University of the Pacific Scholarly Commons University of the Pacific Theses and Dissertations Graduate School 1964 Ecology of the Sclerophyllous plants of Mount Tamalpais George Edwin Corson Jr. University of the Pacific Follow this and additional works at: https://scholarlycommons.pacific.edu/uop_etds Part of the Life Sciences Commons Recommended Citation Corson, George Edwin Jr.. (1964). Ecology of the Sclerophyllous plants of Mount Tamalpais. University of the Pacific, Thesis. https://scholarlycommons.pacific.edu/uop_etds/1558 This Thesis is brought to you for free and open access by the Graduate School at Scholarly Commons. It has been accepted for inclusion in University of the Pacific Theses and Dissertations by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. ECOLOGY OF THE SCLEROP HYLLOUS PLANTS OF MO UNT TAMA LPAIS A Thesis Pr esented to t he Faculty of the Department of Biological Sciences University of t he Pacific In Partial Fulfillment of the Requirements for the Degr ee Master of Arts by Ge orge Edwin Corson Jr. August 1964 This thesis, written and submitted by is approved for recommendation to the Graduate Council. Department Chairman or Dean: Thesis Committee: _..:..d-=~~:....._-~_..:._ __~.c__-----' Chairman TABLE OF CONTENTS PAGE I NTRODUCTION . 1 GEOLOGY • • • • • . • • • • • • • . 6 TOPOGRAPHY AND BOUNDARI ES . • • . • • . 8 CLI.lJIA TE • • • • • • • • • • • • . 9 HISTORY • . • • • • • 0 . 0 • • 17 ECOLOGY . • • • . 22 Introduc·t ion . 22 Methods and Procedure • . 24 ~e~uoi a semEervirens Association • • . • • • • • 30 Lithocar2u~-Umbe llulari ~-Arbutus Association • • 36 Litho c ~rp~s aspect • • • . .. 40 Pseudotsuga aspect . • • • • • • • 0 • • 0 • • • • 42 Umbellulari a ~ Association . 45 Chaparr a l Association • • . • • • • • • . 49 Arctosta2pylos gushingiana aspect • 51 Adenostoma fascicul¥tum aspect • • • • . • . 54 Castanopsis chrysophylla aspect . • • • . .. 57 Arctost aphyl os canescens aspect • . • • . • • • 59 Arctostaphylos montana aspect • • • . • • • • • 59 Cupressus sargcntii Association • • • • • • • • . • • 59 SUMMARY •. 69 LITERATURE CITED . 71 LIST OF TABLES '!'ABLE PAGE I. Precipitation: Honthly and Seasonal, Averages in Inches • • • . • • • • • • . 10 :.II. Average Number of Days with 0.01 Inch or l•lore of Precipitation . 11 III. Greatest Precipit ation in T\tenty-four. Hm.,rs on Mt. Tama1pai s - T"t'lenty-t\'ro Year Record • • 11 IV. Average 1-iaximum , Average Minimum, and Average Temperatures . • . • • • 12 v. Average Hourly \find Velocity (niles) on Mt. Tama1pais - Twenty-two Year Record • . 13 VI. Maximum Wind Velocity, Direction, and Date on Mt. Tamal pais - Twenty-two Year Record . 13 VII. Frost Data: Aver age Dat es and Length of Season • • • • • • • • • • • • • • • • • • 14 VIII. Size Class Distribution of Tree Species and Number and Presence of Subordinate Species in Two Stands of Sequoi a Sempervirens Association . I X. ~~ocarEYJL-Umbel1ulari a-Arbutus Association • • X. Coverage Data for the Lithocarpus-Umbe1lulari~- Arbutus Association; Lithocarpus Aspect . 41 v TABLE PAGE XI. Size Class Distribution of Tree Species in Llthocarpus-Umbellularia-!!butus Association; Pseudotsuza Aspect • . 43 XII. Coverage Data for the Umbellularia Cal i forni~ Association • • . ~ . 47 XIII. Coverage and Frequency Data for the Arctostaphylos Cushingiana Aspect of the Chaparral Association • • • • * • • • 52 XI V. Cover~ge and Frequency Data for the Adenostoma Fasciculatum Aspect of the Chaparral Association • . • • . • . • . 55 XV . Coverage Data for the ~~stanopsis Chrysophylla Aspect of the Chaparral Association • • • • . • • . XVI. Coverage and Frequency Data f or the Arctostaphxlos Canescens Aspect of the Chaparral Association • . 60 XVII. Coverage and Frequency Data for t he Ar cto stap~yl~ Montana Aspect of the Chaparral Association • • • . • • . 62 XVIII. Coverage and Frequency Data for the CuEressus Sargentii Association • • • • • • . 64 vi TABLE PAGE XI X. Distribution and Rol e of Tree Speci e s of the Tamal pais Study Ar ea . • • • • . 66 XX . Distribution of Non-Arborescent Species . 67 LIST OF' FIGURES FIGURE PAGE 1. Stand Representative of the Sequoia sempervirens Association • • • • • • • • • • • • 33 2. General Vie\'.r of Seguoia sempervirens Association in a Moist Ravine • • • . • • • • • • • • • • • 33 3. Re l ationship of lLeguoi~ Association to a Water Source • • • • • • • • • • 0 • . 35 4. Stand Representative of the Lithocarpus- Umbe llular~-Arbutus Association • • • . 39 5. Stand Representative of the Lithocarpus Aspect of the Lithocarpus-Umbellularia­ Arbutus As sociation • • • • • • • • • • . 41 6. Stand Representative of Pseudotsuga Aspect of the Lithocarpus-Umbellularia-Arbutus Asso ciation • • • • • • • • • • • . 44 7. Stand Representative of Umbe llularia Association • • . • • • • • • • . 8. ]~p~Jlylari ~ As sociation as it Ascends and Merges with the Chaparral . 9. General View of the Arctosta~hylos cushin~iana Aspect of the Chaparral Association on the South Slope of Mt. Tamal pais ••••••• . 