THE OCCURRENCE AND DISTRIBUTION OF UMBELLULARIA CALIFORNICA

IN THE BIG BASIN AREA, SANTA CRUZ MOUNTAINS, CA

A Thesis Presented to the Faculty

of

California State University, Hayward

In Partial Fulfillment

of the Requirements for the Degree

Master of Arts in Geography

By

Steven D. Guiney

October 1990 THE OCCURRENCE AND DISTRIBUTION OF UMBELLULARIA CALIFORNICA

IN THE BIG BASIN AREA, SANTA CRUZ MOUNTAINS, CA

By

Steven D. Guiney

Approved: Date: s ~ /?f't1 ~7f~~/W /2 /Vt1Y6H~~ /9?a

ii TABLE OF CONTENTS

Chapter Page

I. INTRODUCTION ·· · · · ·· · · 1 II. AN OVERVIEW ·· · · · ·· · ·· · ·· · · 6 III. BIG BASIN PHYTO-PHYSICAL GEOGRAPHY ···· 9 IV. HISTORICAL PLANT GEOGRAPHY · · 44 V. ECOLOGICAL PLANT GEOGRAPHY · · · · 47 VI. PHYSIOGRAPHIC PLANT GEOGRAPHY · · · · · · 52 VII. DISTURBANCE FACTORS · · · 54 VIII. CONCLUSIONS · · · · · ··· · · · · · 58 BIBLIOGRAPHY · · · ·· · ·· · ·· 61

iii '""-<-- LIST OF FIGURES AND TABLES

Figure Page

1 Study Area .. · ·· · ··· . . 4 2 Elevations ...... · ···· · 11 3 Climatograph Explanation · · · · · · 17 4 Santa Cruz Climatograph · · · 18 5 Henry Cowell Climatograph ·· · 19 6 Ben Lomond Climatograph ·· ·· · · 20 7 Big Basin Climatograph · · ·· · 21 8 Henry Cowell Transects · 24 9 Portola Transects · ·· 25 10 Big Basin Soils ···· . . 26 11 Big Basin Vegetation · · ·· 28

Table

1 Individuals/Species. 34

2 Density 35

3 Coverage . 36

iv LIST OF PHOTOS

Photo Page

SITE 1 37

SITE 2 38

SITE 3 41

SITE 4 42

SITE 5 43

v INTRODUCTION

The coastal redwood forest of Central California is composed principally of four kinds of trees: coast redwood

(Sequoia sempervirens), Douglas fir (Pseudotsuga menziesii), tan oak (Lithocarpus densiflora) and California bay

(Umbellularia californica). All of these are found in Big

Basin Redwoods State Park and adjacent areas in the Santa

Cruz Mountains.

Big Basin, unlike most other areas of the Santa Cruz

Mountains, has relatively few bay trees. In fact there are only ten areas where Umbellularia is found in the 16,000 plus acres of Big Basin Redwoods State Park. That the

California bay has been conspicuous by its scarcity has been noted by several authors (Orr, 1936; Meadows, 1950; Cooney­

Lazaneo and Lyons, 1981), but there has been no attempt to document the location of all occurrences of Umbellularia in

Big Basin nor any attempt to account for the relative absence of this tree. Purpose

The purpose of this thesis is to document the location of Umbellularia in Big Basin Redwoods State Park, compare these locational occurrences with other areas outside Big Basin and attempt to determine why the

California bay is so rare in Big Basin.

1 2

Methodology

Several research methods were used in this investigation. Field verification was made of all the known locations of occurrence of Umbellularia in Big Basin, as listed in the Natural History Survey File at Big Basin

Redwoods State Park headquarters. Likely locations of occurrence, based on preferred habitats of Umbellularia

(Folwells 1953, Peattie 1953 and Stein 1965), were also field checked in Big Basin, Henry Cowell Redwoods State Park and Portola State Park. These latter two parks were investigated for comparative data. The focus was on Big

Basin; no other area was checked for likely locations of occurrence as intensively as Big Basin. Surrounding flora and site conditions (slopes, indications of ground disturbance, etc.) were noted at known and found locations of occurrence, and transects were run at nine sites.

The literature concerning historical or evolutionary plant geography with special reference to Umbellularia and ecological plant geography with special attention to reproductive ecology of bay was reviewed as an aid in determining likely unknown locations of occurrence, and in understanding under what conditions Umbellularia reproduces.

Coincidences between occurrence of bay and old­ growth, virgin redwood forest; areas of disturbance (e.g. logging, fire, landslides); landforms; and soils were also 3

investigated.

Study Area Description

The study area includes Big Basin Redwoods State

Park and adjacent areas in the Santa Cruz Mountains. The most intense scrutiny was given to Big Basin, the majority of which is the Waddell Creek watershed. Big Basin is located in the Santa Cruz Mountains of northwestern Santa

Cruz County, California. It ranges in elevation from sea level to over 650 meters above sea level, from the marshy mouth of Waddell creek through dense redwood forest to chaparral-covered ridgetops. The other areas which are included in this study are smaller than Big Basin and do not have the variety of vegetation types nor as great relief.

The study area lies between 37 0 07' North latitude and 37 0

12' North latitude and 122 0 10' West longitude and 122 0 20'

West longitude (Fig. 1).

The entire area consists of steeply sloping hills, mountains and canyons with few large, level areas. The main exceptions to this are the center of Big Basin, the visitor center area of Henry Cowell Redwoods State Park and along lower Waddell Creek. Even these areas are not unbroken expanses of level terrain.

With the exception of the trail from the coast at

Rancho del Oso, all routes into Big Basin lead down once the park boundary is reached. Big Basin is truly a descriptive 4

~ (:) 'P 1.- \ /~ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ Figure 1: Study Area ~ 5

name. If you walk around its rim, which is breached only where Waddell Creek passes in a deep canyon to the coast,

Big Basin appears to be rather a lumpy basin for it has

hills and ridges within it. Covered variously with

chaparral, the more xeric species of mixed evergreen forest

and knobcone pine (Pinus attenuata), the rim is a harsh

environment. Although very wet in winter, the rim

experiences hot, dry summers with little or no fog.

