Sierra Foothill Research Articles

Forage seeding in rangelands increases production and prevents weed invasion

Increasing forage productivity in the Sierra foothill rangelands would help sustain the livestock industry as land availability shrinks and lease rates rise, but hardly any studies have been done on forage selections. From 2009 to 2014, in one of the first long-term and replicated studies of seeding Northern California's Mediterranean annual rangeland, we compared the cover of 22 diverse forages to determine their establishment and survivability over time. Among the annual herbs, forage brassica (Brassica napus L.) and chicory (Cichorium intybus L.) proved viable options. Among the annual grasses, soft brome (Bromus hordeaceus) and annual ryegrass (Lolium multiflorum) performed well. However, these species will likely require frequent reseeding to maintain dominance. Long-term goals of sustained dominant cover (> 3 years) are best achieved with perennial grasses. Perennial grasses that persisted with greater than 50% cover were Berber orchardgrass (Dactylis glomerata), Flecha tall fescue (Lolium arundinaceum) and several varieties of hardinggrass (Phalaris aquatica L., Perla koleagrass, Holdfast, Advanced AT). In 2014, these successful perennials produced over three times more dry matter (pounds per acre) than the unseeded control and also suppressed annual grasses and yellow starthistle (Centaurea solstitialis L.) cover.

Sierra Foothill REC: Quantifying IPM benefits in rangeland systems

News from the RECs Sierra Foothill REC: Quantifying IPM benefits in rangeland systems T here’s a strong scientific case that integrated pest management strategies for rangeland weeds are effective — yet adoption of these practices on rangeland is extremely low. How come? One likely reason, says Jeremy James, director of Sierra Foothill Research and Extension Center (SFREC), is that it’s unclear whether investing in reducing weed populations makes financial sense. Microsoft, ESRI 174 CALIFORNIA AGRICULTURE • VOLUME 70 , NUMBER 4 Elena Zhukova running a series of experi- ments at SFREC. Beginning in 2013, the team manipulated pastures to have different degrees of weediness, measured by the percentage of land infested with medusahead, a com- mon rangeland weed. After 3 years, they had developed Medusahead (in green, above) is an a series of 13 experimental aggressive invasive annual grass that is 5-acre paddocks, with me- unpalatable to livestock for most of its “We have a good idea that invasive plants have negative dusahead coverage ranging life cycle. ecological impacts — but what we surprisingly do not know is from 11% to 50%. if there is actually any economic cost of having weeds on range- This spring, the researchers stocked the pastures with steers lands,” James said. from March through May and evaluated how weight gain var- A national assessment of rangeland integrated pest manage- ied with weed coverage. ment strategies like Results from this first season of tests indicate that weight targeted grazing, seed- gain does indeed suffer as weediness increases: for every N ing of desirable plants, 10% increase in weed cover, total weight gain was reduced by prescribed fire and the roughly 30 pounds per acre — a reduction in market value of use of selective herbi- $30 to $50 per acre at current prices. cides found abundant “For beef cattle production, those numbers are right in the evidence that these prac- middle of being something that might pencil out to treat,” said tices work (Sheley et al. James. “They’re not going to cause ranchers to go out of busi- 2011). However, the same ness, but at the same time they’re not negligible.” study also found that The study is scheduled to continue for at least another 2 that these practices are years. The team will replicate the spring grazing study and also little-used — in part be- assess the effects of weeds at other times of year, James said. cause of the difficulty of The project is part of a collection of studies funded by the assessing their economic U.S. Department of Agriculture that aims to quantify the value benefit. of the many ecosystem services that rangelands can provide. To better understand Some of these, like the effect of weeds on cattle weight gain, can the economic case for be directly quantified in economic terms. Others — such as the weed management, provision of habitat to support biodiversity or the benefits that James and a team of healthy soil can provide for groundwater infiltration — may be researchers — including more difficult to value but may still be desirable for ranchers to Tehama County live- support. The overall goal of the project, James said, is to docu- stock, range and natural ment the full suite of benefits that investments in rangeland resources advisor Josh management can deliver. c Paddock borders Davy, Stanislaus County — Jim Downing range and natural re- sources advisor Theresa Becchetti, Shasta County Reference livestock, range and Meters Sheley RL, James JJ, Rinella MJ, et al. 2011. Invasive plant management on antici- natural resources advi- pated conservation benefits: A scientific assessment. Chapter 7. In: Briske DD (ed.). The 13 test paddocks (nine of which are Conservation Benefits of Rangeland Practices: Assessment, Recommendations, and sor Larry Forero and UC shown here) enclose 5 acres each and Knowledge Gaps. US Department of Agriculture, Natural Resources Conservation Davis Plant Science pro- are infested with medusahead to varying Service. bit.ly/2c1H0s2. degrees — from 11% to 50% coverage. fessor Emilio Laca — are

