higher rates in
summer for reproductive energy and tree
growth. Each cambium cell forms daughter
cells that create the vascular and cork
Outer Bark. As in the heartwood, tannins and
other phenolics resist pathogenic fungus and
bacteria that enter through fire scars, injury,
and insect damage. Cork cells dominate,
forming rings of alternate growth with other
types of cells. Alternate rings of cork cells and
other cells are laid down annually, but cannot
be used in growth studies. This section of bark
has only eight rings in an area with 50 rings in
the xylem. As in the phloem, the redwood
outer bark has dense fibers. Resinous and
volatile compounds are minimal in the outer
bark, giving fire protection to the tree.
Phloem or Inner Bark. The cells in this layer
are not wood cells. They are living fibrous cells
that transport sugars and other organic
compounds to all parts of the tree for growth
and sustenance. Annual rings are not made in
this layer. The fluid movement is down the
trunk as well as laterally along the limbs and
branchlets. The fibers are highly distinctive in
a cross section of the trunk.
Xylem or Sapwood. These living wood cells
give strength to the bole and transport water
and minerals from the roots to the entire tree
by osmosis. Storage of water also occurs in
this layer. Annual growth rings are formed in
the xylem. The early fast growth occurs in
early spring, and an annual ring is formed at
the end of the late growth period in fall and
Heartwood. The heartwood is dark red due to
concentrations of tannins that are a type of
phenol. The cells are dead sapwood cells that
become hardened and change in color and
form when carbohydrates are no longer
available to the cells abutting the xylem. The
heartwood and roots can succumb to fungal
infections when the bark is removed by injury
or fires, often resulting in fire scars and
Figure 4.4. Cross section of a 25-inch dbh redwood at 8.4 feet above the ground describing the
functions of cells in the cork and vascular cambium layers. (Results of further study of this tree’s
growth reveals possible reactions of the tree due to increased rainfall, groundwater quality, and light.
See Appendix II.)
Figure 4.15. Key identification features of the Coast Live Oak and Shreve oak. Leaves and acorns are
50% of actual size. The above differences are not always definite, but if at least five acorns or leaves
are inspected from a tree, identification would be reliable. (A hybrid of these species may not be
identified by these criteria).
Nursery Log. This is a 22 foot section of an over 100 feet long decomposed Douglas-fir nursery log. It
lies mostly under the canopy of a large big-leaf maple. California coffeeberry is the dominant plant on
the log. The redwood seedlings appeared about 12 years ago. Other species on the log are big-leaf
maple seedlings, common chickweed, narrow leaf miner’s lettuce, California figwort, bitter-cress, the
fern Polypodium calirhiza, and mosses. The chain fern is rooted under the log.
Figure 4.17. The healing process is shown of a redwood buttress injury in 1982 when the tree was 23
years old and had a diameter of 7.3 inches of vascular cambium. The deposition of vascular and cork
layers are shown at six heights of the bole. The tree was 61 years of age, with a height of over 80 feet.
Forests, Stands, and Groves
A redwood forest is forest in which redwoods are the dominant canopy species.
Treefall gaps and occasional landslides and slump jumble scars, fires, etc., appear in climax
forests creating sites where seedlings of all species present can grow and compete, thus
sustaining a diverse forest structure. Redwoods usually form abrupt mixed ecosystem mosaics
when abutting other distinct plant communities.
In an uneven-aged old-growth stand, redwoods are distributed throughout the stand
with varying degrees of isolation and spacing. This somewhat random and uneven spacing is
caused by varying topographic and geological structures and competitive plant dominance for
space and sun. The redwoods with self-pruned lower bare trunks often have nearly contiguous
canopies including an occasional sub-dominant tree species. Considerable variation in
understory species and abundance occurs in different local physical habitats, and also by
A thick forest of giants is the public’s stereotype of a redwood forest. Splendid
photographs of these old-growth giants are given in an oversized publication Redwoods by
Jeremy Joan Hewes20
, and in Evarts and Popper’s24
In deeply shaded areas, redwood seedlings have an advantage over the seedlings of
other tree species. Tanoaks (and to a lesser degree Shreve oaks) are also shade tolerant and
may be dominant over young redwood trees for a short time, inhibiting redwood reproduction.
Eventually, the much faster growing post-sapling redwoods prevail over tanoak competition.
