College of Natural Resources, UC Berkeley

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August 24, 2005

Mexican woods offer a look at California forests’ past


by UC Division of Agriculture & Natural Resources

A largely unmanaged forest in Mexico holds lessons for improving the health of California wildlands, according to UC Berkeley fire science professor Scott Stephens.

His twice yearly research expeditions to the unspoiled Sierra de San Pedro Martir have convinced him that the forest management plans in California should be revised to improve the ecosystem’s resilience to insects, diseases, drought and catastrophic fires.

For seven years, Stephens has studied the Jeffrey Pine-mixed conifer forests in the mountainous national park of Baja California, named after the Christian martyr St. Peter. The mountain range is connected to the Laguna and San Jacinto Mountains of southwest California. The flora and fauna are similar to Southern California and eastern Sierra Nevada forests. The greatest difference is the time of the forests’ fire seasons. The majority of fires occur in summer in the Mexican forests, but fires are more common in California forests in the late summer and fall.

“When you are over there, with all the familiar shrubs and soils and trees, sometimes you have to remind yourself you’re in Mexico,” Stephens said.

A large portion of the 100,000-acre Mexican forest has never been harvested and has survived through centuries of natural fire cycles, making it a living example of what many California forests would be without the exploitive logging practices of earlier generations, fragmentation by development and disruption of natural fire cycles.

Fires burned naturally in Sierra San Pedro Martir

Until 1970, there was no fire suppression at all in the Sierra de San Pedro Martir. Today, only eight people are assigned to put out blazes by going in when smoke is spotted and cutting a line around the fire. In contrast, most California forest fires are managed aggressively with armies of firefighters, sophisticated equipment, helicopters and air tankers.

Vacation homes, developed camp grounds, lavish lodges, museums and shopping centers are not to be found in Mexico’s Martir. In California, many mountain areas have become populous tourist destinations. Twelve thousand people live in the vicinity of Big Bear Lake, where a local Web site,, claims there are more Mexican restaurants per capita than in the average Baja peninsula city. The population at Mammoth Lakes, on the eastern side of the Sierra Nevada Mountain Range, is nearly 8,000 year round. The average cabin in Lake Arrowhead, known locally as the Alps of Southern California, costs more than $200,000.

Another influence on current California forest ecosystem is historical timber harvesting practices. Some 125 years ago, California and Nevada pioneers began logging the eastern Sierra Nevada and the San Jacinto, San Bernardino and Laguna mountains for mining and development.

“In the late 19th century, most of the trees in the eastern Sierra Nevada were used to support silver mining,” Stephens said. “The logging that took place before early Californians understood sustainable timber harvest practices created huge disturbances in the forest ecosystems that still affect those forests today.”

Differences are profound

The differences Stephens and his staff have seen in the never-touched and frequently burned Mexican forests compared to California’s fire-suppressed and highly developed forests, Stephens said, are striking.

For example, in the early 2000s, following a few years of drought, the Southern California mountain landscape was dominated by dead trees, which had succumbed to native bark beetle attacks. The Mexican mountains experienced the same drought, but many more trees were able to survive the bark beetle onslaught. Further, in 2003, a 10,000-acre wildfire took place in the Mexican range.

“We’ve been working in that wildfire area,” Stephens said. “Even though the trees were incredibly stressed by drought, less than 4 percent of the over story trees are dying. At the end of the drought in California, even without the fire, many more trees were dead. Martir has resiliency that we don’t see anywhere in California.”

Stephens attributes the resiliency to the Mexican forest’s diversity. When Stephens and his staff surveyed the forest, they were able to calculate average numbers of dead snags, old-growth trees, saplings and downed wood on the forest floor over large areas, but individual plots reflect this average only 10 percent to 15 percent of the time.

“That means in 85 percent of the area, there is tremendous variation in the forest makeup,” Stephens said. “But what we’re doing in the United States is actively managing forests for average conditions and what we’re getting is a giant carpet of trees. When all the forest areas are the same, fires, disease and insects can more easily move through entire stands.”

Diversity breeds resilience

The effects of relatively frequent, lower intensity fire found in the Martir are variable and patchy forests. When later threats encounter patches and spaces, the forests have a greater ability to survive.

Based on his research in Mexico, Stephens said he believes the approach taken in the United States in forest management must be changed. He suggests greater forest diversity can be achieved by giving greater latitude to “on the ground” forest managers, allowing them to be creative rather than strictly adhering to per-acre management plans.

“They can go in and try some things to break up the homogeneity,” Stephens said.

Stephens’ forest studies are funded in large part by the UC Agricultural Experiment Station, an organization of researchers on the Riverside, Davis and Berkeley campuses affiliated with the UC Division of Agriculture and Natural Resources. Stephens’ next trip to the forests of Sierra de San Pedro Martir is scheduled for October.