Ferrisia gilli(Hemiptera: Pseudococcidae) Transmits Grapevine Leafroll-Associated Viruses

Several mealybug species are vectors of grapevine leafroll-associated viruses (GLRaV), which cause the economically important grapevine leafroll disease in grape-producing regions worldwide. The mealybug Ferrisia gilli Gullan is a new pest of grapevines in El Dorado County, located in the Sierra Foothill wine-growing region of California. GLRaV species 1, 2, 3, and 4LV have been detected in vineyards with symptomatic vines in the Sierra Foothills. We conducted controlled virus acquisition and transmission experiments using source vine accessions infected with different combinations of GLRaV. We determined that F. gilli acquired GLRaV 1, 2, 3, and 4LV, and transmitted GLRaV-3 and GLRaV-4LV to uninfected recipient vines. Like numerous other mealybug species, in addition to causing direct damage to vines, F. gilli poses a threat to the grape industry as a vector of economically damaging viruses.

Topographic and Geologic Controls on Soil Variability in California's Sierra Nevada Foothill Region

Author(s): Beaudette, DE; O'Geen, AT | Abstract: We evaluated the feasibility of quantitative soil mapping in two catenas established on different lithologies (metavolcanic and granitic) in the Sierra Foothill Region of California. Indices of landform and microclimate were extracted from a 1-m elevation model. Variation in soil character (clay content, pH, color, cation-exchange capacity [CEC], and Feo/Fed) was partitioned across variables associated with terrain shape and microclimate, lithologic variability, and sampling depth. The potential for using digital elevation models (DEM)-derived indices of terrain shape to predict spatial patterns in soil properties varied greatly between our two experimental catenas. Terrain shape accounted for 4% (metavolcanic site) to 30% (granitic site) of variance in soil properties, while lithology accounted for 14% (metavolcanic site) to 22% (granitic site) of variance in soil properties. Sample depth accounted for 3% (metavolcanic site) to 12% (granitic site) of variance in soil properties. At the metavolcanic site, variability in lithology contributed more to soil variation than terrain shape, which makes digital soil modeling efforts a challenge in these regions. Up to 66% of the variance in soil properties was explained at the granitic site when considering terrain, lithology, sample depth, and associated interactions of these variables. Variance proportions can provide insight into the relative importance of soil-forming factors and is a useful tool when evaluating the efficacy of digital soil mapping projects.

A new perspective on trait differences between native and invasive exotic plants: reply.

EcologyVolume 96, Issue 4 p. 1152-1153 Comment A new perspective on trait differences between native and invasive exotic plants: reply A. Joshua Leffler, A. Joshua Leffler Forage and Range Research Laboratory, USDA-ARS, Logan, Utah 84322 USA. Present address: Department of Biological Sciences, University of Alaska–Anchorage, Anchorage, Alaska 99508 USA. E-mail: jleffler@cc.usu.eduSearch for more papers by this authorJeremy J. James, Jeremy J. James Eastern Oregon Agricultural Research Center, USDA-ARS, Burns, Oregon 97720 USA. Present address: Sierra Foothill Research and Extension Center, Browns Valley, California 95918 USA.Search for more papers by this authorThomas A. Monaco, Thomas A. Monaco Forage and Range Research Laboratory, USDA-ARS, Logan, Utah 84322 USA.Search for more papers by this authorRoger L. Sheley, Roger L. Sheley Eastern Oregon Agricultural Research Center, USDA-ARS, Burns, Oregon 97720 USA.Search for more papers by this author A. Joshua Leffler, A. Joshua Leffler Forage and Range Research Laboratory, USDA-ARS, Logan, Utah 84322 USA. Present address: Department of Biological Sciences, University of Alaska–Anchorage, Anchorage, Alaska 99508 USA. E-mail: jleffler@cc.usu.eduSearch for more papers by this authorJeremy J. James, Jeremy J. James Eastern Oregon Agricultural Research Center, USDA-ARS, Burns, Oregon 97720 USA. Present address: Sierra Foothill Research and Extension Center, Browns Valley, California 95918 USA.Search for more papers by this authorThomas A. Monaco, Thomas A. Monaco Forage and Range Research Laboratory, USDA-ARS, Logan, Utah 84322 USA.Search for more papers by this authorRoger L. Sheley, Roger L. Sheley Eastern Oregon Agricultural Research Center, USDA-ARS, Burns, Oregon 97720 USA.Search for more papers by this author First published: 01 April 2015 https://doi.org/10.1890/14-1962.1Citations: 4 Present address: Department of Biological Sciences, University of Alaska–Anchorage, Anchorage, Alaska 99508 USA. E-mail: jleffler@cc.usu.edu Present address: Sierra Foothill Research and Extension Center, Browns Valley, California 95918 USA. Corresponding Editor: D. C. Laughlin. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume96, Issue4April 2015Pages 1152-1153 RelatedInformation