In the silvicultural harvesting method of small-area clearcut plantations, tanoaks are thinned
out, or poisoned.33
A stand is a concentration of trees in a particular location, such as stands of redwoods
on a slope may be different than redwood stands in flat areas. “Stand” is
often used in silviculture discussions.
The term grove of redwoods is usually applied to a special concentration of trees such
as the famed Richardson Grove along Hwy 101 in Humboldt County. In the Lower Area of
FNMSP are the Tillman Memorial Grove and the Jan Carel and Agnes Van Eck Memorial
Treefall Gap, Root-pull Pit, and Rootwad11, 25
(Figs. 6 and 7)
A treefall gap occurs when a treefall creates an opening in a forest canopy. Treefalls
are also called windfalls, blowdowns, and wind-throw, fallen, and downed trees. “Treefall” is
the name used by most writers because not all trees are downed by winds. A tree can also be
dislodged by undercutting erosion by floods and landslides. Locally, oak trees have been
weighted down by climbing English Ivy, Hedera helix.
In the Mangels Ranch Area, this ivy has been removed from nearly all the trees, including
redwoods in the MRA.
If a treefall gap is formed by a tree that broke off and the roots are not affected, soil
may not become accessible for seedling reproduction. However, growth of previously shaded
trees may be enhanced if increased light is available to them. Canopy gaps are part of the
redwood reproduction process. Changes in shading and wind protection will present
opportunities for all the species present to compete.
When the mineral soil has been exposed by an uprooted downed tree, seedlings can
take hold either in the root-pull pit25
or the rootwad24
soil. Exposed soil for seed
reproduction is necessary for vegetation which does not reproduce from sprouting after a fire
or other disturbance. In this area, redwood, tanoaks, California bay and many of the
understory shrubs sprout from dormant buds. Sugihara25
reveals the importance of the treefall
gap in forest ecology:
Fallen trees form an important structural part of the stand due
to the great size and longevity of the logs. Through gap
dynamics the redwood forest continuously renews itself while
maintaining massive tree size, high density, and structural and
At first, the process of sere development resulting from a catastrophic event is
competition of the pioneer species26
which can be an assemblage of native species. In the
FNMSP area, aggressive introduced species18
such as Australian fireweed, Erechtites minima;
English ivy; Cape Ivy, Delairea odorata; French broom, Genista monspessulana; and prickly
clover, Trifolium angustifolium are highly invasive.
Some introduced species do not need a treefall gap to establish themselves. Dirt road
or trail construction almost always results in invasive plant establishment in MRA, especially
by the four species mentioned above, along with the forget-me-not, Myosotis latifolia, and
several species of annual grasses introduced from the Mediterranean area.
Harvesting Effects - Percent Remaining of Old-growth Redwoods
Lawrence Fox III27
reported on the degree of removal of old-growth forests:
In 1989, old-growth forest comprised ten percent (207,000
acres) of the land area. The largest and most dense old-growth
redwood occurred on four percent of the natural range. Second-
growth redwood forest classes occurred on 63 percent of the
natural range. Second-growth forests dominated by Douglas-fir
and hardwood species comprised 13 percent of the natural range.
In 2000, Noss5
reported that 93-95 percent of the existing redwood forest on the west
coast is second-growth and third-growth.
Definition of an Old-growth Redwood Tree
In 1998 when attending Timber Harvest Plan hearings, the definition was quite
simple in discussions with timber harvesters and foresters. The definitions of old growth were
those of the California Department of Forestry (CDF) rangers and timber workers who were
complying with the restrictions of the Z’berg-Nejedly Forest Practice Act of 1973. Most of the
research on redwoods has been conducted in the Pacific Northwest coastal area, and at times
the growth patterns and associated species of the redwoods in the northern part of the state are
not the same as in the southern zones, including some areas in Santa Cruz County.
A large old-growth redwood has diagnostic shapes including long strongly drooping
branches, mostly bare lower trunks from self-pruning, and thick coarsely grooved bark. The
main requirement in the northwest heavily logged areas has been for a tree to be around 200
years old. The average size at that age is around 40 inches dbh (see next page) in that area.
Today’s definitions are much more complex and subject to describing the forest, not
just isolated stems. Noss5 (page 87)
For conservationists to evaluate the ability of management
options to meet the needs of species associated with old-growth
redwoods, some understanding of the specific habitat
requirements of the species is desirable, as well as a general
understanding of the characteristics of the old-growth forest.
