Posts Tagged: oak woodlands
Delight in Napa Valley's Plant Communities
One of the things I love about the Napa Valley is its sense of community. For most of us,...
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Partnership brings $2.6 million to North Coast to restore oak woodlands
The loss of oak woodlands in California's North Coast is a critical conservation concern because it is associated with losses of biodiversity and wildlife habitat, range values, cultural resources, and other oak-dependent ecosystem services. In the absence of natural disturbances like fire, conifers can outcompete deciduous oaks and eventually the oaks die. In recent years, the effects of conifer encroachment on oaks have become a focal point for UC Agriculture and Natural Resources, which has conducted important research on oak woodland conservation in Humboldt and Mendocino counties.
“UC ANR research has shown that conifer encroachment is threatening oak woodlands throughout the North Coast. This project is really exciting because it will give landowners the resources they need to restore their oak stands — resources that haven't been there in the past,” said Lenya Quinn-Davidson, UC ANR Cooperative Extension staff research associate, who led development of the project proposal.
Oak woodland restoration requires removing conifers from oak stands with prescribed fire or by cutting down the conifer trees.
“The North Coast Oak Woodland Conservation Project will provide technical guidance and resources for landowners who wish to restore or conserve their oak woodlands, and foster a strong alliance of organizations and agencies who can continue oak woodland conservation efforts into the future,” said Quinn-Davidson, who is based in Eureka.
For more information about the project or funds for oak conservation activities on private lands, contact Quinn-Davidson at lquinndavidson@ucanr.edu and (707) 445-7351.
The North Coast Oak Woodland Conservation Project was one of six projects in California selected for Regional Conservation Partnership Program funding. The funded projects focus on a range of issues, including bird habitat, climate change and forest health. The program, which is funding 84 projects totaling $220 million nationwide, is highly competitive, requiring strong partnerships that address critical conservation issues.
"We are excited and energized by these new projects that bring together a diverse mix of partners to improve California's ecosystems and landscape," said Carlos Suarez, Natural Resources Conservation Service state conservationist. "It is very powerful to be able to engage in partnerships that embrace both agricultural and environmental interests and perspectives—and find collaborative ways of making progress on critical issues."
Partners in the North Coast Oak Woodland Conservation Project include University of California Cooperative Extension, CAL FIRE, the Watershed Research and Training Center, the North Coast Regional Land Trust, the U.S. Fish and Wildlife Service, the Mattole Restoration Council, Yager/Van Duzen Environmental Stewards, and the Mendocino County Resource Conservation District.
UC IPM Releases Management Guidelines for Goldspotted Oak Borer
First identified in California in 2004, the goldspotted oak borer (GSOB), Agrilus auroguttatus, has killed more than 24,000 oak trees in San Diego County since its arrival, probably in the late 1990s. In 2012, it was detected in Riverside County and it is expected to spread northward in the state.
The most seriously damaged oaks are those in the red oak group including coast live oak, Quercus agrifolia, and black oak, Q. kelloggi. It also infests canyon live oak, Q. chrysolepis but has not been found to kill the other native oak species in the area, the Englemann oak, Q. englemanni. So far losses have been most serious in parks and forested areas, but landscape trees are also being killed.
A new Pest Note from the UC IPM program outlines management guidelines for this serious pest. Flatheaded borers such as GSOB are difficult to manage and seriously infested trees cannot be saved. The primary way GSOB spreads into new areas is through the movement of infested wood and the authors recommend leaving infested wood on site for 2 years. If wood is to be moved, the Pest Note provides guidelines for treating it through containment, grinding, and debarking. Guidelines for replanting infested areas, less susceptible oak species, biological control, insecticide applications and developing GSOB management plans are also described.
Many other borers attack oaks but do not kill trees. GSOB infested trees can be distinguished by the characteristic D-shaped emergence holes it leaves behind. A special feature of the Pest Note is a table illustrating the emergence holes of borer species on southern California oaks. Many photos are also included.
The information in this Pest Note: Goldspotted Oak Borer is based primarily on research studies by the authors: Mary Louise Flint (UCIPM and Entomology/UC Davis), Tom Coleman and Steve Seybold (USDA/US Forest Service), and Mike Jones (Entomology/UC Davis). Find it at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74163.html
Long-term study: Conservation tillage saves oil, soil and toil in cotton
Conservation tillage seeks to reduce the number of times that tractors cross the field, in order to protect the soil from erosion and compaction, and save time, fuel and labor costs. Cotton crops are planted directly into stubble from the previous crop in the rotation.
