About Smoke Management
The Jefferson County Smoke Management Program is a cooperative effort of the Jefferson County Seed Growers Association and the Jefferson County Fire Protection District #1. It is committed to a safe, controlled agricultural field burning season that ensures public safety and minimizes, to the greatest degree possible, impacts of smoke on the communities of Central Oregon.
Why We Burn Fields
Fire is a natural part of both forest and grassland ecology. Prairie grasses evolved with fire as a necessary contributor to vitality and renewal. Because of this specific evolution, pre-agricultural societies used controlled burning to regulate both plant and animal life; regenerating grasslands and opening up forests for grassy meadows.
Like others before them, local growers discovered early on that field burning dramatically increased grass vitality; stimulating seed production and lessening need for chemical insect and disease control. Field burning has been a necessary management tool for Central Oregon seed growers since the beginning of the industry in the early 1950s. Despite much research and field tested alternatives, field burning continues to be the safest, most effective management tool that allows Central Oregon seed growers to continue in a viable position in the seed industry.
The creation of the North Unit Irrigation District in the late 1940s, along with a unique climate, helped create the prime seed production industry that Central Oregon is known for today. Clover seed was first produced, and then bluegrass seed became a major industry for the area. Twelve thousand acres planted into bluegrass becomes 10 million dollars’ worth of quality seeds. This translates into a thirty million dollar economic impact to Central Oregon and greater Oregon families and merchants; creating jobs in production, processing, marketing and transportation of this product.
More recently, Central Oregon has become the primary carrot seed producer in the nation, producing 85% of carrot seed planted in the United States. Four thousand acres of carrots becomes a twenty million dollar impact to local revenue.
The early years of seed production were years of uncoordinated field burning. By the 1980s, local growers acknowledged a need for an established program to coordinate and control the burning to minimize smoke impact to area citizens. In 1989 a mandatory smoke management program was created, in coordination with the Rural Fire Protection District and the Jefferson County Commissioners. Growers pay a per-acre burning fee, which pays all the costs of the program – from the temperature flights to the highway flaggers. The program also funds research into alternative crop management practices at the Central Oregon Agricultural Research and Extension Center. A committee of growers, seed industry personnel, fire department administration and community members guide the program with annual input from Jefferson County Commissioners, the Department of Environmental Quality and county seed growers. Throughout the years, the committee has tightened burning restrictions to meet the needs of a growing community.
Summer is the busiest agriculture season. Farmers typically work from dawn to dusk, seven days a week, but growers understand that summer is recreation time for many county residents. Fields are only burned Monday through Friday, and must be finished by 5:00pm (flaming of previously burned fields may be done on Saturdays until 6:00pm). Fields are not burned during special county events such as the Jefferson County Fair, the Air Show of the Cascades, Labor Day and Cycle Oregon. Growers pay for annual air quality monitoring to ensure that their field burning remains withing federal EPA standards. DEQ Air Quality Index
Because of increased traffic on highways 97 and 26, growers voted to enact a ban on burning within 1/8th mile of those highways in 2006. The Jefferson County Seed Growers Association continually refines the program in response to changing community needs. They are committed to operating the best possible smoke management program.
Each day of the Smoke Management Season, the day’s meteorological information is gathered. This includes a temperature flight, conducted around 7:00am, which is sent to the Department of Forestry’s meteorologist. They return a detailed weather forecast for the day, including what the predicted smoke dispersal conditions will be.
A pilot balloon is also released several times each day from the Central Oregon Ag Research and Extension Center and its path is tracked using an instrument known as a theodolyte. This instrument gives precise information that can be used to discover what upper-level wind speeds and directions are present. This information can be used to confirm the ODA forecast.
The burning advisory for the day is then formulated, using an established set of guidelines (Limiting Criteria) to determine if the conditions are favorable. This decision is based on how safely burning can be accomplished and how well the smoke will disperse. If necessary, test fires can be conducted to observe the current conditions and how well they match the forecast.
Growers are notified what the burning advisory is for the day. The burning advisory will give precise information about when fires are to be lit, when they are to be out, and which locations are best suited to the day’s conditions. In addition, any highway burns that are being conducted will be posted and the Jefferson County Sheriff’s office notified, to assist with traffic control as needed.
Once burning has begun, the conditions are monitored and recorded. A daily re-evaluation is made, at approximately 2pm, and if conditions have worsened or if smoke intrusions occur, the burning is halted for the day. If conditions are continuing favorably, more acres are released to burn. Growers are instructed to be ready with rapid-ignition techniques, and can usually begin burning almost immediately upon receiving the “go-ahead”.
Frequently Asked Questions
Q: Why do growers need to burn fields at all?
Grass seed fields are burned for disease and weed control, and for seed promotion. To date, there has been no more effective means to accomplish these ends other than field burning.
