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November 20, 2008
Tamarisk Survey in the Sisquoc River
Watershed is Nearly Complete
ForestWatch Volunteers Complete the First Step in Rescuing This
Pristine Watershed from a Devastating Invasion
In October and November,
ForestWatch volunteers spent a total of six days along a remote
portion of the Sisquoc River, deep in the San Rafael Wilderness
of the Los Padres National Forest. We braved hot temperatures,
steep descents, and lots of mud, but our work was ultimately a
success. By the time we reached our destination at Schoolhouse
Camp, our volunteers had trekked more than 27 miles, pulled
hundreds of tamarisk seedlings from the river banks, and
recorded the precise locations of nearly 200 mature tamarisk
plants - the first step in ultimately eliminating tamarisk from
this otherwise pristine watershed.
 Tamarisk
was sold as an ornamental plant in the 1800s and 1900s. Mature
tamarisk trees can produce millions of tiny seeds that easily
disperse through wind and water, and these seeds quickly escaped
from gardens and started taking over the banks of streams and
rivers across the West. Tamarisk grows rapidly and can reach heights of twenty
feet, and its taproot can extend more than one hundred feet
underground.
 Our
tamarisk removal project on the Sisquoc River began in Spring
2008, when we set out to eradicate tamarisk from an eight-mile
stretch of the river. But we ended up finding so many tamarisk
plants that by the end of
our trip, we had only covered three short miles! Each time we
found another tamarisk, we
had to dig it out by the roots so that it would not resprout -
this sometimes required digging in rocky soil up to two feet
deep, making for very slow progress.
Then, we learned about tamarisk
invasions in the Santa Ynez River watershed and the Piru Creek
watershed, among others. Clearly, tamarisk was beginning a
full-scale invasion of the Los Padres National Forest, and we
would not be able to keep up with it at our current pace.
This summer, ForestWatch urged the
U.S. Forest Service to embark on a forest-wide evaluation of how
best to treat tamarisk infestations in these key watersheds. We
also offered to assist the agency in any way possible, and to
that end, we launched our volunteer-based tamarisk survey of the
Sisquoc River in the fall. Our goal was to use electronic GPS
units to record the precise locations of all mature tamarisk
plants. This data would give us, and the Forest Service, a full
understanding of the extent of tamarisk in the Sisquoc River
watershed, and would help us identify the most effective method
to stop the invasion. We'll also be able to easily locate the
plants on our next return visit, when we deliver each tamarisk
plant its ultimate demise.
Upper Sisquoc Survey
In mid-October, with the support
of the U.S. Forest Service, a team of eight ForestWatch
volunteers met atop Sierra Madre Ridge and steeply descended
down to the Sisquoc River at Sycamore Camp.
Over the next three days, we
covered more than 12 river miles, pulling small seedlings and
marking the larger mature tamarisk plants we found along the
way. We were pleased to only find about a dozen mature plants
along this upper part of the watershed.
Our Upper Sisquoc volunteer
crew. Lower
Sisquoc Survey In
mid-November, another team of eight ForestWatch volunteers again
assembled atop Sierra Madre Ridge, dropping down into the
Sisquoc River canyon early in the morning. This time, when we
arrived at the river, we headed downstream instead of upstream.
Tamarisk was much more prevalent along the lower reaches of the
river - after surveying 15 miles of the river, we had found
nearly 200 mature tamarisk plants, along with several more
infestations that were just starting to take root.
Our Lower Sisquoc volunteer crew.
What's Next
ForestWatch is currently compiling
the data that our volunteers gathered, and will present this
data to the Forest Service in the coming weeks. Before approving
any treatment methods, the Forest Service must complete the
required environmental studies, a particularly important step
given the sensitive habitats located along the Sisquoc River.
Once the studies are completed, the agency will approve a plan
of attack. ForestWatch will continue to lend volunteers to this
effort in hopes of eliminating tamarisk from these watersheds
for good. Thank you, volunteers! |