Descending from the rim, one passes from this harsher

environment into the wetter, cooler environment of the mesic

mixed evergreen forest and in the heart of Big Basin, the

redwood forest. The former is dominated by Douglas fir; the

latter by coast redwood with associates such as Douglas fir

and tan oak. On the Basin floor is virgin redwood forest.

It shows no signs of the logger's axe, crosscut saw or

chainsaw. The redwoods here are massive and spaced far

apart. Interspersed among them are Douglas fir and tan oak.

The understory is mostly huckleberry (Vaccinium ovatum) .

There is no pungent odor of wet or crushed bay leaves;

virtually nowhere does one see the shiny green leaves of the

California bay tree. In fact, a very sharp lookout and some

amount of luck are necessary to see any bay at all in Big

Basin. AN OVERVIEW

Umbellularia californica (H. & A.) Nutt. is monotypic; it is the only species in its genus. A member of the Lauraceae, or laurel family, California bay is presumably related to the sassafras (Sassafras albidum) of the Southeastern United States; the Laurus nobilis, or poet's laurel of Mediterranean Europe; and various trees of the genus Cinnamomum, including the camphor tree (Cinnamomum camphora), of East and Southeast Asia (Folwells 1953,

Peattie 1953).

Origins and Range

As a species, bay probably developed after its genetic lineage came in contact with redwood forest members (Mason 1947). An exact area and time of origin of its genetic lineage is unknown, but leaf characteristics of fossil and living individuals are similar to leaves of present day tropical plants (Chaney, 1947). California bay is found along the Coast Ranges in a continuous distribution from the Umpqua River Valley of Oregon to the San Francisco

Bay Region. South from there to southern San Diego County it has a discontinuous distribution. The tree also occurs along the Cascade Range and the Sierra Nevada from

Mt. Shasta to northern Kern County. Generally found from sea level to about 1200 meters in elevation, bay grows somewhat higher in elevation in the extreme southern portion of its

6 7

range (Folwells, 1953; Critchfield and Griffin, 1972).

Autecological Characteristics

Umbellularia will grow on many soils if there is

constant and plentiful moisture (Folwells, 1953). The most

favorable sites for Umbellularia are in riparian zones,

along creeks and streams. Other sites with deep, well­

drained alluvial soils, such as valley bottoms which are

periodiclly flooded, are also very good habitats for the bay

tree. It will grow elsewhere but, in general, bay grows in moist soils.

Bay flowers at an early age although seed production

is not abundant until the tree is 30 to 40 years old

(Folwells, 1953). Insects are the main pollinators of the

flowers which appear from December to May. Distribution of

the large seed is mostly by gravity and water, but rodents

and birds also play an active role. Umbellularia seeds

germinate best when they are buried, but due to their large

size they require disturbance of the ground or covering by

silt deposition to achieve germination. Those seeds that do

germinate, do so in the autumn, late winter or early spring,

depending on local conditions of temperature and

precipitation. Umbellularia also reproduces vegetatively by

sprouting (Folwells, 1953; Stein, 1965).

Cultural Uses

Currently, there are no cultural uses of Umbellularia 8

within Big Basin, other than scenic ones, since there are so few trees and all plants are protected within the park.

Outside of the park, especially in the adjacent San Lorenzo

Valley, there are retail sales of various types of bay burls and other parts of the trunk and branches of the tree that have been made into small tables, bowls and similar objects.

There is a larger trade in these items along the North

Coast of California and in Southwest Oregon where the tree is commonly called Oregon Myrtle. The oil from the wood and leaves has been used as a pharmaceutical product and as an ingredient in preparations for treatment of headaches, colic and diarrhea (Peattie, 1953). Historically, in Big Basin proper there was probably very little use of the tree since the area was so remote. BIG BASIN PHYTO-PHYSICAL GEOGRAPHY

The earth, presenting varying angles seasonally to the sun, is heated differentially. The equatorial regions, having the smallest departure from the vertical with respect to the sun, are continually heated. The warm air rises and moves away from the equatorial regions toward the poles. It then cools and descends, generally around 30° North and

South latitude, creating areas or cells of high air pressure. The air is compressed by its descent and reaches the earth's surface as warm, dry, stable air.

Southwest of California, over the Eastern Pacific

Ocean, is an area of high air pressure known as the Pacific

High. This semi-permanent mass or ridge of dry, stable air migrates north and south as the earth tilts first toward the

sun in the Northern Hemisphere summer and then away from it

in the Northern Hemisphere winter.

As water flows from a higher elevation toward a

lower one, so air flows toward areas of lower pressure.

High pressure blocks air movement. In the case of summer in

the Northern Hemisphere, the Pacific High moves north as a

reaction to the heating of the earth's surface progressively

farther north. In winter, the surface of the Northern

Hemisphere cools and the Pacific High moves southward.

Thus, in summer, storms crossing the Pacific Ocean or coming

down from the Gulf of Alaska are blocked from making a

9 10

landfall on California; instead they bring rain to coastal

British Columbia, Washington and Oregon. In winter there is no ridge of high pressure off California; storms bring rain to the state at that time. This cool, wet winter and warm, dry summer is characteristic of a Mediterranean climate.

Winds in a high pressure area rotate clockwise in the Northern Hemisphere. When the Pacific High is in place

southwest of California during the summer, winds are generally from the northwest. These winds encounter friction at the ocean's surface which creates an overturning of the ocean water and an upwelling of the cooler subsurface water.

When the relatively warm moisture-laden marine air meets the cooler water the air cools and the moisture in it condenses to form fog. As the interior of California heats under the

increasingly direct rays of the sun, the heated air there

rises, creating an area of low pressure. Driven by northeast winds, cooler, heavier marine air moves landward toward the

area of low pressure. This layer of marine air is usually

about 450 m to 600 m thick. Coastal forests often become

cloaked in fog which condenses on the trees, providing moisture in an otherwise summer-long drought (Gale, 1980).

