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Learning from Sonoma County: How Vegetation Maps can Prevent Fires in San Mateo County

image_firedamagema_20190613-192240_1 Fire Damage Map of Woody Vegetation

We were delighted to have our guests from Sonoma County come down for our Fire Safe San Mateo County workshop Wednesday, June 12th, 2019. In anticipation for a collaborative, multi-agency County-wide vegetation mapping project "San Mateo County Vegetation Map and Landscape Database Project", guests spoke upon the current progress of the mapping project within San Mateo County and applicative uses for the maps, focusing on fuel load and fire modeling from Sonoma County's mapping project. We've summarized our guest's presentations below. 

The ultimate goals of the San Mateo vegetation mapping project are large and ongoing. So far, the project has been able to produce high resolution imagery and LiDar data, a method of remote sensing that creates a 3-D representation of the landscape. From these original data sets, and with the help from an army of botanists, the project aims to produce fine scale vegetation type maps, fire fuels mapping, relative forest stand cover, impervious surfaces layer mapping, hydrologic system mapping and topographic modeling and contours. With enough funding, more maps can created from the original data. Altogether, the applicative uses of the data produced will be limited to the imagination. Ultimate completion of the project is slated for January 2022. The final maps (available in GIS format) will be available at San Mateo County's GIS webportal

In Sonoma County, a similar mapping project was completed in 2017. The final product is provided not only as downloadable packages, but also through a user friendly mapping webportaland "Story Map". These easy to use maps bring the wealth of information this project brings to the greater public, including local government, State government, academia, communities, Resource Conservation Districts, non-profits and commercial entities. This data has been used for a myriad of reasons, spanning wetland conservation, agricultural protection, old-growth redwood research, carbon sequestration research, floodplain and creek restoration and planning along with so much more. Check out their website at sonomavegmap.org

Following the 2017 Sonoma Complex fires which started October 8th, 2017, Sonoma suffered devastating impacts from the combined destruction from the Pocket, Tubbs and Nuns Fire. In the aftermath, there were many questions as to why the fires spread the way they did and with such destructive force. Fires are not new to Sonoma County, there have been multiple historical fires, predominantly in 1924 and 1963, that match similar footprints to both the Nuns and Tubbs Fire. However, there's no question that these fires are beyond the extent of any historical fire. To answer the question, "why?", a collaborative effort was created through Ag and Open Space Sonoma County with Kass Green & Associates with Tuckman Geospatial. Their hypothesis was the changes in the landscape, such as slope, vegetation, wind and ladder fuels, were responsible for heightened intensity and spread of the fires. With funding assistance through NASA, the research team investigated the relationship between damage to the landscape (woody canopy) and variations across the landscape. Using machine learning, the research team looked at 72 landscape variables, including ladder fuels, canopy height, wind direction and speed, and distance to streams. 

Out of the six scenarios (each of the three fires being divided by wind driven events and topography driven events) their machine learning algorithm found high density of ladder fuels, low canopy height (shrubs), low climatic water deficit (precipitation and overall moisture), and far distance from streams all correlated to high damage to the landscape. A large takeaway from these results is the importance of ladder fuels in intensifying wildfires. Ladder fuels are the accumulation of woody vegetation (fuel) underneath a forest or shrub canopy. From these ladder fuels, fire can "climb" from lower growing woody vegetation up into the canopy, causing a high-temperature crown fire. The fire prevention community has known ladder fuels increase the risk and intensity of wildfires for a long time. This study not only verifies this case, but also provides something greater—a means of mapping the ladder fuels through Sonoma County. With this map, Sonoma County is able to find and manage for ladder fuels, focusing on escape routes, homes and buildings. 

For San Mateo County, we still have a few years to wait before we can create similar resources. Starting in Summer 2019, the data will be coming out piecemeal, like LiDar, 1-ft contours, and ladder fuels, but the final package is slated for 2022. Once fully produced, these maps will provide critical information to fire prevention agencies, such as Fire Safe San Mateo County, in planning escape routes, creating targeted fuel reduction projects around fire prone communities and so much more. 

Special thank you to Danny Franco (Golden Gate National Parks Conservancy), Deborah Hirst (Board of Supervisors for District 3), Supervisor Don Horsley, Denise Enea (Woodside Fire Protection District and Fire Safe San Mateo County Board President) and the good folks at Woodside Town hall for all your work in creating this workshop.

For more information on the San Mateo vegetation mapping project, please contact Daniel Franco at This email address is being protected from spambots. You need JavaScript enabled to view it.. Power point presentation from the day's presentations are available here:

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