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May 2005
California Oak Report
Socal National Forests Planning Update
The Forest Service is in the process of preparing the final environmental impact statement (EIS) for the four southern California national forests, the Angeles NF, Cleveland NF, Los Padres NF and San Bernardino NF. The EIS planning revisions will govern forest management for at least the next 15 years.
The EIS indicates Forest Service appreciation of the biological attributes of oak woodlands and acknowledges their responsibility to maintain and restore oak habitat on public lands. A reflection of agency intent is the designation of Black oak, Blue oak, Engelmann oak and Valley oak as "Management Indicator Species" (MIS). It is rare, but appropriate in this case, for plant species to receive MIS status. MIS classification means oak habitat monitoring/evaluation criteria are specific and the resource policy goals clearly defined.
Underlying MIS designation is the fact that the Socal national forests lack Black, Blue, Engelmann and Valley oak advanced regeneration (saplings), making the future viability of many oak stands problematic. Key to the monitoring program is determining to what degree oak regeneration is at risk from domestic livestock grazing, particularly in the Los Padres NF. The following oak woodland information is taken from the Forest Service draft EIS:
Southern California Land Management Plan Revisions DEIS
Desired Condition: The desired condition is to retain existing oak woodlands and savannas. Future management in oak woodlands and savannas prevents the conversion of these savannas and woodlands to annual grasslands or other non-oak vegetation.
Monitoring and Evaluation: Every five years monitor tree mortality in mapped areas of blue oak, valley oak and Englemann oak savannas that are likely to convert to grasslands in the next 15 years because there is inadequate recruitment of saplings into the tree layer. Target areas in which constant losses are occurring for management intervention and restoration.
Oak Woodlands, Savannas and Grasslands
The principal tree species in southern California are generally 16 to 49 feet (5 to 15 meters) in height and include coast live oak, blue oak, Engelmann oak and valley oak. Canyon live oak and black oak occur in some areas, but these species are primarily in lower montane, montane and mixed evergreen forest habitats. Oak savannas commonly contain valley oak on the Los Padres National Forest and Engelmann oak on the Cleveland National Forest, with coast live oak occasional throughout southern California in coastal areas. Coast live oak is the most dominant species in oak woodlands of the western Santa Lucia Ranges and western Transverse Ranges. In San Diego County it occurs with Engelmann oak, and on interior slopes on the Transverse and Santa Lucia ranges it occurs with blue oak and valley oak.
Habitat loss due to urban development has been the major threat to Engelmann oak on private lands making populations on the Cleveland National Forest essential to the conservation of this species. In the case of valley oak woodlands a combination of urbanization, agricultural conversion and poor to non-existent natural regeneration has imperiled this habitat type throughout the State. It is expected that some areas of oak woodland and savannas, especially in Engelmann oak, valley oak and blue oak that are dominated by large, old trees with little or no natural regeneration will begin to convert to annual grasslands as old oaks die without replacement.
Many of the oak woodland and savanna habitats on National Forest System lands are within livestock grazing allotments. Grazing allotments are particularly common in oak savanna types, and they encompass 60% of Engelmann oak woodlands and 87% of blue oak woodlands. Livestock grazing is concentrated in areas where forage and water are abundant. This means that oak woodland, savanna, other grasslands and riparian habitats are areas of concentrated use by livestock. Approximately 65,004 acres of oak woodland, savanna and grassland are found within grazing allotments of the total area of 163,080 acres in this habitat group.
Livestock grazing has been shown to reduce the survival of oak seedlings in some locations, while in others grazing did not affect oak seedling survival or density. With few exceptions, studies did not define the type of grazing occurring in the study sites. This makes a clear assessment of grazing impacts extremely difficult. Research in this area is needed to investigate the long-term relationships among differing grazing management strategies (season, timing, duration, stocking rates) and the effects on seedling survival, sapling recruitment to tree status and long-term dynamics of oak woodlands.
Management Indicator Species
Management indicator species (MIS) are selected because their population changes are believed to indicate the effects of management activities and to serve as a focus for monitoring.
Blue oak, Engelmann oak and Valley oak
These oaks are selected as MIS for the oak woodland/savanna vegetation type. Lack of oak regeneration has been identified as a problem in this vegetation type, attributed to livestock grazing, competition from nonnative annual grasses and unnatural abundance of some acorn-eating animals such as gophers and ground squirrels. Monitoring abundance of these oak species, particularly saplings, will indicate whether Forest Service management has been successful in creating conditions favorable for oak regeneration and, consequently, in maintaining this habitat type.
There are about 33,469 acres of blue oak woodland on the Los Padres National Forest, with a small amount (205 acres) found on the Angeles National Forest. Engelmann oak inhabits the smallest natural range of any oak species in California and is located next to the fastest growing urban landscape in the country. Engelmann oak occurs in limited areas on the Angeles and Cleveland National Forests, with 1,749 acres mapped on the Cleveland National Forest.
Black oak is another MIS for montane forest habitats. Black oak is a gap-phase species that requires occasional openings in the forest canopy in order to regenerate. Abundance of black oak, especially saplings, will indicate progress toward reducing forest stand densities and creating regeneration opportunities for light-requiring species. There are about 10,404 acres of black oak woodland and forest mapped on the National Forests of southern California (1,096 on the Angeles National Forest; 1,621 on the Cleveland National Forest; 194 acres on the Los Padres, and 7,493 on the San Bernardino National Forest). The species occurs as a component of ponderosa pine and mixed conifer forests on many more acres as well.
Message From CDF Urban & Community Fire Protection
Did you know that California has a "Big Tree Register"... one that provides an opportunity to locate trees of significant size? We are looking for those with a sharp eye and interest in big trees to help locate our heritage stock. If you have knowledge of a special tree that you believe is the largest of its kind within California...visit the CA Big Tree Register to see if you might be a heritage tree locator. For more information, see: http://www.ufei.org/bigtrees/bigtreelist.lasso
Merchandise
The Oak Woodland Bird Conservation Plan by Dr. Steve Zack, published by COF.
California oak woodlands rank among the top three habitat types in North America for bird richness. This book is a guide for conservation policy and action on behalf of oak woodland habitats and wildlife. 126 pages. Paperback, $12.00, (members $10.80) plus sales tax, shipping and handling.
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