Joe Cannon: The Man, The Myth, The City College Professor

Publisher: City College Center for Habitat Restoration
Reporter: Caroline Christman

I took an hour one Thursday to talk to one of City Col-
lege's newest professors, Joe Cannon. Not only is Mr. Can-
non teaching classes here in ecology and botany, he is also
managing a project on San Bruno Mt. called the Colma
Creek Restoration Project. Joe's botany students have al-
ready visited and worked on this project. Most exciting of
all, anyone can be a part of the restoration of Colma Creek
by volunteering with the Heart of the Mountain group; their
program meets on the second and fourth Saturday of every
month from 10:00am to 12:30pm. Find out more by visiting

Interview with Joe Cannon
Caroline: When did you start working at City College?
What inspired you to become a professor here?
Joe: I started here in Spring of 2004. I first started working
in habitat restoration at the Presidio, at the time I wanted
to save the environment. It quickly became clear to me that
the problem was people. Habitat restoration was a vehicle -
helping nature and changing people's relationship to nature.
Education is the most direct way to address people's rela-
tionship with nature.

C: The ecology program at City College is small; do you
plan on introducing any new classes? Do you have a vision
for the future of an ecology or environmental science pro-
gram here?

J: Crima (Pogge) and I are going to a conference at De Anza
Community College to learn about creating environmental
studies programs. They have a pretty good program there;
they also have a pretty good program at Merritt College.
It's pretty amazing that City College has no program; this
will hopefully change.

C: You have many years of experience with habitat restoration,
what are some of the most positive events and some
of the most challenging events in which you have taken

J: The most positive event is the change I've seen in people's
lives that is due to volunteering (in habitat restoration
programs); volunteers develop a new relationship with the
environment. People show up for one program, and even-
tually they change careers and invest fully in habitat restora-
Also, things like the Presidio Native Plant Nursery had a lot
of bureaucratic resistance and many obstacles to program
growth, but some people such as Sharon Farrell and Pete
Holloran and myself had a vision for the program and
persisted, and it is now a large and well-established pro-
gram. There was also a lot of resistance from the public
to any land use change in the Presidio, which was very
challenging; and the National Park Service (NPS) often
resisted active restoration because it was too controver-
sial, too expensive. The NPS also put up a lot of resis-
tance to volunteers. They thought volunteers would dam-
age native plants and endangered species. They didn't
appreciate that volunteers could contribute a lot of ex-
pertise and knowledge. Now volunteers make up most of
the work force in the Presidio!

C: Where did you first begin working on habitat restora-
tion? Who did you work with? Did you have a mentor?
What did you learn from them?

J: I first worked on the Mission Blue Butterfly Project in
the Marin Headlands and on Milagra Ridge. I worked with
Sue Gardner, but she left almost immediately to start the
Site Stewardship Project, which she still runs. I took over
Mission Blue project and worked for 6 months to
finish the initial 3 year project. Site Stewardship now
works at those Mission Blue sites. Actually, it was soon
after this that City College adopted Wolf Back Ridge.
If anyone was a mentor to me it was Sharon Farrell, she
taught me a lot about working with people and the im-
portance of volunteers. She helped me move from a pure
science perspective to involving people in restoration.

C: I've heard rumors that a native plant garden is going to
be started on campus.

J: Our first project is going to be a primitive plant garden in
one of the bays on the East side of the Science Hall. This
has lots of teaching value for botany classes. A native plant
garden is a goal for the future, it may be in the second of
the Science Hall bays or, ideally, on this steep slope on
campus that is not slated for development. Volunteers have
been working there for years and the plan is to get a com-
munity-based botanical garden started there. That way stu-
dents can go out to the primitive garden and the native plant
garden and see the things we're talking about in class.

The Colma Creek Restoration Project
Colma Creek is located on the northern portion of San
Bruno Mt. on San Mateo County and CA State Park land.
This riparian corridor is one of the few remaining relatively
intact on the San Francisco Peninsula, with an area of ma-
ture willow forest along the upper East arm of the Creek.
Riparian areas, along with marshes, are important stop over
points for many birds that migrate along the Pacific Flyway;
they are also home to innumerable plant and animal species
year-round. The Colma Creek area is a favorite spot for
birders and hikers because of the wildlife diversity.

Heart of the Mountain, a volunteer group started by Pete
Holloran of the California Native Plant Society (CNPS), has
been working to control non-native invasive plants in this
area for several years. The group has been successful in
involving many people from the neighboring communities in
habitat restoration. Now, with funding from Proposition 40,
more extensive work can be done. The Colma Creek Restoration
Project is being coordinated by Joe Cannon and
sponsored by The Watershed Project, a non-profit organi-
zation, will involve removing blue gum eucalyptus trees
(Eucalyptus globulus) and other non-native plants along the
headwaters of Colma Creek and replacing them with native

The first phase of the project will be tree removal and re-
moval of large patches of Himalayan blackberry (Rubus dis-
color), English ivy (Hedera helix) and Cape ivy (Delairea odo
rata); this will be performed by San Mateo County Fire
Crews. Volunteers will be involved in removing smaller
patches of non-native plants, following-up on ivy and black-
berry removal, and planting native plants grown at the
Friends of San Bruno Mt. Mission Blue Nursery (a San
Mateo County-sponsored group that does restoration on
San Bruno Mt) or at the Fort Funston Nursery (part of the
Golden Gate Recreational Area). The project goal is to
enhance this riparian area for wildlife and to create an uninterrupted
corridor from the headwaters of Colma Creek
down to Guadalupe Canyon Parkway.