In the study, conducted from 2000 to 2011 at the UC West Side Research and Extension Center in Five Points (southwest of Fresno), the number of tractor passes for a cotton-tomato rotation grown with a cover crop was reduced from 20 in the standard treatment to 13 with conservation tillage.
By the final years of the in the San Joaquin Valley study, cotton lint yields were statistically equivalent and even higher (in 2011) than with standard cultivation methods.
“The UC studies have consistently shown that conservation tillage can yield as well as standard tillage in a cotton-tomato rotation,” lead author Jeffrey P. Mitchell, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis, and co-authors wrote in California Agriculture journal.
Their study, “Conservation tillage systems for cotton advance in the San Joaquin Valley,” as well as the entire July-September 2012 issue of California Agriculture journal, can be viewed and downloaded online at: http://californiaagriculture.ucanr.edu.
Mitchell is a founder of Conservation Agriculture Systems Innovation (CASI), a diverse group of more than 1,800 farmers, industry representatives, UC and other university faculty, and members of the Natural Resources Conservation Service and other public agencies (http://ucanr.edu/CASI). CASI defines conservation tillage as a suite of cultivation practices — including no-tillage, minimum tillage, ridge tillage and strip tillage — that reduce the volume of soil disturbed and preserve crop residues in the field. Conservation tillage is common in other regions of the United States and parts of the world and is beginning to gain acceptance in California agriculture.
Technological upgrades to tillage implements have been critical to the advancement of conservation tillage systems. These include equipment that can target operations to just the plant row rather than the whole field as well as accomplish several operations at the same time.
Fuel use was reduced by 12 gallons and labor by 2 hours per acre in the conservation tillage plots. This amounted to savings of about $70 per acre in 2011 dollars.
Mitchell noted that more research is needed on the adequate development of cotton stands and the prevention of soil compaction under different conditions, but that the benefits of conservation tillage are becoming increasingly obvious. “Provided that yield performance or more importantly bottom-line profitability can be maintained and the risks associated with adopting a new tillage system are deemed reasonable, conservation tillage systems may become increasingly attractive to producers and more common in San Joaquin Valley cotton-growing areas.”
Also in the July-September 2012 issue of California Agriculture:
Agricultural burning and air quality: Southern California farmers in Imperial County regularly burn crop residues of bermudagrass in the winter and wheat stubble in the summer. A study of ambient air quality adjacent to and downwind of agricultural burning sites in the desert county found that particulate matter levels (PM2.5) were 23% higher on burn days than on no-burn days at four locations. Researchers from the California Department of Public Health also assessed community educational needs regarding agricultural burning and developed fact sheets in English and Spanish targeting the general public, schools and farmers.
The value of privately owned oak woodlands: More than 80 percent of California’s 5 million oak woodland acres are privately owned. In a survey, researchers from Spain and UC Berkeley asked private owners of California oak woodlands to place a monetary value on amenities from their land such as recreation, scenic beauty or a rural lifestyle. The technique, called “contingent valuation,” found that landowners would be willing to pay $54 per acre annually for private amenities from their land and that their willingness to pay per acre decreased as their property size increased.
Microchips for woody plants: Radio-frequency identification (RFID) tags are widely used to track books in libraries, products during manufacturing, cattle from rangeland to the slaughterhouse, inventory in retail, runners in road races and much more. These tiny microchips (often the size of a grain of rice) are now being placed in woody plants such as grapevines and orchards to monitor crop diseases, track irrigation and pesticide applications, and help prevent the theft of valuable plants. In this review, Italian researchers discuss the emerging uses of RFID technology in agriculture.
Rainfall simulators to measure erosion: In their efforts to keep Lake Tahoe clear, researchers have been studying the movement of sediments into the lake using rainfall simulators. These fairly simple machines are placed on a slope; “rain” is created over a small frame, which allows sediment in the runoff to be collected and measured. However, the lack of standardization in erosion studies using rainfall simulators may be hampering progress. Mark Grismer, professor in the Department of Land, Air and Water Resources at UC Davis, makes the case for standardized field methodologies and data analysis.