There is no generally accepted or universally applicable
definition of old-growth ... specifying exact age ranges for
late-successional and old-growth forests is impossible because
of variations in climate, soil quality, disturbances, and
numerous other factors.
The USDA Northwest Forest Plan perpetuates the confusion. Tuchman et. al.28
... as a general rule, late-successional (late-seral) forest as
those with trees at least 80 years old and old-growth forest as
a ‘subset of late-successional forest with trees 200 years or
One of the more clear forest harvesting conditions for determining an old-growth tree
is a forest area which has never been logged. The trees represent a large range of sizes because
of the differences in growth rates in response to topography, soil fertility, light, and
atmospheric and soil water content.
In the Mangels Ranch Area, the average size of a 200 year old tree is around 32 inches
dbh, with a wide range of sizes at that age. One can utilize the official size/age criteria for a
mature redwood, and state that all trees in the MRA over 24 inches in dbh are old-growth.
But, in a residual forest (one that has been logged but with large old-growth trees remaining)
it is difficult to determine whether 30 or 40 year old tree is a slow growing old-growth tree or
a fast-growing second-growth tree. A fast growing second-growth tree could be as large as a
slow growing old-growth tree. The shape of the tree is significant because redwoods change
branch structure with age. On a young tree, the branches extend outward, sometimes bending
upward at the tips (Fig. 4.6). On very old trees, the branches droop strongly downward (Fig.
4.7). For more information, Noss5
has a detailed account of the criteria for an old-growth tree.
Forestry Criteria by Extent of Logging
Unlogged Old-growth Forests - (First Generation Redwoods)
From 1883 to 1923, nearly all the old-growth FNMSP forest redwoods were harvested.
The only unlogged old-growth forest in FNMSP is in Happy Valley where there are more
than 600 unlogged redwoods over two inches in diameter, covering about 60 acres. Except for
30 isolated redwoods, the redwoods in Happy Valley are concentrated in 33 clusters on the
east-facing slope of Hawk Point Ridge. Each cluster has a contiguous canopy of redwood
branches and needles with very little or no understory vegetation in the center. About 60
percent of the trees are old-growth using old-growth limb shape and bark features, and an
approximate age of 200+ years using dbh trunk diameters over 31 inches in diameter.
Diameter-at-breast-height (dbh) is 4.5 feet from the ground level. It is measured by
using calipers, electronic instruments, or by dividing the circumference by pi (3.14159) for
diameter (girth or width).
The distance of 4.5 feet from the ground for a dbh measurement is to avoid the expanding
buttress of a redwood (Figs. 4.2 and 4.17) which may vary considerably by size and age of the
tree. Also, if the tree has developed a large thick burl at the base near the ground, the burl
would exaggerate the volume of the tree when calculating the board feet of lumber.
The east-facing slope of Hawk Point Ridge (Figure 2), is a Redwood-Mixed
climax forest dominated by redwood in clusters. Except for two clusters that
were logged, the redwood cluster areas and associated plants are at late seral and climax. No
recent natural changes in the vegetation due to fires and land movement have been observed.
Treefalls of two Douglas-firs, four redwoods, twelve Shreve oaks, and one Pacific madrone
were recorded in the past six years on this slope.
Residual is used to identify a stand of redwoods that has been logged but has old-
growth trees remaining. The number of old-growth trees contributing to the remaining canopy
determines whether it is called a residual old growth or residual second growth forest.
Residual Old-growth Forest
This term applies to a forest in which there was a minimal selective cut of trees,
leaving a predominantly old-growth canopy.
Marcel’s Forest in the Pourroy property acquisition is an example of a residual old-
growth forest. This stand of forest was logged many years ago but later than the Loma Prieta
period. About 300 redwoods remain, many of them old-growth. The Pourroy acquisition could
be classified as mostly mid-seral with areas approaching late-seral where old-growth trees
dominate the canopy.
The Advocate Tree is in Marcels Forest near Aptos Creek. It has the greatest diameter
of redwoods in the park with 11.6 feet dbh. However, the official definition of dbh possibly
becomes too restrictive in describing the totality of this tree for purposes other than
harvesting. The dbh is officially measured from the uphill or “topside”. If the measurement of
The Advocate Tree circumference is made on the topside or uphill side, the dbh is 11.6 feet. If
the diameter could be measured at dbh from the lower or downhill side, it’s width would be
13.2 feet. The latter measurement gives a more realistic size of the tree, but it cannot be used
to compare its diameter with another tree. If measured at the ground, it is over 14 feet in
diameter. The second widest tree in the Lower Area of FNMSP is the Mangels-Van Eck
Redwood at 11.2 feet dbh (Figure 2).
