How do wildfires affect the health and safety of people in agriculture?

Farmers and farmworkers are at a greater risk for exposure to wildfire smoke, ash, and chemical residue due to their work outdoors and long shifts, both during an active fire as well as during cleanup and recovery. Due to the nature of agricultural work, it is difficult for farmers and farmworkers to stop working due to wildfires. Lost workdays and the potential destruction of crops can have an economic effect on both farmers and workers.

Regardless of their proximity to wildfires, agricultural workers can struggle with stress and other mental health issues related to the effects of wildfires. Income, access to healthcare, and immigration concerns increase the vulnerability of the farmworker population.

When a wildfire occurs, what protections and information are employers required to provide to employees?

The newly adopted regulation §5141.1 “Protection from Wildfire Smoke,” which went into effect on July 29, 2019, uses the local air quality index (AQI) for PM2.5 to determine when worker protections are needed.

If employers reasonably anticipate that employees may be exposed to wildfire smoke, they must:

• Monitor the Air Quality Index (AQI) for PM2.5
• Provide training to workers, including how to determine AQI, identify health effects of wildfire smoke exposure, and how to use NIOSH-approved respirators
• Establish worker protection procedures, including a plan to reduce worker exposure to wildfire smoke
• Communicate the above workplace procedures to staff and employees

What is included in the wildfire smoke safety training and resources provided by WCAHS?

WCAHS provides safety resources on wildfire smoke for both employers and employees. An employer checklist outlining the above action items is available in English and Spanish. For training purposes, a double-sided poster and accompanying discussion guide are available in English and Spanish and are useful tools for tailgate trainings and safety reminders in the workplace.

WCAHS is developing an in-person training for agricultural employers and employees that provides a more comprehensive and in-depth review of the health effects of wildfire smoke exposure, worker protection procedures, and more.

Find out more about the Western Center for Agricultural Health and Safety and the Training Program Schedule: https://aghealth.ucdavis.edu/wildfires

The very fact that avocados can be grown in hard to get to places means that the trees are also in areas that are subject to wildfire damage. Recently several hundred acres of avocado burned in the foothills. The fire was fanned by high winds and low humidity.  

Every year there are avocado trees that burn, either through careless attention to early morning fires that pickers build, wildfires or car accidents. A grower needs to be patient and observant to bring the trees back into production.

Although injury to foliage and young growth is visible within a few days of the fire, the full extent of the damage may not be known for several months or possibly the next growing season. In the case of severe injury, die-back may continue to occur for several months after the fire. New growth that occurs after the fire may suddenly collapse the following year when the growth is tested by Santa Ana conditions.

The important rule to follow after a fire is to do nothing - don't prune, don't fertilize and maybe don't water. Or rather, water very carefully. Dry winds may have sucked the water out of the ground and may need to be replenished. The fire may have burned the irrigation lines and need to be replaced.

The need to immediately replace irrigation systems will depend on the time of year, the extent of damage, the soil moisture after the fire, the weather forecast, labor availability and many other considerations. It is not terribly expensive to replace hoses, but if PVC sub mains have burned, it will be a big job and it may not be necessary to jump on their replacement. Check the soil and the tree status before rushing to replace an irrigation system. It is on the list of things to do, but maybe not tomorrow.

In the meantime, if the tree has been defoliated by the fire, it has lost its ability to transpire water. Watering a tree with no leaves will set up those conditions that are conducive to root rot. Until the tree begins to leaf out, watch soil moisture to decide how much water the trees are pulling out of the soil. The emitters should be capped or plugged on some leafless trees. Then as the tree puts on new growth, shallow, infrequent irrigations should start. This may mean replacing the 10 gph microsprinkler with a 1 gph dripper if only a portion of the orchard has been burned and the rest of the trees need their usual amounts and frequency of water.

The avocado has a tremendous ability to come back from fire and frost damage. However, the tree will tell you where it is coming back. It will start pushing growth where the tree is still healthy. It may take 3 to 6 months for this growth to occur.

Delay pruning until the tree clearly shows where it is going to regrow. By waiting, you save the expense of having to return sometime later to remove more wood and also will be able to save the maximum about of tree.