Diagnostics in animal health: How UC helps exclude and minimize impact of livestock pathogens

UC has a wide reach in the agriculture sector of the California economy and is well recognized for research expertise in plant diseases. Less well known is the role UC plays in animal agriculture. In 2012, the California Animal Health and Food Safety lab at UC Davis performed nearly 980,000 tests on samples from sick livestock, including cattle, horses, pigs, chickens and turkeys. The lab is prepared to respond rapidly to any disease outbreak or identification of a foreign disease. Researchers at the School of Veterinary Medicine at UC Davis are testing novel subunit vaccines to prevent pinkeye in cattle; UC ANR specialists and advisors and the staff at the Sierra Foothill Research and Extension Center were key to the development of best management practices that landowners and resource managers are using to protect their herds and public water sources against the parasite Cryptosporidium parvum; and UC veterinary scientists are part of a large team of experts, including state and federal agencies, determined to combat the endemic bluetongue virus, which can affect the state's exports.

Terrain-Shape Indices for Modeling Soil Moisture Dynamics

This study examined spatial and temporal relationships between measured soil moisture and terrain-based proxies for soil moisture dynamics. Two catenas were intensively sampled reflecting a mosaic of differences in degree of soil development in California's Sierra Foothill Region. A catena containing weakly developed soils (Haploxerepts + Haploxeralfs) formed from granitic parent materials was compared to a catena of well-developed soils (Haploxeralfs and Palexeralfs) formed from metavolcanic parent materials. Soil moisture was monitored at 10-, 30-, and 50-cm depths in 15 profiles in the granitic catena and 100 profiles in the metavolcanic catena. Seven post-rainfall periods during the 2008-2009 water year were selected to compare terrain shape indices and measured soil moisture. No single terrain index (slope, tangential curvature, profile curvature, mean curvature, topographic prominence, terrain characterization index, and compound topographic index [CTI]) consistently described variability in mean water content or dry-down rates, across depth or space. However, within the granitic catena, a combination of CTI and modeled beam radiance consistently accounted for 30 to 70% of the total variance in mean water content at 10 cm, and 10 to 40% at 30- and 50-cm depths. The predictive capacity of digital elevation model (DEM)-derived terrain shape indices for soil moisture dynamics varied widely in time and space, and was influenced by spatial patterns in the degree of soil development. Efforts to describe soil moisture variability are an important attribute of digital soil mapping (DSM). Moreover, soil variability influences soil moisture dynamics, thus synergistic activities are needed to integrate landscape scale variability with digital soil mapping. © Soil Science Society of America, All rights reserved.

Sierra Foothill Research and Extension Center: Research locations

Sierra Foothill Research and Extension Center: Research locations

A quarter century of oak woodland research in the Sierra foothills supports oak restoration

During the last 25 years, a wide variety of oak woodland research has been conducted at the UC Sierra Foothill Research and Extension Center. A substantial portion of this research has focused on developing procedures for artificially regenerating native California oaks. Results indicate that oaks can be successfully established with sufficient care and protection, including thorough weed control and protection from damaging animals. Tree shelters, or grow tubes, have proven particularly useful in getting seedlings to about 6.5 feet (2.0 meters), where they are relatively resistant to cattle browsing. These findings have been disseminated through training sessions and written materials and have been widely adopted by restoration practitioners, improving the overall success rate of oak plantings in California.