Residual Second-growth Redwood Forest
If the cut was heavy, leaving only scattered old-growth trees, and their canopy is not
contiguous over much of the stand, the forest becomes residual second-growth. It is residual
because a few old-growth trees are present.
A residual second-growth forest stand with a few old-growth trees is along the
Mangels creek riparian trail in the MRA (Figure 2). This area contains the Mangels-Van Eck
Redwood. Most of this area is probably early-seral because there was a timber harvesting
about 60-80 years later than the Loma Prieta cutting.
Other possible residual second-growth clusters in MRA are on the border with
previously owned state property (Figure 2, D). These are logged stand clusters, but there may
be a few old-growth trees to call them residual second-growth stands.
Second-Growth Forest - (Second Generation Redwoods)
Nearly all the areas logged during the Loma Prieta lumbering period from 1880-1930
in what is now the FNMSP, were clearcut. Massive sprouting with some seedling
reproduction has resulted in an almost even-aged second-growth forest. With additional young
trees entering the stand each year, the logged areas of the forest are tending slowly toward an
The Loma Prieta clearcut operation also entailed removal of non-harvestable
redwoods (termed trash or culls), and most of the broadleaf evergreens such as Pacific
madrone, tanoak, coast live oak, and Shreve oak.
Today, if the harvest is a clearcut, the returning trees at first form an even-aged forest.
After a clearcut operation, when two-year old nursery redwoods are planted and competitive
trees such as tanoak are removed or killed by spraying, the stand is called a plantation, or
A second-growth redwood stand in MRA of about 150 redwoods that has been logged
is on the west-facing slope of Hawk Point ridge (Figure 2, E). It is on the north-facing side of
a gully. Two of the clusters on the top of Hawk Point ridge were clearcut and are now second-
Third-growth Forest - (Third Generation Redwoods)
Second-growth harvesting has taken place in the Lower Area of the park.
A large zone of second-growth in the Lower Area from the steel bridge to the kiosk, was cut
again in the early 1960’s, resulting in a third-growth forest. The owners of the Lower Area
harvested second-growth redwoods west of Aptos Creek from the steel bridge (Figure 1) to
about the southern trail head of the Terrace trail at Aptos creek, and on the east side of the
creek near the kiosk.
Many young redwood clones are sprouting on and around the newer stumps that are
intermixed with highly degenerated at least 80-100 year old stumps of the Loma Prieta period.
Since many of the Loma Prieta second-growth trees were not cut and with more third-growth
young sprouts surviving, the present forest is uneven-aged.
Redwood Distribution - Past and Present
Redwoods originated during the Age of Dinosaurs: Johnston11
Fossils indicate that one hundred million years ago Redwoods of
a dozen species spread widely over western North America,
Europe, and Asia in a climate much milder than today’s. Ice
ages, volcanic eruptions, uplifts of mountain ranges,
continental drift, and drastic climate changes all took their
toll on population survival over the millennia.11
In all the world, only three Genera and species of “redwoods” remain: the Dawn
Redwood, Metasequoia glyptostroboides of Asia, the Coast Redwood, Sequoia sempervirens,
and Giant Sequoia, Sequoiadendron giganteum.5, 9,11, 20
The climatic conditions for the redwood restricts it to the moist maritime climate of
the central and northern California coast. The redwood’s range extends 15 miles into Oregon,
in the Chetco River drainage, Curry County, and south to Salmon Creek in Monterey County
near the San Luis Obispo county line.35
It extends east up to 45 miles from the coast in the
northern section, forming a band of redwoods from 6 to 30 miles wide.3
Due to warmer and
drier climate to the south, the redwood remains primarily in deep canyons south of Monterey.
There are pockets of large redwood trees in the Big Sur canyon areas south of Monterey.
Sea Salt Desiccation
Needle desiccation and tree mortality can occur to redwoods by ocean winds near the
shore. Dehydration of the needles is caused by sea salt aerosol containing sodium,
magnesium, sulfur, and boron.2, 36
FNMSP is apparently beyond the negative influence of
this aerosol. Viers also points out that sea salts can dehydrate and kill redwood seedlings.21
concludes that Pleistocene climate changes have “ended seed production”.