The rim of Big Basin ranges from about 400 m above

sea level on the west and southwest to about 500 m on the

east and to about 650 m on the north (Fig. 2). Fog usually

penetrates Big Basin from the south and southwest through 11

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Waddell Creek canyon. This route provides the closest access to the floor of Big Basin from the ocean (about

17 km) and the only open one. Still, it is quite constricted as it passes through the gorge of East Waddell Creek to reach the floor of Big Basin which lies about 300 m above sea level. This constriction, and the lifting of the fog as the marine air layer moves inland and topographically upward, has two effects. It causes the moisture to condense and precipitate out in the form of fog drip, and consequently the air becomes drier as it penetrates farther inland. Thus, if the marine air layer reaches the basin floor it has been dried to such an extent that it only occasionally produces fog. To the east, marine air is blocked by East Ridge which forms a divide between Waddell Creek and the San Lorenzo River drainage. Marine air moving up the

San Lorenzo Valley must come about 25 km from the ocean and rise some 500 m to enter Big Basin over East Ridge. The result is more pronounced than when the air comes up Waddell

Creek. Fog rarely enters Big Basin from the San Lorenzo

Valley. The third potential avenue for marine air to enter

Big Basin is if it comes up Pescadero Creek from the northeast. Here the task is even more difficult since the air must travel about 30 km from the ocean and rise about

650 m to reach over China Grade. Since the air mass is usually no more than 600 m thick, it very rarely enters Big 13

Basin from the north. Radiation fog may also form on the floor of Big

Basin, usually in the winter when the ground is wet from the copious rainfall and there are clear, cold nights. In these instances the relatively warm air from the floor rises and is cooled as it does so. The moisture within it condenses and forms fog. Personal observation of this phenomenon in the early morning from China Grade at about 600 m elevation places the thickness of the radiation fog at about 100 m to

150 m. Thus, we find that Big Basin's rim is rarely foggy while its floor may have occasional fog.

The average annual rainfall in Big Basin is 1414 mm

(Big Basin Redwoods State Park Weather Records). On the coast at Santa Cruz, 25 km southeast of Big Basin, the average annual precipitation is 854 mm or only 60 percent of

Big Basin's (National Climatic Data Center 1976-1986). This is due to local orographic lifting of saturated air masses.

As the onshore flow of air meets the mountains, it rises and cools, causing the water vapor within it to condense and precipitate out as rainfall. The precipitation at Big Basin has varied from as little as 550 rom in drought years to over

2350 mm in very wet years. Three-quarters of the annual precipitation falls from November through March. The summers are usually not entirely devoid of rainfall.

Subtropical disturbances commonly reach Big Basin once or 14 twice during the summer, bringing clouds and a very small amount of rain. Humidity generally ranges from 83 percent in the mornings to 45 percent in the afternoon. Average temperatures range from slightly above freezing to over 28° C.

Periods of freezing temperatures do occur in the winter and summers usually see a few days over 30° C and even, occasionally, over 38°. Fog adds a small amount of moisture and is important in reducing the amount and rate of evapotranspiration (Big Basin Redwoods State Park Weather

Records) . The storms in winter that bring rain move not only generally from west to east but also rotate counterclockwise as they move. As the storm reaches the coast of California and Santa Cruz County, winds are usually from the south or southeast. The San Lorenzo River Valley, immediately east of Big Basin, runs south-southeast to Monterey Bay at Santa

Cruz. Winter storms are funneled up the valley. Henry

Cowell Redwoods State Park at Felton, some 15 km southeast of Big Basin, has average annual precipitation of 1502 mm, slightly more than Big Basin, even though the elevation is only 75 m at Felton, while the elevation at Big Basin is 305 m

(National Climatic Data Center 1976-1986). Most likely this is due to the steep gradient and narrowness of the 4 km long San Lorenzo River gorge below Felton. The saturated air is lifted rapidly and is in a deep, steep-sided, narrow 15

canyon until it reaches Felton. This causes rapid cooling and condensation of the moisture resulting in increased precipitation. Upstream the river flows through a valley rather than a canyon and the precipitation is less. Ben

Lomond, 5 km upstream from Felton at 137 m above sea level, has an average annual precipitation of 1408 rom, virtually identical with that of Big Basin and slightly less than that of Henry Cowell (National Climatic Data Center, 1976-1986).

Precipitation and temperature data were collected and tabulated for Santa Cruz, Henry Cowell Redwoods State

Park at Felton, Ben Lomond and Big Basin. No weather data were collected for Portola State Park, just north of Big

Basin in the Pescadero Creek drainage, where transect data about vegetation and flora were collected, because the State has not kept any weather records.

Climatographs based on these data show roughly

similar curves for precipitation and temperature at these

stations, with Santa Cruz being the most different. This is due to its location on Monterey Bay and the moderating

effects of the waters of the bay. Farther inland at the three mountain stations there is a greater range of diurnal

and seasonal temperatures and there is greater precipitation

(Figs. 3, 4, 5, 6, 7).

Landforms

Big Basin is essentially a bowl with several north- 16

south trending ridges in it and with a section of its southern rim sliced out where Opal and Bloom's Creeks join to form the East Waddell Creek and flow to the Pacific. The rim and ridges of Big Basin are the result of Pleistocene uplifting, and associated erosion has produced the steep sided stream canyons (McJunkin, 1983).

The high annual precipitation coupled with the soils and rocks have resulted in a landscape that is extremely rugged with knife-edged ridges and very steep slopes. Total relief within the East and West Waddell basins is approximately 600 m (Fig. 2). During periods of Pleistocene glaciation, stream courses were steepened and many slopes were undercut, creating numerous landslides. With the rise of sea level following deglaciation, many stream gradients were lessened somewhat, causing alluvial backfilling in local stream estuaries and areas such as lower Waddell Creek which stabilized the toes of many of the larger landslides

(McJunkin, 1983). The area is still subject to landsliding and other types of mass-wasting each winter.