Wheat stubble is burned so that the grower may quickly remove the stubble in preparation for planting. Usually, the wheat stubble can be baled as wheat straw. However, if a seed crop is being planted in the field, it is necessary to burn the field so that timely planting of the seed crop can occur.
Q: How long is the season?
There are 9 weeks in burn season. In these 9 weeks, there are usually around 42-45 possible burn days. Growers are not allowed to open field burn on weekends or holidays. If the conditions are not favorable for fire safety or for smoke dispersal, the burning advisory would be posted as a “No Burn Day”. Sometimes a limited number of acres are released on days when conditions are questionable, and limitations are placed on where or when burning can occur. For example, 500 acres may be released to burn, with the condition that all burning be completed by 2pm.
Q: Are there special measures taken when doing a highway burn?
In 2006, growers voted to impose a “no-burn” zone of 1/8th mile alongside the major highways (Hwy 26 and Hwy 97). The large increase in traffic on these highways had created hazardous conditions, despite ODOT certified traffic control. Even with the “no-burn” zone, growers are required to wait for specific wind conditions and ensure that smoke will not drift onto the road.
Burning alongside Hwy 361 (Culver Hwy) is still permitted with ODOT certification, flaggers and Sheriff’s Department traffic control. Because these field burnings must be arranged days in advance (coordination of flaggers, Sheriff’s Dept.) they are sometimes burned on less favorable smoke dispersal days.
Q: Why do we burn fields when there is wildfire smoke in the area?
Because of the relatively short Central Oregon growing season, farmers must precisely coordinate their harvesting and planting for the following seasons. Crops only have limited weeks of summer warmth and irrigation water before the frosts begin and the irrigation water is turned off. The fields must reach a specific point of growth, or they will not survive the winter. Growers can only suspend burning for a few days or risk losing their crops. Meanwhile, the heavily timbered High Desert is certain to burn with wildfires every year. When the air quality monitor registers unsafe levels, growers will restrict burning for a few days (until the stagnant conditions change); but they cannot stop burning for the many weeks (months) that western wildfires continue.
Good Burn Conditions
- Surface winds W, NW or SW (with favorable field location)
- Surface winds 5-15 mph
- Transport winds 5-20 mph, W, NW or SW
- 4000-8000 ft mixing heights
Marginal Burn Conditions
- N or NE surface winds predicted
- Sluggish (< 5 mph) transport winds any direction
- Ventilation index < 25
- Gusty afternoon winds predicted
- Mixing heights near, but not exceeding 3000 ft
No burn Conditions
- 90-20-20 Conditions: (temperature above 90°F, wind over 20 mph, relative humidity less than 20%)
- 0-5 mph transport winds, especially from N or NE
- Weekends (except propane flaming permitted on Saturdays)
Growers register their acres for burning. Season begins late July. Daily detailed weather forecasts and dispersion indexes are obtained via Oregon Department of Agriculture meteorologists. Daily temperature flights gather data to track inversions and aide in determining the time of day for ideal smoke dispersal conditions. Pilot balloons are released daily, and more often as needed, to confirm forecasted wind directions and speeds.
Season continues. The final two weeks of August have been the heaviest burning days in previous seasons. Highway burns are coordinated and scheduled with assistance from Jefferson County Sheriff deputies for traffic control.
Open field burning season ends around the third week in September. After this date, no OPEN field burning is to be conducted until after year end. However, a separate Propane Flaming and Vine Burning Season is extended 4 weeks beyond the end of the regular season, to allow the flaming and burning of the crops harvested later in the season, such as potato vines and carrot vines.
Propane Flaming/Vine burning season ends 4 weeks after the regular season ends. Final reports are prepared for evaluation of the season.
- Open Field Burning: Any agricultural burning not conducted in an authorized burn barrel, excepting areas smaller than one acre and irrigation ditches.
- Propane Flaming: Tractor-drawn propane burner makes consecutive passes across a field, burning along its path.
- Blacklining: Preparatory burn, often conducted early in the day while conditions are cool and damp, around the borders of a field. This is a practice recommended for certain problem fields with adjacent fire hazards.
- Test Fire: A preliminary burn, authorized to assess atmospheric dispersion capacity, and therefore, to determine if open field burning may be advisable during existing weather conditions.
- PiBal (Pilot Balloon): The meterological instrument used to determine upper level wind directions and speeds. A helium-filled weather balloon is released, then tracked using an instrument called a theodolyte. The readings taken from this instrument as it tracks the weather balloon, up to 10,000 ft, can be used to calculate the wind speeds, directions, and the presence of inversions in the upper levels.
- Mixing Height: The lowest height at which the potential temperature exceeds the potential temperature at the surface. In practical terms, it is the approximate height to which a smoke plume will rise, assuming good ignition, dry fuels, and winds less than about 15 mph.
- Ventilation Index: (hml x tws)/100
[hml = height of the mixing layer, tws = transport wind speed]