An activity the grower can perform is whitewashing. The defoliated tree can be further damaged by sunburn after it has lost its protective cover of leaves. The upper surface of horizontal limbs and the south sides of exposed trunks are the most affected. The whitewash can delay the appearance of new growth, but it does not affect total growth. There is usually no value in applying the whitewash to small limbs.

There are various commercial whitewashes on the market.  The easiest to prepare is the cheapest white latex paint on the market mixed with water to the extent that it will go through a sprayer.

Avocado trees have a great ability to recover after fire damage. Even trees killed below the bud union will frequently develop into good trees if they are rebudded and given good care. Trees which do not put out vigorous sprouts should be removed. Interplanting avocados would rarely be advisable because of their rapid recovery.

Fire Information:

http://ceventura.ucanr.edu/Agricultural_Threats/Fire_Information/

For another version of fire recovery, go to: https://www.californiaavocadogrowers.com/cultural-management-library/post-fire-grove-recovery

Photos from Kevin Ball, firefighter/farmer

Santa Barbara/Ventura County Farm Service Agency Holds County Committee Election

The People Who Can Help After Disasters

Santa Barbara, Ca, June 18, 2019 – U.S. Department of Agriculture (USDA) Farm Service Agency (FSA) Executive Director Brenda F. Estrada in Santa Barbara/Ventura County reminds farmers and landowners that FSA is holding a 2019 County Office Committee (COC) Election. Producers, including minority, women and new farmers, are encouraged to participate in the 2019 election.

The county committee nomination period began on June 14, 2019. Nomination forms must be postmarked or received in the Santa Barbara/ Ventura County FSA office by close of business on Aug. 1, 2019.

For election purposes, counties are divided into local administrative areas (LAA). Each LAA nominates and elects one producer to serve a three-year term on the FSA county committee.

Each year, an election is held in an LAA where a committee member's three-year term is expiring. For 2019, an election will be held in LAA 3, which includes: The Eastern Area of Santa Barbara County from Santa Maria to the County line.

“Farmers and ranchers in LAA 3 are urged to participate in this year's county committee elections by nominating candidates by the Aug. 1, 2019, deadline,” said Estrada. “County committees are unique to FSA and allow producers to have a voice on federal farm program implementation at the local level.”

To be eligible to serve on an FSA county committee, a person must participate or cooperate in a program administered by FSA, be eligible to vote in a county committee election and reside in the LAA in which the person is a candidate.

Farmers and ranchers may nominate themselves or others. Organizations representing minorities and women also may nominate candidates. To become a candidate, an eligible individual must sign an FSA-669A nomination form. The form and other information about FSA county committee elections is available at fsa.usda.gov/elections. Nomination forms must be postmarked or received in the local USDA service center by close of business on Aug. 1, 2019.

Nationwide, there are approximately 7,800 farmers and ranchers serving on FSA county committees. These individuals make decisions on disaster and conservation programs, emergency programs, commodity price support loan programs and other agricultural issues. Committees consist of three to 11 members who are elected by eligible producers.

Persons with disabilities who require accommodations to attend or participate in this meeting should contact Brenda F. Estrada at 805 434-0396, ext. 2,

Brenda.Estrada@usda.gov

or Federal Relay Service at 1-800-877-8339, by Aug. 1, 2019.

Low-severity wildland fires and prescribed burns have long been presumed by scientists and resource managers to be harmless to soils, but this may not be the case, new research shows.

According to two new studies by a team from the University of California, Merced (UCM) and the Desert Research Institute (DRI), low-severity burns - in which fire moves quickly and soil temperature does not exceed 250oC (482oF) - cause damage to soil structure and organic matter in ways that are not immediately apparent after a fire.

"When you have a high-severity fire, you burn off the organic matter from the soil and the impact is immediate," said Teamrat Ghezzehei, Ph.D., principal investigator of the two studies and Associate Professor of Environmental Soil Physics at UCM. "In a low-severity fire, the organic matter doesn't burn off, and there is no visible destruction right away. But the burning weakens the soil structure, and unless you come back at a later time and carefully look at the soil, you wouldn't notice the damage."