This may not be entirely so, but without sprouts from dormant basal buds, the redwood is at a
great disadvantage in competition with other plants unless floods, landslides, treefall gaps, and
low intensity fires occur creating areas where redwood seedlings can survive.
The branchlets (Figure 4.1) contain rows of needles on the sides. There are two forms of
needles, the flat spreading needles of the lower branches, and the short stiff pointed needles
near the crown. The crown needles, which can be seen on the ground after a strong wind, are
exposed to full sun and drying winds, and are structured to reduce transpiration.
The reproductive branchlets remain on the limbs for three to five years until they
become shaded by new branchlet growth. However, in full sunlight with little shading,
individual branchlets can remain on a limb for up to 15-20 years.24
In autumn, these bright
yellow-orange branchlets make up the colorful surface litter of the redwood forest floor.
Evarts and Popper24
explain the reproductive structures. The:
...redwood is monoecious, which means that male and female
reproductive parts are present on the same plant. Pollen cones
(male) and ovulate cones (female) are borne on the tips of
different branches. (During) ... October-March the male
conelets release streams of pollen. As the pollen grains drift
and descend through the canopy, some settle in female conelets.
... Fertilization takes place about four to eight weeks later.
Redwood female cones mature through the summer, and by mid-winter start shedding
their seeds as the next generation of female cones are being fertilized (Figure 4.1).
studied a mature redwood tree which produced 1000-1500 cones annually,
each conelet containing from 16-26 scales totaling 60-180 seeds (Figure 4.1). This calculates
to at least 1,000,000 seeds for this large mature tree. This sounds very impressive and seems
to represent a high reproductive rate, but redwoods have a very low germination rate because
of pathogenic fungi present in the seed cones. In Mendocino County, there was an average of
only 13% of sound (able to be fertilized) seeds, and in Humboldt county, mature trees
averaged only about 20% sound seeds. Nevertheless, Ronald Lanner19
If trees could think, redwood would probably be described as
having an un-quenchable will to live. Even relatively young
trees bear abundant crops of tiny, pollen-bearing male cones,
and small, semi-woody seed cones.
Survival of Seedlings
Fertilization is initiated in December-January on warmer clear days between storms.
Nevertheless, pollen grains will rupture and be destroyed upon contact with moisture. Pollen
shedding is repeated several times during the winter. Dropped conelets often have sprouting
seeds within the scales.37
When the tree is under physiological stress it will produce large
quantities of heavy seed. After the heavy flooding in 1964, a high survival of seedlings
occurred, with germination rates increasing from a normal of 1.01% to 8.95%.37
After the 1964 flood, masses of seedlings appeared which in places resembled a
“lawn” surface, but very few of them survived due to poor light conditions, root com-petition,
and soil moisture stress. Where there is deep duff, pathogenic fungi contributes to mortality of
seedlings called damping-off. Noss5
lists 319 species and subspecies of fungi associated
with the redwood, twenty of which are pathogenic. Here is Becking’s conclusion on the
success of seedling reproduction:
From the millions of established seedlings only one might
become a giant tree upon severe selection, by luck and chance.37
Tannins and Phenolics
Tannins are a higher molecular form of phenol. Several of these anti-pathogen
substances protect the wood of the redwood from fungal and insect attacks. At the time of the
development of the archegonia, in an attempt to counter destruction of seeds by pathogens, the
tree will produce higher levels of phenolic crystals that kill the pathogens.24
Mycorrhizae are of different forms of fungi in the duff, humus, and soil that are
essential to the redwood and other plants.5
Strands of these fungi invade the radical or
growing tip of the root, assisting the plant in absorbing nutrients from the soil. Redwood root
radicals do not have root hairs.
Determining the Age of a Redwood
Aging is done by counting annual rings on stumps or harvest logs (Figure 12).
However, Paul Zinke36
reminds us that there may be discontinuous rings in trunks. From the
work of Fritz and Averall, 1924,38
decades are accurate enough for annual ring counts for
tells us why a growth ring may not appear:
In very old trees, ... the number of growth rings can be
misleading. In some instances an annual ring may not have
reached the level of the stump, because the rings begin at the
tree’s crown. In other instances, the pattern of growth rings
may be distorted owing to a fire scar or buttress on one side
of the trunk.