August 22, 2005

Cal Still No. 1 National Public University

by Michelle Maitre

Magazine ranks Berkeley top public university, 20th among all colleges in country

UNIVERSITY OF CALIFORNIA, BERKELEY has again ranked as the nation's best public university in U.S. News and World Report's annual list of top colleges.

The magazine's "America's Best Colleges" rankings, released today, are based on a formula that includes graduation and retention rates, faculty resources, peer review and other factors. UC Berkeley has held the top public spot for several years, occasionally tying with the University of Virginia.

While UC Berkeley is the top-rated public university, the campus ties with Emory University in Georgia for 20th overall on a list that compares both private and public universities....

The rankings will be published in Monday's edition of the magazine. The list will be available online today at U.S.News....

Full Story at Inside Bay Area.

August 1, 2005

UC gives tips for coping with heat stress

by Pam Kan-Rice
The heat-related death of a man harvesting peppers in Kern County last month is a tragic reminder of the dangers of heat stress.

To help reduce dangers of becoming overheated, a University of California Cooperative Extension specialist has produced a heat-stress information card for farmworkers that explains in English and Spanish how heat-related illnesses develop and how to avoid them.

Download a fold-up heat stress information card in English and Spanish (PDF)

More references about heat stress are available here.

Although the advice is directed at farmworkers, it is useful to anyone who works in the heat.

UC Berkeley-based agricultural personnel management specialist Howard Rosenberg warns that excess heat can impair the body even before a person feels ill. Symptoms of heat stress may include general discomfort, loss of coordination and stamina, weakness, poor concentration, irritability, muscle pain and cramping, fatigue, blurry vision, headache, dizziness, nausea, confusion, and unconsciousness (see "Heat illness symptoms and first aid" sidebar).

Although some of the heat that people have to deal with at work comes from the sun and ambient air, most heat is generated by their own bodies, Rosenberg says. "At rest the body produces little heat, but at work it demands more energy and faster metabolism, which greatly increases internal heat production," he explains.

To cool itself, the body first increases blood flow toward the body surface. This reduces the flow available to carry oxygen and nutrients to the muscles, brain and other internal organs, which in turn impairs strength, diminishes alertness and accelerates fatigue.

"When this mechanism doesn't release heat fast enough, sweat glands kick in," says Rosenberg. "They draw water from the bloodstream to form sweat that carries heat across outer layers of the skin and then evaporates." The loss of water through sweating impairs the body's ability to cool itself later, and the loss of electrolytes in sweat can cause muscle cramps.

The longer sweating goes on, the less blood volume remains and the greater the health risk. Rosenberg gives this cautionary example: a 150-pound man working moderately in warm weather would lose about 3/4 quart of water -- or 1 percent of his body weight -- per hour. At that rate, without replacing the lost fluid, he would likely experience diminished energy and endurance after three hours, serious fatigue and nausea after six hours, and loss of consciousness after eight hours (see "How heat affects the body" sidebar).

He recommends drinking water even before being prompted by thirst because thirst is a late signal of a water deficit. "Chugging to quench an intense thirst is like pouring water on a wilted plant," Rosenberg says.

For farm operations, Rosenberg recommends that managers and foremen try to keep drinking water containers as close as possible to centers of activity. If the water is too far away, such as at the end of a long row, workers may not want to take time away from their tasks or exert the extra effort to get to it.

Rosenberg also recommends bringing "a little heat-stress physiology 101 to the field" -- helping workers understand the causes of heat stress, their own bodies' heat release mechanisms, and the critical importance of replenishing the fluid they lose as sweat. "We hope the new card enables more growers to effectively deliver information that their employees need to know."

If workers begin experiencing heat stress symptoms, Rosenberg advises having them rest, preferably in a cooler area, and drink plenty of water or electrolyte fluids. In case of heat stroke, immediate medical attention should be sought.

AB 805, a bill pending in the California Legislature, would add specific heat-illness prevention and response requirements to employers' existing obligations for workplace safety. This month, after more than three inactive years, a Cal/OSHA advisory committee resumed its consideration of a new industrial regulation that would help prevent heat illness and injury in the workplace.

The card is being produced in cooperation with California Farm Bureau Federation, California Grape and Tree Fruit League, and California Association of Winegrape Growers, with additional USDA support through its Western Center for Risk Management Education.

To order free copies of the bilingual heat-stress education cards for farmworkers, contact Elisa Noble at or (916) 561-5598.

Student Resource Center gets new computers


The College of Natural Resources’ Student Resource Center located in 260 Mulford recently acquired ten new computers, replacing older computers that did not meet University security standards.

The new computers not only meet security standards, but also provide faster and more powerful computing.

The computers were purchased with funds from the Berkeley Fund for Natural Resources, which is generously supported by hundreds of alumni and friends of the College.

Over the years the Student Resource Center has grown as an education portal for CNR students. With the new computers, students have improved tools to help with homework and group projects.


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Mexican woods offer a look at California forests’ past
Cal Still No. 1 National Public University
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