Level, open areas are rare. The largest such areas are in the Opal and Bloom's Creeks drainages, where most of the park facilities are located. This area is approximately

2 square km in size. It is mostly Quaternary alluvium into which the creeks have become entrenched. Above the junction

of Bloom's and Opal Creeks there are very few flood plains. 17

a OIG 3AOW 130"') 12.'· 1414 .. (101

300

200

b 40." 21.6 100

80

Fig. 3 a = station and elevation, average annual temperature and precipitation, years of weather observation b = highest recorded temperature, average daily oaxiourn for warcest month c = average daily Dininum for coldest month, lowest recorded temperature d = precipitation curve e = Donthly precipitation in excess of 100 mm f = temperature curve g =period of drought h =months that actual daily minimum Day fall below O··C / Source: D. E. Johnson, "Notes and news," Madroiio., Vol. 29 (1982). pp. 122-23. 18

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300

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The streams are so entrenched that even in periods of very heavy precipitation and runoff they rarely, if ever, rise above their banks. Personal observation of these streams from 1980 to 1987 never once revealed the streams rising over their banks. This includes early January 1982, when over 330 mm of rain fell in a 36 hour period. Elsewhere the streams fill the bottoms of steep, V-shaped canyons. There are areas which receive deposited sediment, but these are very small, usually less than 5 m square.

The portion of Henry Cowell Redwoods State Park where transects were made is partly a flood plain. Along the east bank of the San Lorenzo River is a depositional feature about one-quarter km wide and 1.5 km long, extending to 3 km long outside the park boundary (Fig. 8). The transect area in Portola State Park is in a flood plain also, but the feature there is much smaller, about 50 m wide and 100 m long, and is more of a beach or bar at a bend ln the creek (Fig. 9).

Soils

The soils of Big Basin are mostly derived from sedimentary rocks, principally sandstone and shale. There are eight soil types within the study area (Fig. 10). These soil types are groupings of one or more soils or soil complexes which differ within each grouping by steepness of slope on which the soil is found and/or percentage of 23

constituent soils. For example, within the Lompico-Felton type there are three complexes: 1) Lompico-Felton 5-30 percent slopes, 2) Lompico-Felton 30-50 percent slopes, and

3) Lompico-Felton 50-75 percent slopes. Respectively, these have a Lompico loam soil contributing 30 percent, 35

percent, and 35 percent; and a Felton sandy loam soil

contributing 25 percent, 30 percent, and 30 percent.

Various other soils make up the remainder of these Lompico­

Felton complexes. On the other hand, the Soquel loam type

consists of only two soils, differing primarily by slope.

Most of the soils in Big Basin range from moderately deep to

deep and from well drained to excessively drained. They are

generally moderately to strongly acidic (Soil Conservation

Service, 1969).

Soils in areas near Big Basin have similar

characteristics. At Henry Cowell, the picnic area adjacent

to the transect area has Elder Sandy Loam soils and supports

riparian woodland. Transect number 3 lies in a transitional

area between Lompico-Felton complex and Soquel Loam. The

other two transects made at Henry Cowell are a few meters

higher and farther away from the San Lorenzo River on Soquel

Loam (Fig. 8). At Portola the transects lie on Hugo and

Josephine loams which support mixed evergreen forest with

Douglas fir (Fig. 9). 24

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Soil Type 1) Ben Lomo~d-Catelli-Sur Complex 2) Ben Lomond-Felton Complex 3) Lompico-Felton Complex 4) Maymen-Rock Outcrop Complex 5) Santa Lucia Shaly Clay Loam 6) Soquel Loam 7) Sur-Catelli Complex 8) Xerorthents-Rock Outcrop Complex 27

Vegetation and F10ra

For the purposes of this thesis, four vegetation groups are described for Big Basin: 1) redwood forest, 2) mixed evergreen forest with Douglas Fir, 3) chaparral, and

4) riparian woodland (Fig. 11). The description of these vegetation types and their flora is not meant to be exhaustive. Only the major species, in terms of visual abundance or possible significance to this thesis, are included. Many of these vegetation types have never been logged or otherwise significantly disturbed by human activity (Langenheim, et al., 1983).

Redwood forest occurs mainly along the canyon bottoms of upper West Waddell Creek and Berry Creek, and along the East Waddell Creek tributaries Opal, Sempervirens,

Union and Bloom's Creeks. These last four are found on the floor of Big Basin. The most common species here is the coast redwood (Sequoia sempervirens). Additionally,

Douglas fir (Pseudotsuga menziesii), tan oak (Lithocarpus densifIora), and huckleberry (Vaccinium ovatum) are found.

In Big Basin, tan oak is the main associate of redwood in the redwood forest.

The mixed evergreen forest with Douglas fir occurs along the upper, drier portions of the redwood forest and above, covering most of the ridges. The main floristic 28

• =SITE NUMBER

Figure 11: Vegetation Type 1) Redwood Forest

2) Mixed Evergreen Forest

3) Chaparral 29

elements are Douglas fir, tan oak, coast live oak (Quercus agrifolia), madrone (Arbutus menziesii), and various species of Ceanothus.

Chaparral occurs in areas of poor, dry soils on steep, south and west facing slopes and some ridgetops.

Various oaks (Quercus spp.), manzanitas (Arctostaphylos spp.), and species of Ceanothus are found, as well as knobcone pine (Pinus attenuata), coyote brush (Baccharis pilularis var. consanguinea), yerba santa (Eriodictyon californicum), and chamise (Adenostoma fasciculatum).

Riparian woodland occurs only below Big Basin proper, along lower Waddell Creek This is a floodplain and has sandy soils. The main species here are Umbellularia, boxelder (Acer negundo), big leaf maple (Acer macrophyllum), alder (Alnus rhombifolia), black cottonwood (Populus trichocarpa), and sycamore (Platanus racemosa).