53 10. General Aspe c-t• of the Adenostorna Aspect of the Chaparral Association • • . • • • • • • • • 56 viii FIGURE PAGE 11. Representative Stand of Arctostaphylos canescens Aspect of the Chaparral Association . 61 12. Representative Stand of 9upressus sargentii Association • • • • • • • 0 • • • • • • • • • • 65 LIST OF PLATES PLATE PAGE l. 11ap Shol'ring Location of the Study Area • • • . 3 2-6. Overlay 14ap of the Various Associations • • • • • 27 7. Map Sho\!nng Location of Sampl e Stands • • • • . 29 ECOLOGY OF THE SCLEROPHYLLOUS PLANTS OF MT. TAMALPAIS I NTRODUCTION Mt. Tamal pais, 2571 feet in elevation, is found eighteen miles north of San Fr ancisco in southern Mari n County (see Pl ate 1) . My interest i n the mountain began during my childhood. Mt. Tamal pai s was chosen as the area for this ecological study because of my personal interest as well as my belief t hat this is an excell ent area which demonstrates a gr eat diversity of pl ant communities in a small area. Despite its close proximity t o a worl d por t and me tropolis , its slopes still displ ay a wildness and natural beauty that have been but little impaired. The flora of the mountain has remained relatively unaltered as compared with other areas of t he Bay Region and demonstrates ready accessi bility to detailed e cological study. The study began duri ng the spring of 1963 when plant specimens were first collected. Af t er a period of recon­ naissance and mapping of the vegetation, quantitative samples were taken in t he study area in hopes that relationship s could be established between pl ant communities and environmental f a ctors. 2 Pl at e 1 Map showing l ocation of the study area. 3 ' MT. TAv:MALPA[£} PACIFlC OCEAN SAN MT, TAMALPAIS STUDY AREA long 122 o 34 ' 30" lot. 3r 55' 71" 4 The veget ation of Mt. Tamal pai s presents probl ems that 't•rould require many years of serious study. This inves­ tigation endeavors to define the several plant associ ations, to relate t he associati ons t o t he environment, and to present some of the many probl ems that can be answered only by continued ecologi cal study. Past \'Tork i n the area has been mainl y of a t axonomic nature. Dr . Herbert L. Mason , Director of the University of Californi a Herbarium , has stated (personal communication), "I may say I do not know of any ecological studies that have been made on Mt. Truna l pai s. There certainl y are many prob­ lems t o t a ckle i n the area . " Botanists have collected on Mt . Tamal pais and in Marin County since 1800. The area supplied the early botanists of the Cal ifornia Academy of Sciences with a profitable field for exploration and collec­ tion. Some of t hese earl y workers were Albert Ke llogg, H. Behr , II . Bol ander , Katharine and T. S. Brandegee , Alice Eastwood , and E. L. Gr eene. In 1885, E. L. Greene became instructor of Botany at t he Universit y of Califor ni a where he imparted his interest in Marin flora t o V. K. Chessnut , E. Drew , c. A. Michener, F. T. Bioletti, and U. L. Jepson. John Thomas Howe ll's book , r~ar i n Flora, has been an invaluabl e aid in this project . Hi s \·mrk on the mount ai n was largel y of a descriptive nature and no quantitative data have been published. He stated {personal communi cation), 5 " I don't knm.t of any ecological study on Mt. Tamalpais since I did my field \'fork for Marin Flora before December, 1949 . It is a marvelous field for study and I hope you have abundant success in your work." GEOLOGY During the Jurassic and early Cretaceous periods the Coast Ranges of California wer e covered by a shallow sea. From 20 , 000 to 30,000 feet of l ate Jurassic sediments were depo sited i n the geosyncline wher e the present Coast Range was born. As the ar ea was upl ifted and then subsided several times throughout the Eocene, Pliocene, and Pleistocene, the sea invaded the low areas of the range and flooded the inland va lleys of Cal ifornia . There were regions, including Mt. Tamalpais, that r emained above the sea. The i nundated areas were covered by new deposits of sediment while the high regions remai ned untouched, other than for erosion , and ar e now found with the ol d Franciscan deposits of the Jurassic and early Cretaceous periods. These deposits are made up of har d gray sandstone, dark sha le, and serpentine, all of wh ich are pr esent on Mt . Tamal pais (Taliaferro, 1951). The Franciscan formation is widespread in the Coast Ranges but almost everywhere except Mt . Tamalpais it is found together with younger sedimentary rocks. Mt. Tamal pais and t he surrounding area, ther efore, has been above sea l eve l as long as any area in coastal California and much longer than most ar eas (Howell, 1949). The rugged country of Mt . Tamal pais i s especia lly rocky and on the steep slopes t he soil l ayer is extreme l y 7 thin or entirely l acking. Outcr·ops of serpentine, sandstone, or shale are quite frequent in t he area.