The implication in Hewes’ report is that the annual growth initiates at the crown of the
tree. However, as can be plainly seen each spring, the onset of new needle growth of redwood
starts with bright light-green soft needles, not only at the crown but simultaneously at the tips
of each branch along the entire trunk.
This growth pattern is explained by plant physiologist Katherine Esau39
in her text
The primary growth, initiated in the apical meristems, expands
the plant body, increases its surface and its area of contact
with air and soil, and eventually produces the reproductive
One reason why a tree would stop growing during this new growth time would be the
physiological stress of fire damage. Many naturalists like to compare the Coast redwood with
the Giant Sequoia. Redwood conelets produce seeds in one year, but Verna Johnston11
reminds us that Giant Sequoia cones can mature in two years, and that the cones can remain
green and attached to the Giant Sequoia tree for as many as 20 years. Age of the Giant
Sequoia tree female cones is determined by counting annual growth rings on the cone.11
Official Size Classification of Redwoods Based on dbh Diameter
Lawrence Fox III27
lists the size range classifications for redwoods: 1-6 inches are
saplings, 7-11 inches dbh are small trees, 12-24 inches dbh are medium trees, and greater than
24 inches dbh are large trees. It is assumed that seedlings and sprouts are under one inch in
Nursery Logs, Nurse Trees, and Nurse Plants
Of all the life history descriptions of the redwood, the most confusing and uncertain
terminology concerns “nursery logs”, “nurse trees”, nurse plants”, and reiterations.
Descriptive words of these behaviors are not uniform among researchers. In this Guide, I use
the following brief definitions followed by more complete descriptions below:
A Treefall is a downed tree. It can be either dead or alive. For the tree to be alive
requires that a portion of its roots must remain in the ground and be viable.
A Nursery Log is a dead treefall which has deteriorated sufficiently to expose the inner
bark and xylem wood layers, and has seedlings of any species on it.
A Nurse Tree or Nurse Plant is living, and can be standing or be a living treefall on the
ground with viable roots that gives support or protection to another plant.
A Snag is a dead standing tree or a part of a dead standing trunk (Figure 4.13).
A deteriorating log can become a nursery log. Nursery is used here instead of nurse
because a nursery is where plants are grown from seeds, cuttings, and clones. As the nursery
log deteriorates, plants and many organisms continue to thrive and compete for nutrients and
space for possibly hundreds of years. During this time, ecosystems are evolving in and on the
log, supplying energy and contributing to the biological complexity of the redwood forest.
Fallen trees form an important structural part of the stand due
to the great size and longevity of the logs. Through gap
dynamics, the redwood forest continuously renews itself while
maintaining massive tree size, high density, and structural and
report that seedlings of many plants, including redwood, can sprout
on deteriorating downed logs. However, Sugihara25
agrees with other researchers that
redwoods, unlike western hemlock, Tsuga heterophylla, and Sitka spruce, Picea stichensis,
have little success of a seedling reaching tree size if it is growing on a nursery log, because the
roots will not establish in rotten wood - mineral soil is necessary:
Fallen trees do not act directly as ‘nurse logs’, and no canopy
trees appeared to have originated on logs. Redwood seedlings do
germinate and grow on logs, and it is likely that individuals
growing on logs that were buried by sediment deposits would be
in good position to develop a root system at the new soil
Floods in the thick alluvial forests along the northern California rivers add new layers
of soil about every 30-40 years.
The redwoods then grow a new layer of roots in the new soil.5,11,36
describes other plant growths and competition on a nursery log:
The Spruce-Hemlock Nature Trail at Patrick’s Point State Park,
leads to some of the much touted ‘Octopus Trees’ that form a
regular part of the North Coastal Forests. When a tree falls in
a spruce-hemlock forest, its prostrate trunk offers a sudden
new available surface upon which plants can grow - a bonanza to
whatever can get there first. The competition in this moist
environment is fierce, with mosses, liverworts, ferns, wild
flowers, shrubs, and spruce and hemlock seedlings all in the
Note that Evarts and Popper24
and Verna Johnston11
do not use “nurse” or “nursery”
reference in their descriptions above. Sugihara25
mentioned “nurse log” for downed
deteriorating trees, but I have not read this elsewhere except in L. Eifert’s booklet THE
DISTINCTIVE QUALITIES OF REDWOODS.56
An Octopus Tree is a Sitka spruce which extends its roots down through the weak
areas of the rotting nursery log, reaching the ground on swollen strong roots. When the
nursery log disappears, the spruce is left standing on its “octopus” shaped roots. A large
amount of Sitka spruce reproduction is on dead nursery logs. Seedlings on redwood nursery
logs rarely become standing trees with roots.