California black rails depend on irrigation-fed wetlands in the Sierra Nevada foothills

After California black rails were discovered at the UC Sierra Foothill Research and Extension Center in 1994, an extensive population of this rare, secretive marsh bird was found inhabiting palustrine emergent persistent (PEM1) wetlands throughout the northern Sierra Nevada foothills. We inventoried a variety of PEM1 wetlands to determine which habitats would likely support black rails. Black rails were positively associated with larger PEM1 wetlands that had flowing water, dense vegetation and irrigation water as a primary source; they were negatively associated with fringe wetlands and seasonal water regimes. Recommendations for managing black rail habitat in the northern Sierra foothills include prioritizing the conservation of PEM1 wetlands with permanently or semipermanently flooded water regimes and shallow water zones (less than 1.2 inches), especially those that are greater than 0.25 acres in size; avoiding wetland vegetation removal or overgrazing, especially during the black rail breeding season (approximately March through July); maintaining and improving wetland connectivity; ensuring that impacts to black rails are considered in the environmental review process for development projects; and integrating management guidelines for black rails into existing wetland conservation programs.

Research connects soil hydrology and stream water chemistry in California oak woodlands

The UC Sierra Foothill Research and Extension Center (SFREC) is located in the heart of typical California blue oak and live oak woodlands within metavolcanic terrain of the Sierra Nevada foothills. These types of woodlands often exist at the interface between urban, wild and agricultural lands and are used extensively for livestock grazing, wildlife habitat and surface water supply. Soil surveys for this region and within SFREC depict relatively few soil types compared to areas that support more-intensive agricultural land uses. Despite this inferred homogeneity, our study showed that the biogeochemical and physical properties of soils vary sharply over short distances of less than 10 feet and also experience changes by season and as a result of storm events. An understanding of soil variability in this setting is important to assess rangeland productivity, perennial grass and oak restoration potential, carbon sequestration, stream flow generation and stream water chemistry.

Integrated data-collection system tracks beef cattle from conception to carcass

Data on the performance of individual beef cattle from birth to processing can be used to improve herd management and genetic characteristics such as fertility, weaning weight and tenderness. Likewise, tracing the origins and whereabouts of cattle that may have been exposed to infectious disease agents is necessary to protect the health of the national beef herd. Such information is rarely available, in part because cattle often change ownership during the beef production process. A system developed to support the lifetime tracking of individual cattle in the UC Davis beef herd seamlessly transfers information between the UC Sierra Foothill Research and Extension Center, UC Davis campus feedlot and a commercial beef-cattle processing plant, and provides a repository for performance data collected at all production stages. The system provides real-time data sharing, as well as integrated analysis and management evaluation options, and will be a valuable resource for beef-cattle research. UC livestock farm advisors are now implementing a similar system with cooperating commercial ranches.

Yuba River analysis aims to aid spring-run chinook salmon habitat rehabilitation

Spring-run chinook salmon historically migrated far upstream into Sierra Nevada rivers but are now confined to gravel-limited reaches below large dams ringing the Central Valley. In this study, topographic analysis and photo interpretation reveal the 100-year history of channel conditions in the bedrock canyon on the Yuba River below Englebright Dam, which also abuts the UC Sierra Foothill Research and Extension Center. Historical evidence shows that alluvial bars provided spring-run chinook salmon habitat in the reach prior to gold mining and that the influx of hydraulic mining debris dramatically expanded it. However, when Englebright Dam was completed in 1941, shot rock was left in the canyon and allowed to migrate downstream, where it buried gravel bars. We recommend that shot rock be removed to exhume a pre-existing large gravel bar and that new river gravels be placed in the canyon to create salmon habitat.