One important aspect of the project, and one of the stated
project priorities, is that it will involve volunteers in weed-
ing, planting, and growing plants in the nurseries, and will
provide educational programs to foster knowledge of native
plants and ecosystem function. Volunteers will not be in-
volved in tree removal, but will be removing Himalayan
blackberry, cotoneaster (Cotoneaster pannosa), Cape ivy,
English ivy, sheep sorrel (Rumex acetosella), purple velvet
grass (Holcus lanatus), poison hemlock (Conium maculatum),
mustard (Brassica nigra), wild radish (Raphanus sati-
vus), and bull thistle (Cirsium vulgare). Addition-
ally, the Heart of the Mountain volunteer pro-
gram will continue to work on controlling other pioneer
populations of thes targeted invasive species.

Eucalyptus Removal

Why do the eucalyptus need to be removed to restore this
rare and valuable habitat? Eucalyptus trees are growing
along the headwaters of Colma Creek, which disturbs this
riparian ecosystem in several important ways. Eucalyptus
grow quickly and can form dense stands in areas with
enough moisture, such as along a creek or in an area with
fog. They are allelopathic, producing chemicals that can
retard germination of many seeds and inhibiting growth of
other species. Additionally, eucalyptus release oils that
coats the soil making it hydrophobic, or unable to absorb
water. In the shade beneath the eucalyptus you will not find
the native plants that usually grow on the forest floor in
California, rather, other invasive plants such as English ivy,
Cape ivy and Himalayan blackberry dominate this area.
Most native plants cannot tolerate the conditions below the
eucalyptus because of the shade, the oils, and the change in

The change in hydrology is the most important factor in
this restoration project. Eucalyptus achieve great height
very rapidly, they accomplish this by competing successfully
for available moisture. They have both a deep tap root and
a layer of intricate surface roots, this allows them to absorb
water from the soil as it rains or as their leaves collect and
drip fog, and their tap root can tap into the water table,
especially where it is close to the surface along creeks. This
means that much of the water that would be in the soil, in
the creek or in other plants and animals is instead being
used by the eucalyptus. Also, they are large and lose more
water to transpiration than a smaller tree; this is water that
would otherwise flow into the water table or the creek.
Much research has been done on eucalyptus water use and
have shown that eucalyptus reduce water yields in an area
and use more water than most other trees, which in turn
means that less water is able to reach Colma Creek and the
wildlife that depend on the creek.

The Colma Creek Restoration Project will remove about 3
acres of eucalyptus and non-native understory plants from
areas adjacent to Colma Creek. This will be done after
bird-nesting season (March15-Aug 15) to ensure that no
nests are destroyed. Eucalyptus stumps will be cut and
painted with herbicide to keep them from resprouting. Silt
fences and weed-free straw will be used to control erosion
during the first few rainy seasons. These cleared areas will
then be replanted with natives to form several different
plant communities.

Planting Natives
The primary plant community that will be established in the
areas up slope away from the creek channel will be coastal
scrub, with dominant plants such as California sagebrush
(Artemsia californica) and coyote brush (Baccharis pilularis),
this area will also have patches of grasses such as blue wild
rye (Elymus glaucus) and herbaceous plants such as gum
plant (Grindelia hirsutula) and coyote mint (Monardella vil-
losa). Mature coastal scrub forms dense cover and will dis-
courage reinvasion of the area by non-native invasive plant
species. Rushes (Juncus patens, J. phaeocephalus, J. balticus,
etc.) and sedges ( Carex densa, C. obnuta, C. subbracteata,
etc.) will be planted along the creek with small trees such
as pacific wax myrtle (Myrica californica) and American dog-
wood (Cornus sericea ssp. sericea) and herbaceous plants
such as seep monkeyflower (Mimmulus guttatus) on the
banks. A wet meadow area will be recreated above the
road using, grasses such as California oat grass (Danthonia
californica) and meadow barley (Hordeum brachyantherum).
Native annual species will be directly seeded on to the restoration

Where will nurseries get the seeds for propagation? Native
seed has been collected by the dedicated volunteer Leroy
French and by the Heart of the Mountain volunteers. Seeds
are all collected on San Bruno Mt., and from within the
Colma Creek watershed as much as possible. Collecting
seeds in this area ensures that the plants are adapted to
local conditions. To protect resources, no more than 10%
of the seeds from any 1 population or individual plant are
collected in a season. Some plants that spread using root-
like structures called rhizomes can be divided at the base;
most of the plant is left intact in the soil, a small part is re-
moved to the nursery and grows there until it can be
planted during the next rainy season. For plants such as
rushes and sedges this is much easier than collecting seed.
All of the plants need to be planted during the winter and
early spring when it is raining so that they can become es-
tablished before the dry summer months.

The Colma Creek area of San Bruno Mt. is truly beautiful
and teeming with wildlife. Volunteering on this project
would be a great way to learn about native plants and the
wildlife found in a riparian corridor, from salamanders to
migratory birds. To find out more about how to volunteer,
visit: .