In the MRA, a decomposing Douglas-fir nursery log (4.5 feet in diameter) is near
Cluster # 21 (Figures 2 and 4.16). On the dorsal surface are three redwoods (54, 32, and 30
inches in height), nine large and 12 small coffeeberry bushes, and, in damp weather in winter,
a profusion of the fern Polypodium on the sides.
I have not encountered in the literature a downed deteriorating redwood called a nurse
tree except for the 1971 following statement by Bakker: 1 (page 110)
So-called nurse trees are downed logs which are fertile
substitutes for seedlings growing like well-behaved school
children in line on the upper surface of a decaying trunk.
Nurse Tree and Nurse Plant
The foregoing discussion on nursery logs does not mean to suggest that nurse tree or
nurse plant are not a valid descriptive phrases.
in his glossary describes a nurse tree as a tree “That provides support, shade, or
other benefits to another plant.”
Examples of Reed Noss’s general title of nurse trees and nurse plants appear in
Germination of Joshua Tree seeds occurs in association with
abundant winter precipitation, but young Joshua Trees are
usually gnawed off by rodents. It seems that the only Joshua
Trees that escape predation are those that germinate under
protective cover of shrubs known as nurse plants, which include
a variety of species. After three to four years the Joshua Tree
emerges from the canopy of its host and eventually replaces it.
... As in Joshua Trees, the rare seedlings of Desert Agave
require a nurse plant. In this case, the seeds that germinate
are usually under the desert bunch-grass known as Galleta
Grass, Hilaria rigida. It has been determined that Galleta
Grass provides necessary shade and increased soil nitrogen for
the Desert Agave seedlings.12(pages 461-462)
Considering the large number of growth forms of sprouting redwoods and their
interaction with other species, “nurse” tree is too inclusive. In the Mangels Ranch Area,
California bay, arroyo willow, and oaks including the Shreve oak often are competing for
light and nutrients and affecting each other when abutting the redwood clusters. There are
several unique redwood growth patterns including the Piggyback Tree (Figures 4.3 and 6).
Role of Fog Drip
, noted that fog drip from redwood foliage could be as much as two
inches or more a day. In his study in northern California, fog is heaviest from 0700 to 1000
hours, and is at a minimum in mid-afternoon at 1500 hours. Fog concentration follows the
same hourly pattern in MRA, but fog drip is not as abundant in the MRA. It can be
determined from the stable hydrogen isotope methodology whether the water in the plant was
from rain, ground water, or fog drip. The total annual moisture input from fog drip was
between 22-58 % in Humboldt County, 26-44% in Mendocino County, and 12-18% in
southern areas. Fog drip is uncommon in the Happy Valley redwoods and may be negligible
for cluster use.
Lack of fog drip may be a major limiting factor for redwoods in Happy Valley. Dawson41
It is also possible that both redwood seedlings and understory
plant species which require forest conditions to regenerate
including fog drip and cool temperatures could disappear if the
integrity of the redwood forest is disrupted.
Fog moisture can be directly absorbed through redwood needles, but it is apparently
of lesser importance. Looking at all effects of fog, Dawson concludes from
several studies that:41
Hydrological studies have shown that moisture input to the
redwood forests from fog can constitute between 30-75% of the
annual water budget, and claims were made that fog may serve as
a potential source of water for plants.
Role of Litter, Duff, and Humus
The accumulation of leaves and forest debris on the forest floor develops into three
distinct zones. The top layer of new leaves without deterioration is litter. The next layer
where decomposition is taking place but the leaves can be identified as to species is duff, and
when the bottom material is decayed to the point that the original species source is not
recognizable, it becomes humus (Figure 4.12).
In redwood literature, the entire deposition of fresh and decomposing vegetative
material is often called “litter”, except when a particular layer is being discussed. “Litter”
over several feet thick has been noted, but in the Aptos area it is rarely more than 6 inches
thick. There are up to 20 fungal pathogens in the duff which attack the roots and kill
seedlings. This is called damping-off.
