Sunol Field Trip

Local Plant Communities

(Image: Entrance to Sunol - Ohlone Regional Wilderness)


•      All of the organisms of one kind in an area.

•      All of the people in this room constitute a population.


•      The populations of various species  (all the organisms) living in a particular region or habitat.

•      Characterize by the organisms present.

•      Dominant species - influential

•      Most numerous and/or the largest.

•      Often the community is named after the dominant species.

     –    Example - redwood forest

Redwood Forest

•      The trees have a great effect on the community. 

•      They create shade which limits which plants can grow with the redwoods.  They must be shade tolerant.

•      The redwoods are not a good source of food for animals.  This limits the number of animals present.

What determines which community is where?

•      Climate

     –   Light

     –   Temperature

     –   Water

•      Soil

Sunol communities that we will see:

•      Riparian

•      Grassland

•      Oak woodland

(Image: Sunol hills showing dark green oak woodland and light brown grassland)

     •      Note the mosaic of oak woodland (dark green) and grassland (light brown) on the hills.

     •      The dark brown area is coastal scrub.

     •      The trees which are on the right are part of the riparian community.


(Image: riparian community)

•      Streamside

•      From ripa, Latin for stream bank or riparius, growing along bank.

•      Along permanent streams and rivers

•      Has been systematically destroyed by flood control channels, rice paddies.

(Image: riparian community)

•      Typical plants have large leaves.

     –    Large leaves allow for maximum exposure to the sun for photosynthesis.

     –    Most water loss from plants is from the leaves.

     –    In dry areas, large leaves are a disadvantage.

     –    In the riparian community, however, there is a constant supply of water

Riparian Community Along Alameda Creek in Sunol (Image: riparian community)

•      Trees are usually deciduous. (Image: deciduous trees)

     –    They lose their leaves in  the late summer or fall.

•      May be “jungle-like” in summer.

•      Abundant wildlife.  Why?

     –    Cover

     –    Food

     –    Water

•      Plants we are likely to see:

     –    In the water, cattails

     –    On the edge, willows, white alder.

     –    Further back, cottonwood, big-leaf maple, California sycamore. (Image: California Sycamore tree)


•      In the past the dominant grasses were native perennial bunch grasses.

     –   Perennial - lives year after year.

          •   Can be woody like a tree or can come up every year like a tulip.

          •   The grasses came up every year.

     –   “Bunch” - the leaves are in clumps.

•      Replaced by alien, annual, European grasses.

     –   Alien - introduced, not native.

     –   Annual - sprouts from a seed, grows, produces flowers, seeds and dies.  Sprouts the next year from a seed.

•      Hills were green longer with the originals.

•      No shrubs or trees.  Why?

•      Wildflowers in the spring.

Vernal pools

•      Often found in depressions in grassland areas where the water doesn’t drain.

•      Temporary ponds that fill with water in winter then dry up in the spring.

•      May see rings of flowers.

     –   Those closest to the water are the most tolerant of wet soil.

•      Some plants are endemic to vernal pools.

     –   Endemic = found in only one area.

Oak Woodland

(Image: Sunol hills showing oak woodland and grassland communities)

•      Note the oak woodland community in the gullies.

•      Grassland is on the hilltops.

•      Dominant plants are oak trees;

     –    Blue, valley, coast live, interior live. (Image: coast live)

          •    “live” = evergreen

•      In addition to the oaks:

     –    Bull, foothill, or gray pine. (Image: gray pine)

     –    California buckeye

•      Trees may be scattered or be dense.

•      Under the trees, grasses and shrubs.

Use of a key

•      We are going to use a simple key to identify the plants.

•      It is the Pacific Coast Tree Finder by Tom Watts. (Image: Pacific Coast Tree Finder)

•      Your instructor will lend you a copy.

•      If you are interested in buying it, you can order it from or Sunrise Mountain Sports in Livermore usually carries it.  It costs about $3.50.

(Image: Students using a key to identify plants)

•      Begin on page 6.

•      Read the two alternatives and select the one which applies.

•      Go to the page and the symbol specified.

•      Continue reading the two alternatives and selecting the best until your arrive at the name of the plant.

Names of organisms

•      Common names and Latin names

     –   Problems with common names:

          •   A plant may have more than one.

          •   Will vary with the language of the speaker.

          •   The same name may be used for two or more plants.

•  Latin names consist of a genus name and a species name.

•      How they are correctly written:

•       Pinus sabiniana or Pinus sabiniana, gray or foothill pine.


•      Read the handouts prior to the field trip.

•      Bio 31 - Read pp. 6-8, 566-567, 686-687, 726 in Mader.

•      Bot 1 - Read pp.53-69 in the Supplement before the trip.  Pp. 53-54 explain what you are going to do.  Read 219-221in the text, online 31-1, 32-2 to 32-8, 32-16 to 32-17, 32-20 to 32-21.

     –    You will have to turn in a field report, if you are in Botany 1

     –    The report will be due one week from the date of the trip.

What to Bring:

(Image: Students appropriately outfitted)

•      Flat shoes

•      Long pants

•      Water

•      Sun screen, hat

•      Insect repellant

•      Something to take notes on/with.

Watch out for this plant!

(Image: poison oak)

•      This is poison oak. 

•      Note the three leaflets which make up the leaf.

•      Many people have allergic reactions to the oil which it produces.

•      If you come in contact with the leaves or branches, wash with cool water and soap as soon as possible.


•      Handouts

     –   Get them from your instructor and read them prior to the trip.

•      A map is included in your handouts.

•      Meet at the barrier in the road near the porta-potties.

•      Time - your instructor will specify.

Visitor Center

(Image: Sunol - Ohlone Regional Wilderness Visitor Center)

•      Check out the recently renovated Visitor Center before you leave.