Managed grazing and seedling shelters enhance oak regeneration on rangelands

Livestock grazing remains a common practice on California's hardwood rangelands. This can create problems for oak regeneration because grazing has been identified as one of the factors limiting the establishment of certain oak species. Previous research, as well as recent studies at the UC Sierra Foothill Research and Extension Center, suggests that cattle will damage both planted and/or naturally occurring oaks, but damage varies by season with less during the winter when deciduous oaks do not have leaves. Damage is also influenced by the density and distribution of cattle stocking. Oaks taller than 6.5 feet seem relatively resistant to cattle damage in lightly to moderately grazed pastures, but smaller seedlings need protection.

Grazing Effects on Spring Ecosystem Vegetation of California's Hardwood Rangelands

Three watersheds at the University of California's Sierra Foothill Research and Extension Center (SFREC), Marysville, Calif. were selected to study cattle grazing effects on the vegeta - tion surrounding cold-water springs and their downslope creeks. Three spring-creek systems from each of 3 watersheds were ran- domly assigned to grazing treatments (9 total). Treatments were ungrazed, lightly grazed (1,500 kgha -1 residual dry matter), and moderately grazed (1,000 kgha -1 residual dry matter) based on degree of use in upland pastures encircling the spring-creek sys - tems. Total herbaceous cover at springs varied significantly among the 6 years only once (greater in 1994 than all others) covarying with previous year's rainfall. Grazing intensity did not affect total herbaceous cover at springs. A year X grazing treat - ment interaction (P<0.05) was detected for total herbaceous cover at spring-fed creeks. Three years after grazing removal, total herbaceous cover on ungrazed creek plots surpassed cover at moderately grazed and lightly grazed plots. Moderately grazed plot herbaceous cover declined steadily throughout the first 3 years, while lightly grazed cover remained relatively sta - ble. Plant community composition and stability by year and graz - ing treatment were analyzed with TWINSPAN. With few excep- tions, stable plant communities persisted on sites regardless of grazing intensity or cover changes. Total herbaceous cover was sensitive to interannual fluctuations, especially under increased grazing intensities. This attribute renders cover a more useful gauge of ecosystem health than plant composition as the latter may not provide evidence of potentially deleterious grazing X cli - mate interactions until after soil erosion or water table charac- teristics are seriously, perhaps permanently, altered.

Grazing effects on spring ecosystem vegetation of California's hardwood rangelands

Three watersheds at the University of California's Sierra Foothill Research and Extension Center (SFREC), Marysville, Calif. were selected to study cattle grazing effects on the vegetation surrounding cold-water springs and their downslope creeks. Three spring-creek systems from each of 3 watersheds were randomly assigned to grazing treatments (9 total). Treatments were ungrazed, lightly grazed (1,500 kg(.)ha(-1) residual dry matter), and moderately grazed (1,000 kg(.)ha(-1) residual dry matter) based on degree of use in upland pastures encircling the spring-creek systems. Total herbaceous cover at springs varied significantly among the 6 years only once (greater in 1994 than all others covarying with previous year's rainfall. Grazing intensity did not affect total herbaceous cover at springs. A year X grazing treatment interaction (P 0.05) was detected for total herbaceous cover at spring-fed creeks. Three years after grazing removal, total herbaceous cover on ungrazed creek plots surpassed cover at moderately grazed and lightly grazed plots. Moderately grazed plot herbaceous cover declined steadily throughout the first 3 years, while lightly grazed cover remained relatively stable. Plant community composition and stability by year and grazing treatment were analyzed with TWINSPAN. With few exceptions, stable plant communities persisted on sites regardless of grazing intensity or cover changes. Total herbaceous cover was sensitive to interannual fluctuations, especially under increased grazing intensities. This attribute renders cover a more useful gauge of ecosystem health than plant composition as the latter may not provide evidence of potentially deleterious grazing X climate interactions until after soil erosion or water table characteristics are seriously, perhaps permanently, altered.