The foregoing descriptions apply to Henry Cowell and

Portola as well, with the exception that Portola has no well developed riparian woodland as occurs along Waddell Creek below the junction of its east and west forks and along the

San Lorenzo River in the northern park of Henry Cowell.

Distribution of ombellularia in Big Basin

The nature of the distribution of bay in Big Basin relative to other areas in the Santa Cruz mountains has been the primary object of this research. Umbellularia was found 30

~n 10 sites (Fig. 2). Five of the sites were confirmations of listings ~n the Big Basin Redwoods State Park Natural

History Survey File. There were six sites listed in that file, all of which were field checked. Five of those sites were confirmed as locations where bay grows and one site had no bay trees extant. This latter site had been observed in

1950. Although there has been no known disturbance of the area since then, none of the trees were found there. Five other sites were discovered during field reconnaissance along trails, roads and areas of likely suitable habitats.

Transects were run at sites 5 (two transects, 5 and SA, SA about 50 m east of 5), 9 and 10. Two transects were run at

Portola State Park and three at Henry Cowell Redwoods State

Park (Figs. 2, 8, 9 and Tables 1, 2, 3).

Site 1 is in a park residence area adjacent to a garden. This area has been greatly disturbed by the residential development. One individual exists at this location.

Site 2 is an elongate area 0.5 km long by 0.1 km wide ranging from 400 m to about 425 m above sea level. At the upper end of this location are two clusters (clones?) of mature bay trees with diameter at breast height (dbh) ranging up to 40 cm and height up to 13 m. Approximately

137 m west (downhill) of those clusters is a single

individual of 25 cm dbh and 8 m height. About 183 m west of 31

individual, in a 9 square meter area behind a park residence are four seedlings from 15 cm to 75 cm in height. The entire area of location 2 has been logged and the lower portions of it are used by the park as a storage area for building materials.

Site 3 is approximately 65 m downstream from

Sempervirens Reservoir, the park water supply, along

Sempervirens Creek. It consists of one small cluster of

three trunks from 10 cm to 30 cm dbh and from 7 m to 12 m tall, respectively. The cluster is growing in the bank of the creek. There is no other riparian vegetation in that

location; it is mixed evergreen.

Site 4 is along a trail near the base of Slippery

Rock and is a single cluster of 10 trunks ranging from 2.5

em to 12.5 em dbh and from 3 m to 7 m tall.

Site 5 is adjacent to a campsite in Bloom's Creek

Campground at the site of a former stable. There is one

individual 15 em dbh and 8 m tall.

Site 6 is at the site of Woodwardia Falls, a small

waterfall on East Waddell Creek. This is a small cluster of

7 stems ranging from 5 em to 19 em and from 2 m to 9 m in

height.

Site 7 is another elongate area stretching one

kilometer along Berry Creek with a width of about 0.1 km and

ranging in elevation from about 180 m to about 305 m above 32

sea level. The upper portion of this location is chaparral covered with knobcone pine (Pinus attenuata), and the bay trees here are in a small west-facing canyon. There are 4 clusters on either side of the canyon with individuals of

from 6 cm to 15 cm dbh and from 5 m to 10 m tall. Below these clusters, along Berry Creek, there are some 35

individuals (?) (some are multi-stemmed), with widely varying dbh and heights, the smallest being seedlings, the

larger trees ranging up to 35 cm dbh and 10 m tall. This

location is very steeply sloping and contains Golden, Silver

and Berry Creek waterfalls. The vegetation is mostly mixed

evergreen, although there are a few riparian species

individuals such as alder (Alnus rhombifolia) and bigleaf

maple (Acer macrophyllum). This is not a riparian area in

terms of the vegetation.

Site 8 lies along lower Waddell Creek, is about 5 km

long and from 40 m to 200 m wide and ranges in elevation

from 6 m to 65 m above sea level. This is a riparian flood

plain with several hundred individuals from seedlings to

mature trees 60 cm dbh and 25 m tall.

Site 9 is along the west side of Opal Creek in the

park headquarters area. One bay tree was found here growing

in the creek bank. There are a few riparian species

individuals such as alder, but it is not an area of riparian

woodland and there is no flood plain. The creek is incised 33

into the floor of the Basin.

Site 10 is below the park residence area water tanks on a hill above the Sky Meadow residence area. This site is at the head of a bowl-shaped old landslide, in a southwest

facing drainage about 30 m downhill from the water tanks.