DRI researcher Markus Berli, Ph.D., Associate Research Professor of Environmental Science, became interested in studying this phenomenon while visiting a burned area near Ely, Nev. in 2009, where he made the unexpected observation that a prescribed, low-severity fire had resulted in soil structure damage in the burned area. He and several colleagues from DRI conducted a follow-up study on another controlled burn in the area, and found that soil structure that appeared to be fine immediately after a fire but deteriorated over the weeks and months that followed. Berli then teamed up with Ghezzehei and a team from UCM that included graduate student Mathew Jian, and Associate Professor Asmeret Asefaw Berhe, Ph.D., to further investigate.

Soil consists of large and small mineral particles (gravel, sand, silt, and clay) which are bound together by organic matter, water and other materials to form aggregates. When soil aggregates are exposed to severe fires, the organic matter burns, altering the physical structure of the soil and increasing the risk of erosion in burned areas. In low-severity burn areas where organic matter doesn't experience significant losses, the team wondered if the soil structure was being degraded by another process, such as by the boiling of water held within soil aggregates?

In a study published in AGU Geophysical Research Letters in May 2018, the UCM-DRI team investigated this question, using soil samples from an unburned forest area in Mariposa County, Calif. and from unburned shrubland in Clark County, Nev. to analyze the impacts of low-severity fires on soil structure. They heated soil aggregates to temperatures that simulated the conditions of a low-severity fire (175oC/347oF) over a 15-minute period, then looked for changes in the soil's internal pore pressure and tensile strength (the force required to pull the aggregate apart).

During the experiment, they observed that pore pressure within the soil aggregates rose to a peak as water boiled and vaporized, then dropped as the bonds in the soil aggregates broke and vapor escaped. Tensile strength measurements showed that the wetter soil aggregates had been weakened more than drier soil samples during this process.

"Our results show that the heat produced by low-severity fires is actually enough to do damage to soil structure, and that the damage is worse if the soils are wet," Berli explained. "This is important information for resource managers because it implies that prescribed burns and other fires that occur during wetter times of year may be more harmful to soils than fires that occur during dry times."Next, the research team wondered what the impact of this structural degradation was on the organic matter that the soil structure normally protects. Soil organic matter consists primarily of microbes and decomposing plant tissue, and contributes to the overall stability and water-holding capacity of soils.

In a second study that was published in Frontiers in Environmental Science in late July, the UCM-DRI research team conducted simulated burn experiments to weaken the structure of the soil aggregates, and tested the soils for changes in quality and quantity of several types of organic matter over a 70-day period.

They found that heating of soils led to the release of organic carbon into the atmosphere as CO2 during the weeks and months after the fire, and again found that the highest levels of degradation occurred in soils that were moist. This loss of organic carbon is important for several reasons, Ghezzehei explained.

"The loss of organic matter from soil to the atmosphere directly contributes to climate change, because that carbon is released as CO2," Ghezzehei said. "Organic matter that is lost due to fires is also the most important reserve of nutrients for soil micro-organisms, and it is the glue that holds soil aggregates together. Once you lose the structure, there are a lot of other things that happen. For example, infiltration becomes slower, you get more runoff, you have erosion."

Although the research team's findings showed several detrimental effects of fire on soils, low-severity wildfires and prescribed burns are known to benefit ecosystems in other ways -- recycling nutrients back into the soil and getting rid of overgrown vegetation, for example. It is not yet clear whether the negative impacts on soil associated with these low-severity fires outweigh the positives, Berli says, but the team hopes that their research results will help to inform land managers as they manage wildfires and plan prescribed burns.

"There is very little fuel in arid and semi-arid areas, and thus fires tend to be short lived and relatively low in peak temperature," Ghezzehei said. "In contrast to the hot fires and that burn for days and weeks that we see in the news, these seem to be benign and we usually treat them as such. Our work shows that low-severity fires are not as harmless as they may appear."

The study, "Soil Structural Degradation During Low?Severity Burns," was published on May 31, 2018 in the journal AGU Geophysical Research Letters and is available here: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL078053.

The study, "Vulnerability of Physically Protected Soil Organic Carbon to Loss Under Low Severity Fires," was published July 19, 2018 in the journal Frontiers in Environmental Science, and is available here: https://www.frontiersin.org/articles/10.3389/fenvs.2018.00066/full.

https://www.eurekalert.org/pub_releases/2018-09/dri-lwi091018.php