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There are many factors at play when determining whether a prescribed burn moves forward or not.  A team of collaborators is in a state of constant assessment of temperature, humidity, site preparedness, wind speed, availability of personnel and equipment, and much more. Because of the difficulty in aligning all these factors on a certain date, it is common for burns to be canceled, even at the last minute. This was the case when we called off a prescribed burn at Van Hoosear Wildflower Preserve last week. Our burn boss, Phil Dye of Prometheus Fire Consulting, made the decision that not all conditions were aligned enough to conduct a safe burn. Safety overrides all other objectives. We are glad to report that our systems and team worked well together to make the right call to ensure the safety of our community, the land, and our team. 

Prescribed burns differ greatly from a wildfire. Prescribed fires burn at a low temperature and have constant management by many trained onsite personnel, keeping the fire controlled and within the bounds of carefully defined perimeters. The fire is managed to burn at a temperature that produces a desired ecological effect. There are firefighters and fire trucks, including water tanker trucks, standing by. With a high ratio of skilled staff and equipment to fire size, and with long term planning and preparation, there is a very low risk associated with prescribed burns held at the Preserve. Anything that hints at potential inability to control a burn is cause for cancellation of the event. 

Burns at Van Hoosear Wildflower Preserve have been conducted in the early summer (May to early June) to reduce the presence of medusahead, a nonnative annual grass that decays very slowly, and that over years creates a thick thatch of dead stems that block light from reaching the ground. When medusahead is permitted to flourish, seeds of other plants, like those of annual native species that the preserve was created to help protect, are less likely to germinate. Our 2020 and 2021 burns, which occurred in different, medusahead-infested portions of the Preserve, succeeded in virtually eliminating medusahead. Our goal this year was to burn a third section of the Preserve to control medusahead. 

Stewardship of this special part of Sonoma Valley helps maintain one of the few meadows in our area with high native biodiversity. Once medusahead is under control, we plan to switch to burning in late summer, early fall, and only every 3 to 5 years, because the later timing is more beneficial for overall grassland biodiversity. Later burns stimulate perennial grasses and flowers, including bulbs like lilies and irises, most of which are native. Later burns also occur after the flowering season is over, so plants that mature later have a chance to reproduce. These burns will, of course, be carried out with the same exacting oversight to assure safety and effectiveness. 

Prescribed burns at the Preserve, like other management activities there, are funded primarily by an endowment set up when the Preserve was protected by a conservation easement. The easement is held and enforced by Sonoma County Ag + Open Space, an agency set up by the voters of Sonoma County and funded by a ¼ cent sales tax. The endowment is administered by Marin Community Foundation. Funds are spent in accordance with a management plan, written by SEC and approved by Sonoma County Ag + Open Space and the Preserve’s landowners.

Many thanks to the landowners of the Van Hoosear Wildflower Preserve, who voluntarily protected this beautiful land from development in perpetuity, to Sonoma County Ag + Open Space and California Wildlife Conservation Board for purchasing its development rights, and to the taxpayers of Sonoma County and the State for funding these agencies.

The Van Hoosear Wildflower Preserve is on unceded territory of Miwok and Graton Rancheria people. 

The 2022 Van Hoosear Wildflower Preserve prescribed burn is organized by Sonoma Ecology Center and Sonoma Valley Fire District, with support from ACR’s Fire Forward team and the volunteer members of the Good Fire Alliance, led by burn boss Phil Dye of Prometheus Fire Consulting.