There were 24 individuals, the smallest being 5 cm dbh and

1.5 m tall and the largest 20 cm dbh and 7 m tall. 34

TABLE 1

Individuals/Species

Transect

Species BB10 BB5 BB9 BB5A HC1 HC2 HC3 PI p2

Umbel 1 ularia californica 24 1 1 0 27 15 6 4 6

Lithocarpus densiflora 13 7 11 4 21 0 0 12 7

Sequoia sempervirens 10 0 1 15 18 9 0 2 1

Pseudotsuga menziesii 0 3 0 0 2 0 0 1 5

Arbutus menziesii 4 5 0 0 0 0 0 1 5

Quercus agrifolia 6 3 0 0 0 0 0 0 0

Alnus rhombi folia 0 0 1 0 0 0 10 0 0

Acer negundo 0 0 0 0 0 0 43 0 0

Acer macrophyllum 0 0 0 0 0 0 3 0 0

Platanus racemosa 0 0 0 0 0 0 2 0 0

Populus trichocarpa 0 0 0 0 0 0 1 0 0

BB=Big Basin HC=Henry Cowell P=Portola 10, etc.= Site Number 35

TABLE 2

Density *

Transect

Species BB10 BB5 BB9 BB5A HC1 HC2 HC3 PI P2

Umbellularia californica .080 .007 .007 .111 .100 .040 .014 .120

Lithocarpus densiflora .043 .047 .073 .027 .086 .043 .140

Sequoia sempervirens .033 .007 .100 .074 .060 .007 .020

Pseudotsuga menziesii .020 .008 .004 .100

Arbutus menziesii .013 .033

Quercus agrifolia .020 .020

Alnus rhombi folia .007 .067

Acer negundo .287

Acer macrophyllum .020

Platanus racemosa .013

Populus trichocarpa .007

BB=Big Basin HC=Henry Cowell P=Porto1a 10, etc.= Site Number

*Number of individuals per m2 36

TABLE 3

Coverage *

Transect

Species BB10 BB5 BB9 BB5A HCl HC2 HC3 Pl P2

Umbellularia californica

Lithocarpus densiflora

Sequoia sempervirens

Pseudotsuga menziesii

Arbutus menziesii

Quercus agrifolia

Alnus rhombi folia

Acer negundo

Acer macrophyllum

Platanus racemosa

Populus trichocarpa

BB=Big Basin HC=Henry Cowell P=Portola 10, etc.= Site Number

* Percentage of area of transect covered by vertical projection to the

ground from aerial parts of tree. 37

Single Mature tree 20 feet tall, 10 inches dbh

Site 1 38

Ol C N .r-! r-i Q) "0 .jJ Q) or-! Q) C/) C/) Single tree, 10 inches dbh. Bowing of trunk likely caused by snowfall in January 1974. Site 2

W \D 40

Two clusters of 10-12 individuals (?) each, up to 40 crn dbh and 13 rn tall Site 2 41

Looking into Sempervirens Creek Site 3 42

One cluster of 10-12 individuals (?)

2.4 em to 12.5 em dbh, 3 m to 7 m tall

Site 4 43

Single tree, 15 em dbh, 8 m tall

Site 5 HISTORICAL PLANT GEOGRAPHY

There are two main schools of thought regarding the development of the present vegetation and flora in the

Western United States. One conceives of three relatively stable assemblages of plants that had become established by the beginning of the Cenozoic and that migrated more or less as wholes in response to climatic fluctuations (Chaney,

1947; Axelrod, 1958, 1977; Raven and Axelrod, 1977). These three have been termed the Arcto-Tertiary, Madro-Tertiary, and Neotropical Tertiary Geofloras. The Arcto-Tertiary

Geoflora is supposed to have included genera of the coniferous and temperate-deciduous forests, such as Acer, Fraxinus, Fagus, etc., and to have originated in and covered the high latitudes. The Madro-Tertiary Geoflora brought

sclerophyllous and microphyllous vegetation such as

chaparral, and oak woodland, which included Umbellularia and

genera such as Arctostaphylous, Arbutus, Ceanothus, etc.,

north from the semi-arid Sierra Madre of Mexico. The

Neotropical-Tertiary Geoflora was composed of tropical plants of the genera Persea, etc., none of which are extant

today in the Western United States. The modern vegetation

and flora of the Western United States, California and Big

Basin is the result of the geofloras' migrations north,

south, and altitudinally, following climatic changes.

The other interpretation has been expressed by

44 45

writers such as Mason (1947) and Wolfe (1969, 1971, 1975,

1978, 1979), who contend that plant migration and association is accomplished at the level of the individual species as it reacts to and acts upon its environment, rather than many species migrating en masse. This interpretation holds that, "The apparent unit flora or unit floristic element in floristic history is a coincidental aggregation" (Mason, 1947). Hence, we cannot assume that the floristic and vegetational patterns are the same ones as existed in the past.

The search for the center of origin of a particular species, or geoflora, is fraught with gaps in the fossil record, imperfect knowledge of past climates, and imperfect knowledge of tectonics. In fact, there may be multiple centers of origin. Whether the present day vegetation and flora of Big Basin is the result of migrations of geofloras or species and exactly where they came from is outside the scope of this thesis.

Fossils from the Western United States show that taxa of Lauraceae were widespread in the Eocene. Today

Umbellularia californica is the only member of this family which exists in the Western United States, and there only from Southern Oregon south to San Diego County (Chaney,

1947). What the fossil record tells us, generally, is that there have been climatic changes with resulting floristic 46

changes in the present middle latitudes.

The oldest rocks in Big Basin are of Cretaceous age.

During the 65 million years since, Big Basin has been

alternately inundated by and raised above the sea. By the

Middle Oligocene, Big Basin had "a mature landscape cloaked

with subtropical vegetation" (Brabb, 1960). This implies a

warmer, somewhat wetter climate than that of today. At some

time during the Oligocene, the climate became cooler and

drier, eliminating many species from the area. This general

cooling and drying, principally by cessation of summer

precipitation, has continued to the present time.

Few plant megafossils have been found in Big Basin so

there is little direct evidence of the flora that existed in

the area in the geologic past. The redwood fossils that

have been found show Pleistocene ages (Robison, 1948), while

a Lauraceous leaf, possible of the genus Nectandra, was

probably of Eocene age (Bragg, 1960).

As mentioned in Chapter 2, according to Mason, 1947,

Umbellularia as a species probably developed in the middle

to high latitudes at a time when the climate was much more

equable. It is unknown from where its phylogenetic

ancestors came. ECOLOGICAL PLANT GEOGRAPHY

In an effort to determine which, if any ecological factors contribute to the control of the distribution of

Umbellularia, three factors were investigated. These are nutrients, competition and allelopathy, and seed production and dispersal. Review of weather records at Big Basin

Redwoods State Park and review of the Soil Survey of Santa

Cruz County provided information on moisture, insolation, and soil pH. Personal observation that bay and tan oak do not appear to associate in Big Basin pointed to the possibility of competition or allelopathy as a distributional control. Seed amount, size and use as a food by animals were considered as possible explanations of seed distribution and hence tree distribution.