Habitat Relationships of Amphibians and Reptiles in California Oak Woodlands

We used pitfall traps and time-constrained searches to sample amphibians and reptiles and to describe their habitats in oak woodlands at three areas in California. We captured 766 individuals rep- resenting 15 species during pitfall trapping and 333 animals representing 15 species during the time-con- strained searches. A total of 19 species were sampled. Across all study areas, several positive relationships were found between animal abundance and the cover of specific tree species. At Tejon Ranch, two salaman- ders-Batrachoseps nigriventris and Ensatina eschscholtzii croceater-were associated with canyon live oak (Quercus chrysolepis) and two lizards-Sceloporus occidentalis and Eumeces gilberti-were associated with California black oak (Q. kelloggii). At San Joaquin, B. nigriventris was associated with foothill pine (Pinus sabiniana), as was B. attenuatus at Sierra Foothill. Generally, salamanders were found in live oak woodlands on north-facing slopes at Tejon Ranch, or on north-facing woodlands dominated by foothill pine and interior live oak (Q. wislizenii) at Sierra Foothill and San Joaquin. In contrast, lizards used more xeric and open habitats dominated by California black oak, blue oak (Q. douglasii), and valley oak (Q. lobata). As would be expected for terrestrial and fossorial animals, litter depth, the development of grasses and forbs, and cover by downed woody debris and rocks were important in the habitat models. At Sierra Foothill and San Joaquin, these latter variables, in addition to slope, were of primary importance in the habitat models.

Effects of Cattle Grazing on Blue Oak Seedling Damage and Survival

Cattle grazing has been suggested as a principal cause for poor oak recruitment in California's hardwood rangelands. This study evaluated the effects of stock density and season of grazing on blue oak (Quercus douglasii H. & A.) establishment. In December 1989, seven hundred and twenty blue oak seedlings were planted on 3-m centers in 30 plots in 3 annual grassland pastures at the Sierra Foothill Research and Extension Center east of Marysville, Calif. The treatments consisted of 3 seasons X 3 stock densities plus 1 nongrazed control. During January, April, and July of 1990, steers and heifers (mean = 318 kg) were allowed to graze 1 plot per week at low, medium, and high stock densities (2.5, 7.5, and 15.0 head/ha, respectively). Control plots were used to monitor wildlife browsing. One half of all seedling sites received an application of glyphosate prior to transplanting to eliminate grass competition. Browsing and trampling damage were estimated at the end of each treatment. Total damage (sum of browsing and trampling damage), browsing damage, trampling damage, and survival to April 1991 were significantly different for the 9 season and stock density treatments (P < 0.05). Spring and summer grazing tended to be most damaging and resulted in the lowest survival rates. Within each season total damage increased with stock density but survival did not change significantly. Weed control around oak seedlings had no apparent effect on total damage or survival. There were significant differences in browsing damage between seasons but not between control and grazed plots within seasons (P < 0.05). Survival in ungrazed plots was not significantly different (P < 0.05) from the spring and summer grazed plots. Consequently, the contribution of wildlife to reduced blue oak seedling survival in grazed oak woodlands should not be underestimated.

Survey of Birds and Lizards for Ixodid Ticks (Acari) and Spirochetal Infection in Northern California

A total of 138 birds (24 species) was captured in an oak woodland between December 1988 and June 1989 at the University of California, Sierra Foothill Range Field Station, Yuba County, Calif. Ticks were not found on 71 birds captured between December 1988 and March 1989. Five subadult Ixodes pacificus Cooley & Kohls were removed from 3 of 67 birds caught between April and June 1989. These three birds, an orange-crowned warbler (Vermivora celata (Say], a lazuli bunting (Passerina amoena (Say], and a chipping sparrow (Spizella passerina (Bechstein], represent new host records for I. pacificus in California. Tissues from two ticks and thick blood films prepared from 126 birds tested negative for spirochetes by direct immunofluorescence (DI). A total of 172 larval and 197 nymphal I. pacificus was removed from 15 of 16 western fence lizards (Sceloporus occidentalis Baird & Girard) caught between April and June 1989 in the same location as were birds. Thick blood films prepared from all 16 lizards and tissue smears from 334 of the ticks (143 larvae and 191 nymphs) were DI test-negative for spirochetes. One (1.1%) of 93 adult I. pacificus collected at the bird-lizard capture site in February 1989 was infected with spirochetes that resembled B. burgdorferi.

Sierra Foothill Range Field Station

The Sierra station, near Browns Valley in northern California, will be 30 years old this June:As can be seen from the air, the station's terrain is typical of much of California's foothill rangelands. Wooded, partially wooded, and cleared hills surround the headquarters and slope down to the Timbuctoo Bend of the Yuba River. The following eight reports indicate the variety of subjects covered by the research program at this center. (Cover photo by Charles Raguse)