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California Agriculture is the University of California’s peer-reviewed journal of research in agricultural, natural and human resources. For a free subscription, go to: http://californiaagriculture.ucanr.edu, or write to calag@ucanr.edu.
WRITERS/EDITORS: To request a hard copy of the journal, e-mail jlbyron@ucanr.edu.
Droughts: A Challenge to Ranching in Oak Woodlands
Most of the oak woodlands in California are privately owned. The major use of Oak Woodlands is for grazing, primarily for beef cattle. The ranching industry plays an important role in maintaining a sustainable, culturally meaningful, and ecologically rich landscape (Huntsinger and Hopkinson, 1996) in our oak woodlands. Of the many challenges facing ranchers, droughts can be severe.
The great drought of 1862–1865 wreaked havoc on the state and the cattle industry (Burcham, 1957). Since that time we have had severe droughts about 8 times (George et. al. 2010). Even with less severe droughts, cattlemen have a stressful time dealing with changes in forage production. With less forage production, cattlemen either have to reduce herd size, move cattle to other states or locations, or provide extra feed at a great expense. If cattle are sold, it may take several years to build the herd back.
Not all droughts are equal. Droughts tend to be more common in the rain shadow along the Coast Range adjacent to the west edge of the San Joaquin Valley (George et. al. 2010). Even though drought conditions create havoc with management of ranches, ranchers also have to deal with wetter than normal years. There is no such thing as an average year, which makes management decisions very difficult. Forage production and quality can vary greatly from year to year, and is strongly influenced by the timing and amount of rainfall (George et. al. 2001). For example, forage production in San Luis Obispo County over the last 11 years has varied by as much as 4000 lbs/ac (Figure 1). Rainfall amount and timing played a significant role in this variation, which varied by 18 inches of annual precipitation.
Figure 1: Peak Forage Production in San Luis Obispo County from 2001 – 2011.
An average of 12 sites across the county.
It is just a fact of life that rainfall amount and timing varies. For example, the lowest rainfall recorded in downtown Paso Robles was 4.8 inches in 1898 (Figure 2). The highest recorded was 31.3 inches in 1969, the year of the big flood. It is important to notice that 6 out 10 years are below average (Figure 2). This means that the four years that are above average are usually wet years, which often produces extra forage. For more practical purposes, the years that are below the average determine what and how much forage can be produced on a ranch, which determines the number of cattle that can be grazed on a sustainable basis. It is very important to the ecological health of the oak woodlands / grasslands to maintain proper stocking rates to achieve the desired grazing level. Maintaining the proper amount of residual dry matter (RDM) has become the standard to determine grazing use on oak woodlands and annual grasslands. Properly managed RDM provides protection from soil erosion and nutrient losses, and also plays an important role determining the following year’s production and composition of species (Bartolome et. al. 2006). To accomplish this requires constant change in management by ranchers. I applaud those ranchers who work so hard to accomplish this.
Figure 2: Rainfall records at the down town Paso Robles. Data is based on water
year July 1 – June 30. Average precipitation is 15 in/yr.
Below are images taken of the peak forage production for San Luis Obispo County:
Spring 2006 normal, wet conditions
Soda Lake Site Cambria Site
Spring 2007 drought conditions
Soda Lake Site Cambria Site
References
Burcham, L.T. 1957. California range land: An historico-ecological study of the range resource of California. Division of Forestry, Department of Natural Resources, State of California, Sacramento, California, USA.
Bartolome, J.W., W.E. Frost, N.K. McDougald, and M. Connor. 2006. California guidelines for residual dry matter (RDM) management on the coastal and foothill annual rangelands. Oakland, CA USA: Division of Agriculture and Natural Resources, University of California, Publication 8092.
Huntsinger, L. and P. Hopkinson. 1996. Viewpoint: Sustaining rangeland landscapes: a social and ecological process. Journal of Range Management 49(2):167-173.
George, M.R., R.E. Larsen, N.M. McDougald, C.E. Vaughn, D.K. Flavell, D.M. Dudley, W.E. Frost, K.D. Striby, and L.C. Forero. 2010. Determining Drought on California’s Mediterranean-Type Rangelands: The Noninsured Crop Disaster Assistance Program. Rangelands 32(3):16-20.