Nutrients

Umbellularia grows on many types of soils "if moisture is constant and plentiful" (Folwells, 1953). It develops and grows best "on deep, well-drained alluvial fills and valley bottoms subject to inundation by high water," while growth is good "on well-watered sedimentary soils of the coastal slopes and along higher foothill streams" (Folwells, 1953). In Big Basin Umbellularia is found on five different soil types (Fig. 10). All of these soil types are predominately of sedimentary derivation, mostly shale and sandstone. The ten sites where

47 48

Umbellularia grows in Big Basin show no common trait of moist soils. The tree has been found there in moist soils along streams as well as in dry soils.

In Henry Cowell bay is prevalent along the San

Lorenzo River and its floodplain. It is less so farther away from the river, but still grows on all soils which had transects across them (Fig. 8). Portola presents a somewhat different picture in that the transects were one soil type only.

Soil moisture from winter precipitation is augmented by drip from summer fogs. Fog also moderates summer temperatures and accompanying evapotranspiration stress

(Unsicker, 1974). This is most true in the lower Waddell

Creek and less so on the floor of Big Basin where the fog may not penetrate for weeks at a time during the summer.

Bay tolerates shade well, and in Big Basin it grows where there is a dense overstory and in open, sunny areas.

The largest trees were found in mixed evergreen forest where bay made up a part of the canopy with the tops exposed to full sunlight, such as Site 2, and in riparian zones along the lower reaches of Waddell Creek.

The same numbers and kinds of other species grow where Umbellularia does as well as in areas where it does not grow. Umbellularia grows on nutrient rich soils and nutrient poor soils, in alluvium and in thin-soiled rocky 49

outcrop.

That tan oak is so common in Big Basin and bay so rare suggested allelopathy or competition as a limiting factor for bay.

A11elopathy and Competition

Many plants exude chemicals that tend to inhibit the growth of other plants, even those of the same species

(Ornduff, 1974). Umbellularia is among these and, when reaching maturity, trees are characteristically free from understory plants. However, if allelopathic influences are active in determining the distribution of bay, they corne from another plant or plants and not from bay itself. In

Big Basin, bay's scarcity gives the initial impression that it and tan oak do not associate. They do occur together outside of Big Basin in the adjacent San Lorenzo River valley, for example (Table 1). Tan oak does have allelopathic properties, especially the tannins which made its bark useful for the hide tanning industry. That tan oak in Big Basin would be allelopathic to bay, yet not so just a few kilometers away over a drainage divide in an area with the same soils and climate, seems unlikely. Also, there is no lack of understory species beneath tan oaks.

Often the effects of allelopathy and simple competition for physical resources may be indistinguishable

(Unsicker, 1974). Competition does not always result in the 50

complete elimination of one species. It may persist in an otherwise suitable environment by vegetative reproduction where competition for resources does not allow for the survival of sexually-produced offspring (Unsicker, 1974).

This may be critical for bay in Big Basin since, with so few mature trees, seed production is very low.

Seed Production and Dispersal

A bay tree will produce large amounts of seeds after it is 30 to 40 years old (Folwells, 1953). It is also a prolific vegetative reproducer and groups of trees may be clones. Umbellularia seeds are relatively large (about 2.5 cm dia.) and heavy. According to Folwells (1953), they are

"distributed by gravity and water, although squirrels and other rodents may" playa small part. At location 2 an

Umbellularia seedling is growing in a redwood stump one meter above the ground some 180 m away from the nearest mature bay. Undoubtedly the seed was transported by an

animal. In the vicinity are several other seedlings. These

could easily have sprouted from seeds transported by gravity

or water. The seeds most likely will not germinate under the parent but will more likely succumb to fungus. They

require transportation and burying for successful

germination (Folwells, 1953). In Big Basin the relative

lack of mature bay trees means few seeds will be produced,

and since there are so few areas of silt deposition and 51

little soil disturbance, bay seeds face severe handicaps to germination and growth.

Of the five sites noted in the Big Basin Redwoods

State Park Natural History Survey File where Umbellularia was found, three were noted from the mid- to late-1950s, one from the mid-1960s and one from the mid-1980s. Most of these are now at least 30 to 35 years old. These presumably are able to produce large amounts of seeds judging by their age alone, yet seedlings are rare.

The ecological factors seemingly most directly related to the lack of Umbellularia are competition from tan oak and the few seed producers, plus the lack of suitably prepared habitats for germination and growth. PHYSIOGRAPHIC PLANT GEOGRAPHY

Physiographic plant geography studies the relationship between landforms and plant distributions "in relation to geomorphic ('physiographic') processes that create the various plant habitats" (Zimmermann and Thorn,

1982). Geomorphic processes which create habitats for

Umbellularia are depositional processes which create alluvial soils having the requisite constant and plentiful moisture that bays need. That bay may be found in other than flood plains, such as on hillside canyons, is due to other than geomorphic processes.

Non-depositional habitats supporting Umbellularia are more likely due to geologic structure and associated availability of water.

Umbellularia grows in the alluvial flood plain soils of lower Waddell Creek. As discussed earlier, the tree is uncommon elsewhere in Big Basin, even along the streams, with the exception of Berry Creek. Thus it was very important to study the streams of Big Basin. Above the junction of East and West Waddell Creeks, there are no current depositional features of more than a few square meters. The streams are entrenched. During six years of personal observation, I have never seen any of the entrenched streams rise over their banks during or shortly after heavy precipitation. Although they are heavily laden

52 53

with silt during the winter, the streams' steep gradient and narrow, deep channels make for rapid transport of the silt downstream below the junction. There the gradient flattens and deposition occurs. Hence, in the greater portion of Big Basin there is a lack of alluvial soil that has constant and plentiful moisture. The alluvial soil that exists along Bloom's and Opal Creeks is the largest area of alluvium on the floor of Big Basin and "is subject to rapid erosion" (McJunkin, 1983). DISTURBANCE FACTORS

No area of the Earth's surface is free from disturbance of one type or another. Evolutionary history graphically illustrates this with ever changing surficial features and forms, fires, and floods. Humans, with mechanical technology, are able to disturb the earth in a wide variety of ways. In Big Basin human and non-human disturbance factors have altered some forest habitats greatly and others only slightly. Probably the most common forms of habitat disturbance in Big Basin are windthrow and mass-wasting. Windthrow

Windthrow usually occurs when a tree is diseased or its root system is destabilized by soil saturation.

