Open Space Advisory Board Agenda and Packet 2023 08 09

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grow during cool seasons and therefore reduce fuel at that time, so shortgrass prairie restoration on open space is a useful strategy for fire mitigation. Prairie dog maintenance: Prairie dogs dramatically reduce the amount of fuel on open space land, sometimes reducing the grasses to bare earth, and thus are very useful for fire mitigation. She listed several potential disadvantages of prairie dogs on open space, including that total removal of grass can reduce the visual appeal of the prairie and allow non -natives opportunities for establishment. Broadscale mechanical mowing: Mowing entire open space properties was not recommended. She noted that if the clippings from the mowing are not removed, then they could exacerbate ember production during a high -wind event. However, in a lower -wind event, they might not be harmful. There are a lot of concerns about broadscale mowing, such as reducing wildlife habitat and directly killing wildlife. The consultants concluded that possible advantages of broadscale mowing are outweighed by the unfavorable tradeoffs for the land. Mowing specific fuel breaks: While broadscale mechanical mowing was not recommended, the targeted creation of mowed fuel breaks was recommended. fuel breaks can reduce grass height and potential flame lengths, while giving control lines and access points to firefighters during fires. Meg pointed out that fuel break mowing could potentially give citizens a false sense of security about their wildfire risk, especially as they are less useful during high -wind events. It is unclear how wide a fuel break needs to be in order to be effective. She presented some research where scientists have tried to model the success of different fuel break widths under varying conditions, but the research is ambiguous and hard to apply to the scenario of the actual Marshall Fire. Meg concluded that 8-12 foot fuel breaks would probably be helpful for many fires, but they wouldn't have helped much during the very dry, very windy conditions of the Marshall Fire, where even a maximalist 30 foot fuel break would not have helped. To illustrate this assertion, she shared that even the trees of the Target parking lot burned on the day of the Marshall Fire, despite being surrounded by ideal firebreaks of concrete and asphalt. Charles asked whether the city trails themselves can act as fuel breaks, as they are hard - surface, 8-10 feet wide, and their margins get mowed. Meg said that trails are often on the interior of open spaces. Fuel breaks need to be placed closer to the things they are trying to protect, like the houses around the perimeter of open space properties. Structure hardening: While structure hardening doesn't much apply to open space, there aren't many cons to structure hardening. Meg noted that the Rec Center is a great example of a hardened structure, but there are city parks where mulch might need to be reconsidered as a playground surface. Mulch can smolder and produce embers. Irrigation and spot watering: This is a strategy that was recommended by citizens at the public meeting, but Meg and her team determined that it is not practical for open space and non - irrigated parks. In general irrigation is only used on open space temporarily, where specific plants are being established. She pointed out that irrigation can improve the moisture content in the field, but on hot, dry days, it evaporates too quickly to be useful. Watering can also stimulate plant growth, actually causing an increase in fuel load for fires. Meg touched on several other recommendations, such as incentive programs for private fence replacement and vegetation removal, fire prevention education campaigns, public surveys to determine public opinions on management tradeoffs (to ensure policy is not determined solely