Life History and Ecological Guide to the Coast Redwood


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Life History and Ecological Guide to the Coast Redwood

  1. 1. Life History and Ecological Guide to the Coast Redwood, Sequoia sempervirens for Natural History Instructors, Interpretive Specialists, and Docents Including The Plant Communities, Biota, and Topography of the Mangels Ranch Area of the Forest of Nisene Marks State Park Daniel J. Miller August, 2005
  2. 2. ENDORSEMENTS Heather Butler, Director of the Web of Life Field (WOLF) School, a K-8th grade environmental education outdoor school: “Dan Miller’s Redwood Guide is highly recommended for aspiring naturalists, teachers, and docents working in redwood regions. From basic terminology to updated figures (Which IS the tallest redwood?), the information in this Guide provides an excellent background in the natural history of the redwood even for instructors lacking a formal science background.” John Evarts, Publisher, Cachuma Press: “Dan Miller’s Life History and Ecological Guide to the Coast Redwood (Sequoia sempervirens), contains a wealth of information about the world’s tallest tree. Mr. Miller has created this guide as an aid to teachers, docents, and others who are entrusted with the all- important task of awakening appreciation for the redwood trees and ecosystems. Illustrated with clear and informative drawings, this Guide is a valuable educational resource. Reed Noss, David-Shine Professor of Conservation Biology, University of Central Florida: “Daniel Miller has produced an informative and enchanting guide to the life history and ecology of the coast redwood, the world’s tallest tree. The rich natural historical information contained in this book will be of interest to teachers, students of all ages, conservationists, and anyone else who stands in awe of these remarkable trees.” Thom Sutfin, Forest Manager of the Soquel Demonstration State Forest, California Department of Forestry and Fire Protection: “Dan Miller’s Guide is an amazing compilation of information on Coast Redwood. Nature lovers will find it fascinating.” Randy Widera, Executive Director, Friends of Santa Cruz State Parks: “In my 18 years of interpreting the Redwoods of the Santa Cruz Mountains I have never run across a guide to the Redwoods as comprehensive and regionally significant as Mr. Miller’s Life History and Ecological Guide to the Coast Redwood. This is not a guide to read through once and glean a few facts, it is a conversation with the reader and a challenge to look past myths of this grand tree to the even more amazing understandings that are being uncovered to this day. By focusing his skills as a scientist on a place that has literally been his back yard for over 40 years he brings to us in this guide a wonderful blend of individual passion and insightful first hand observations.” Copyright, © 2005 by Daniel J. Miller No part of this Guide can be reproduced without permission from the author. Copies can be made for and by natural history instructors, interpreters, docents, and students, but not sold for profit. Drawings are by the author. Contact: Dan Miller, 735 Cathedral Dr. Aptos CA 95003. The Guide was being formatted and edited for pdf down-loading by Heather Butler, Patricia Smith, Scott Miller, and Randy Widera:
  3. 3. CONTENTS Listing of Figures and Tables (iv) Acknowledgements (v) 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 Micorrhizae 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 (ii)
  4. 4. CONTENTS (continued) 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 Reiteration 54 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 Landslides 69 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 (iii)
  5. 5. CONTENTS (continued) 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 Glossary 99 Literature Cited 102 Book Reviews of Redwood Literature for Interpreters and Docents 106 Index 117 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 . 13 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 . 42 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 cluster. 74 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 (iv)
  6. 6. ACKNOWLEDGEMENTS 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 trails. 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 the text. 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. (v)
  7. 7. 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 tallest. 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. (vi)
  8. 8. 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 around me. 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 (vii)
  9. 9. 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. (viii)
  10. 10. 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 San Francisco. 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 importance. 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. (ix)
  11. 11. 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. (x)
  12. 12. 1 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.
  13. 13. 2 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 advantage? 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 other values: 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 activities. W. J. Libby3 also asked “Is sustaining biodiversity a human goal?”
  14. 14. 3 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 stated: 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 harvested. 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
  15. 15. 4 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 “ecoscape” 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
  16. 16. 5 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.
  17. 17. 6 Figure 2. Topography and vegetative classification of the Mangels Ranch Area in the Forest of Nisene Marks State Park.
  18. 18. 7 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) Plant Communities 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. Johnston11 , 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 Major10 , 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.
  19. 19. 8 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 The Climax 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 is 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.
  20. 20. 9 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 Aptos Creek. 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.
  21. 21. 10 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 plant communities. . 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 2). 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 moist micro-environment.14,15
  22. 22. 11 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 sun. 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).
  23. 23. 12 Soil Types 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 Both 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 Floods,5,14,18 landslides5 (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.
  24. 24. 13 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
  25. 25. 14 SECTION II 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 1999. Natural 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 Sequoia. 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
  26. 26. 15 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 The 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 Reed Noss5 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 feet20 dbh.
  27. 27. 16 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 years (Schoenherr12 ). 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), Viers21 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.
  28. 28. 17 Figure 4.1 Seeds and needles of the redwood, Sequoia sempervirens
  29. 29. 18 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 this tree.
  30. 30. 19 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.
  31. 31. 20 CAMBIUM 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 cambium layers. CORK CAMBIUM 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. VASCULAR CAMBIUM 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 winter. 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 chimney trees. 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.)
  32. 32. 21
  33. 33. 22
  34. 34. 23 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). Figure 4.16. 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.
  35. 35. 24 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.
  36. 36. 25 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 latitude. 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 Coast Redwood. 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 Grove. 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.
  37. 37. 26 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 biological complexity.25 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.
  38. 38. 27 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) suggests: 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.
  39. 39. 28 The USDA Northwest Forest Plan perpetuates the confusion. Tuchman et. al.28 suggested that: ... 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 older. 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).
  40. 40. 29 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 Evergreen29 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 Forests30,31,32,33 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).
  41. 41. 30 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 uneven-aged forest. 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 tree farm.34 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- growth. 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.
  42. 42. 31 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 relates: 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 Seed Germination Viers21 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.
  43. 43. 32 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). Becking37 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 , muses: 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.
  44. 44. 33 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 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 redwoods. Hewes20 tells us why a growth ring may not appear:
  45. 45. 34 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 PLANT ANATOMY: 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 organs. 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 diameter. 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:
  46. 46. 35 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). Nursery Log 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. Sugihara25 states: 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 biological complexity. Noss5 and others40 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 surface.25 Floods in the thick alluvial forests along the northern California rivers add new layers of soil about every 30-40 years.
  47. 47. 36 The redwoods then grow a new layer of roots in the new soil.5,11,36 Verna Johnston11 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 running. 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.
  48. 48. 37 Noss5 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 Schoenherr:12(page 454) 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 Todd Dawson41 , 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.
  49. 49. 38 Lack of fog drip may be a major limiting factor for redwoods in Happy Valley. Dawson41 summarizes: 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
  50. 50. 39 Evarts and Popper24 report: ... 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 60-80 percent.24 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 transpiration.24 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.
  51. 51. 40 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 increased shading. 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 high MFI. 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 at UCSC43 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.