Observed windthrown trees have almost always fallen during the winter months during or shortly after heavy rainfall, when there are strong winds. The area disturbed by such events varies greatly depending on the size of the tree, the nature of the surrounding vegetation, and whether the tree broke above the ground or was uprooted. The disturbed area may be only a few square meters at the base of the tree in open areas, or several dozen square meters if the falling tree knocks down other trees. Most of the observed windthrown trees are redwood or Douglas fir and are relatively large, ranging from 50 m to 65 m tall and from

54 55

0.75 m to 1.5 m dbh. Mass-wasting

Mass-wasting involves the rapid downslope movement of rock and soil as in mudflows and landslides. Big Basin has had many such occurrences from the geologic past through the present, usually occurring every winter when soils, and sometimes underlying rock bedding planes become saturated.

The size of such earth movements varies greatly from a few square meters to several square hectares, as at the postulated Middle Ridge landslide (McJunkin, 1983). Mass­ wasting can quickly open up large areas of forest and provide opportunities for species to invade an area.

Snowfall

A rare event in Big Basin, snowfall may have limited disturbance value. The last significant snowfall, in 1974, broke branches and permanently bowed the trunks of countless tan oak and other trees, but did not significantly disturb the forest structure. Fire

Fire has been a recurring phenomenon in Big Basin, as evidenced by fire scars on many of the redwoods and

Douglas firs. Langenheim et ale (1983) have reconstructed the fire history of Big Basin from 1042 to the 1970s. Fire has both human and non-human causes. The non-human cause is lightning, which is relatively rare in Big Basin. The 56

greatest evidence for lightning caused fires is the presence of closed cone pines, such as the knobcone pine, which require great heat to release their seeds. These pines are found on some of the ridgetops and exposed peaks such as

Pine Mountain, which are the most likely places for lightning to strike.

In prehistoric times, besides lightning caused fires, there were fires set by the indigenous people who inhabited the lower reaches of Waddell Creek and other, open spaces outside Big Basin. These fires sometimes were campfires that got out of control and became major forest fires, or were deliberately set fires for the purpose of burning out brush to enhance travel, hunting, and acorn gathering.

Fires, over the centuries, have burned over the entire study area. Their effects have been most severe, and contributed most to disturbance, in the mixed evergreen forest. Old-growth redwood is largely fire resistant due to its thick bark, while chaparral is heavily fire dependent.

Logging

The majority of Big Basin was never logged and the distribution of the flora there is probably very much as was the original (Langenheim et al., 1983). The one wood product activity that did occur on a large scale was the

stripping of tan oak bark from which tannin was extracted 57

for use in tanning leather. There is no physical evidence of this practice, such as stumps, as there would be from logging.

Transect areas at both Portola and Henry Cowell were logged and so represent a disturbed landscape.

Park Development

The latest human-caused disturbance carne, paradoxically, with the creation of the park to preserve the redwoods. Camping and development of facilities associated with it have concentrated human activity within the floor of the basin, led to compaction of soils, and destruction of some less hardy species and seedlings.

None of the disturbance factors appear to be

limiting to the distribution of Umbe~~u~aria. In fact, bay

seems to need soil disturbance or silt deposition to bury

its seeds for successful germination and growth. Areas

outside of Big Basin that have experienced widespread disturbance such as logging generally have much bay, such as

at Henry Cowell. CONCLUSIONS

The primary purposes of this thesis were to document the location and occurrence of Umbellularia californica in

Big Basin and attempt to account for its relative rarity.

There are virtually no bay trees in Big Basin, while other areas of redwood and mixed evergreen forest support large bay populations. This is true in areas such as the San

Lorenzo River Valley adjacent to Big Basin. Initially, the locations of Umbellularia as listed in the Big Basin Redwoods

State Park Natural History Survey File were verified or disproved. Additionally, all areas with potential Umbellularia habitat were field checked, and further general field checking was accomplished by reconnaissance hiking and driving, respectively, on all trails and roads within Big

Basin.

With the establishment of the locations of

Umbellularia several potential controlling factors were investigated in order to arrive at an explanation of the relative lack of bay. Three factors seemed most relevant:

1) ecological factors, 2) landforms, and 3) disturbance factors.

Of the ecological factors, atmospheric and soil nutrients do not appear to playa role in bay's scarcity in

Big Basin. Since there are few mature bays in Big Basin, seed production is necessarily limited. Those seeds that

58 59

are produced and transported away from the parents' allelopathic effects still seem to have a very small chance of germination and growth. Bay seeds need to be buried to successfully germinate and produce viable seedlings. This requires either soil disturbance or deposition of soil over the seed. There are few mechanisms to provide soil disturbance and depositional areas are of very small size and few in number.

Landforms seem to have an influence on the distribution of bay. Few habitats suitable for the growth of bay exist above the junction of East and West Waddell

Creeks. Those landforms most suitable for Umbellularia are depositional features such as floodplains. The floodplain of the San Lorenzo River in Henry Cowell and the floodplain of the lower Waddell Creek both support large numbers of bay trees.

Disturbance factors or their lack may explain why there are so few bay trees in the study area. Indeed, it seems that the lack of ground disturbance may inhibit bay's migration and production of viable offspring. There seems to be an increase in Umbellularia with widespread ground disturbance such as occurs with logging, which did not take place in Big Basin, but which did occur in Henry Cowell where bay is more prevalent, even outside the floodplain of the San Lorenzo River. 60

There is no single factor that can account for the relative lack of Umbellularia californica in Big Basin.

However, three factors stand out in importance: the paucity of bay's seed production; the lack of widespread, severe soil disturbance and the lack of depositional landforms. BiBLiOGRAPHY

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