The RCD is currently involved with several projects that involve the importance of native and non-native vegetation management in Yolo County.  Our revegetation specialist, John Reynolds currently serves as program manager of one such project,  a Caltrans-funded program involving the planting of native trees, shrubs and bunchgrasses at several local freeway interchanges along I-80 between Davis and West Sacramento.  When in the vicinity of Webster Ave. or Enterprise Blvd., (just west and east of the causeway) or Reed Avenue, and the 80/50 interchange in West Sacramento, you may see the project sites. Over time, this project should result in an attractive yet hardy planting, more able than ornamentals to survive drought, fire, flooding, and insect damage.

This project is a result of a cooperative agreement between the Yolo County RCD and the California Department of Transportation (Caltrans).  The projects plans specify that all plantings will occur in rows, with mulch for weed control laid among the trees.  Most installation occurred in January 2006, and the project passed into a 3-year Plant Establishment phase as of June 2006.  The project was designed to allow Caltrans Landscape Maintenance personnel to continue the mowing program between the planted rows, even after the Yolo County RCD hands over the project in June 2009.  The mulch suppresses weeds around the trees, keeping all mowing activity a safe distance from the vulnerable saplings.  The Yolo County RCD will, for the length of the Plant Establishment phase, also use herbicides to control unwanted vegetation among the planted rows.  Weeds such as Johnsongrass and Field Bindweed commonly push through the mulch, and this requires occasional spraying.

The Yolo County RCD irrigated the plantings May-October of 2006, and will continue summer irrigations through the Plant Establishment phase.  With the exception of one site connected to an irrigation system already in place, all sites are irrigated from a water trailer.  The trailer connects to a buried 1” PVC main line, which then connects to polyethylene hose.  Each tree or shrub receives two 1 gallon-per-hour emitters and each deergrass receives one emitter of the same rating.  The water source is a hydrant belonging to the City of West Sacramento.  Though there is some cost associated with the hydrant permit, the water is clean and project staff experience very few clogged emitters as a result.

During the first year, the deergrass at most sites grew rapidly, and currently they are the most notable component of the plantings.  Some Black Walnut and Cottonwoods are over 6 ft. in height and self-supporting.  The Valley Oaks, also 6 ft. tall at several sites, are slender and some still require staking for support.  Live Oaks, Red and Black Willows, Western Redbud, and Coyote Brush though typically shorter than those mentioned above, are also growing well.  All trees and shrubs, when planted, were supported with bamboo stakes and protective tubes.  With little pressure from herbivores at these urban interchanges and most trees self-supporting, RCD staff removes these structures when no longer necessary.

Despite challenges such as flooding, compacted soils, vandalism, rodent damage, record-breaking summer heat, and errant vehicles, project staff planted over 1,100 trees & shrubs, and 850 plugs of bunchgrass during the first phase from October 2005 - November 2006. First-year survival was  over 88% for the trees and shrubs, and 93% for the native deergrass. The Yolo County RCD looks forward to a continuation of productive growth for these hardy species during the next two-year Plant Establishment phase of the project.

For more information, please contact John Reynolds at 530-662-2037 ext. 121.