Redwood Grove is a beautiful 5.7-acre park located on a stretch of Adobe Creek in the heart of Los Altos. The Redwood Grove restoration was launched in December 2009 and is a project of Acterra Stewardship and the City of Los Altos. The project brings community volunteers together to remove invasive plants, install native plants and demonstration gardens, and create habitat — such as birdhouses and brushpiles — for native wildlife. In the process of restoring Redwood Grove to health, Acterra's staff educate participating youth and adults about the park's wildlife and ecosystem.
In the first year of the restoration project, 736 volunteers spent 1,843 hours working at the site. Together, we have cleared over 18,000 square feet of land of Algerian ivy, Himalayan blackberry, giant reed, poison hemlock, and French broom, freed 80 trees of climbing Algerian ivy, and installed 680 native plants under the redwoods and in the new demonstration garden. Over 40 different species of native plants have been installed at the park — these locally native plants support native insects and other wildlife that are specifically adapted to this area.
The main redwood grove suffered from soil compaction and lacked understory vegetation and "duff"-leaf litter and organic material that acts as a mulch layer in redwood forests. Duff feeds nutrients to the soil, insulates the soil from extreme temperatures, and helps to retain moisture. To improve conditions amongst the redwoods, we have planted native redwood understory plants and temporarily fenced the restoration area. The floor of the redwood grove is already less compacted and healthier. The increased plant biodiversity also provides important habitat for native insects, birds, and other animals.
|Algerian ivy forms a carpet over the ground, smothering other growth. Volunteers are pulling out ivy throughout the park and replanting these areas with native plants.|
|The ivy is also climbing up trees, where it competes for sunlight and weighs down branches. Ivy with snake-like trunks of 6-inch diameter have been found climbing to the tops of sycamore trees in the park. These are being cut at the base to kill off the climbing vines, which eventually dry out and drop.|
|Arundo donax, or giant reed, is an extremely fast-growing invasive plant that colonizes streams. Not only does it consume high volumes of water, but its dense growth is also quite flammable. A stand in Redwood Grove was removed by cutting the stalks to the base. A tarp is laid over the remaining biomass to starve it of light; after a year, the tarps will be removed and the area replanted with native riparian species.|
Adobe Creek begins its journey from Black Mountain and flows through Redwood Grove on its way to San Francisco Bay. The channel is relatively flat and sinuous through the park, and regularly floods its banks, depositing nutrients in the floodplain and reducing peak flows downstream.
Over the past several years, a grant from the Santa Clara Valley Water District enabled Acterra to focus on revegetation of creekside areas and the installation of the willow sculpture highlighted above. In addition, we are working to reestablish native plants on Adobe Creek where the City of Los Altos has installed a bioengineering project and reconfigured an old pedestrian bridge in order to address a severely eroding creek bank.
|Habitat brush piles, bird boxes, and barn owl nesting boxes have been installed at the park. Volunteers will help to monitor nesting activity and report results to the local Audubon chapter.|
Restoration work will continue throughout Redwood Grove, including the connection from Redwood Grove to Shoup Park. As our planting areas start to mature, focus is being shifted towards maintenance activities and ensuring that invasive plants are kept in check. We will also continue to expand the growing native meadow area at the Manresa gate.
For further information about this project or to be added to our email info list, contact Kristen Williams, Project Manager, at kristen.williams*acterra.org.