Redwood seedlings can establish in duff, on logs, in debris, and in low light intensity
as long as adequate water and light are available. It is necessary for seedlings to sprout and
survive on mineral soil. This occurs primarily after a low intensity fire, on a landslide or
slump jumble scar, on flood alluvium, or on soil exposed in a treefall gap either in the root-
pull pit or on the rootwad.25,37
Evarts and Popper24
... coarse, woody litter does not retain moisture as
efficiently as the underlying soil, and seedling roots can
quickly dry out if they are not well established in mineral
earth ... for redwoods ... lack root hairs.
If the seedlings live through these conditions, they may be consumed by banana slugs,
brush rabbits, parasitic nematodes, gray millipedes, deer, woodrats, and mice.
Too little or too much sunlight are problems for redwood growth. The redwood is
shade tolerant, and the seedlings can subsist in medium light levels under a canopy layer of
But, under full dense canopies of old-growth, especially inside slump jumble
clusters (see pages 69-71), seedlings may not survive. Evarts and Popper show how too much
bright sun can be lethal for redwoods:
In a full-sun location, a redwood will develop slowly because
it must contend with moisture loss from high rates of
In spite of all this extremely poor seed production, the redwood has thrived throughout
most of its range under natural conditions. The mature uncut forests are stable, because once a
large redwood stand becomes established, it has a long life as reported by Viers:21
Because of their longevity, only 2.5 trees per acre must reach
canopy status each century in order to maintain the less
severely disturbed stand on mesic sites in the northern part of
their range. (emphasis mine)
Role of Fire
Fire is beneficial to redwoods because seedling reproduction can be enhanced by low
intensity fires. Evarts and Popper24
describe the process:
A low intensity fire, prior to seed fall is especially
beneficial: it removes forest floor duff and kills soil
pathogens, but does not leave the hard soil surface that
typically forms after a hot sustained fire.24
Fire Scars Creating Changes in Growth Rings
If a fire is strong enough or there is repeated erosion of the bark from low intensity
fires, the cork cambium layer can be damaged leaving a fire scar that will be evident in a
disruption of the growth ring pattern.
Repeated burning can initiate heartrot, and with each additional fire, the burning of the
accumulated dead wood may create larger fire cavities. Sometimes these fire scars may extend
up through the middle of a tree for over a hundred feet forming a chimney tree (Figure 4.10).
After a fire has removed or diminished the canopy, the increased light available to the
remaining redwoods may increase growth, resulting in widening of the annual growth rings
(Figure 12). This annual increase in xylem growth may last for many years until there is
returning competition for light from adjacent trees. The annual rings will then narrow with
Mean Fire Interval (MFI)
Fire is a common subject for discussions of the redwood among naturalists and
students. The debate whether to suppress fires is a major problem in our spreading population,
because many people move into fire prone areas of the state, and then want the vegetation
removed. Or, if the scrub had been thinned from past fires and has grown to be dangerously
thick, the need for removal or thinning may become necessary. But, ecologists are concerned
about the health of ecosystems under repeated controlled burns in a vegetative community
which had achieved climax status in an area of few fires.
If the Mean Fire Interval (MFI) is lowered in an area, it would mean the fires
became more frequent, i.e., a 500 year average interval is a high MFI average frequency, and
a 20 year mean interval of occurrence would be a low MFI frequency.
To clarify, a lower MFI means fires are closer together and more numerous - 20 years is a
lower number, but with five times as many fires than when the fires are 100 years apart with a
These data are from a valuable publication available to forest managers and ecologists
written by Jason Greenlee and Jean Langenheim in 1990.42 Greenlee received his Doctorate
on this subject working primarily in Big Basin State Park. The following is a
combination of paraphrasing and quoting the essential criteria and findings for this Guide. As
throughout this Guide, the quotes are indented and in a different font than the paraphrasing.
One of the biggest problems confronting plant ecologists has been to separate the
effects of climatic and edaphic influences on vegetative patterns. Now, especially in
California‘s coastal ranges, Greenlee and Langenheim supply empirical data about the
frequency and effects of fire. I am presenting their contribution by describing the five Fire
Regimes: Lightning-volcanic, Aboriginal, Spanish-Mexican, Anglo, and Recent. The MFI in
these Regimes trends from a high MFI in the Lightning-Volcanic Regime to the lower MFI
and more fires in the more recent regimes.