- Author: Glen Martin
Reprinted from California Magazine
Vista View at North Sonoma Mountain Regional Park // Detail of photo courtesy of harminder dhesi / flickr
When the Tubbs and Nuns wildfires exploded across Sonoma County in 2017, firefighters found they lacked critical information. Details on the vegetation, structures, and roads distributed across the landscape would have helped them better evacuate residents and allocate fire suppression resources.
It was only after the fires were extinguished that authorities realized much of that data was available—in the form of “veg maps.” Created by the Sonoma County Agricultural Preservation and Open Space District, Ag + Open Space as it's known locally, the maps deconstruct the terrain, depicting slope, aspect, soil type, hydrological qualities, buildings, roads and driveways—even the density of trees and brush—in exquisite detail.
Fine-scale vegetation map of Sonoma County // Image courtesy of Sonoma County Ag + Open Space
Such maps, officials realized, could be an immense asset when responding to wildfires. They could even serve a preventative purpose: helping “fireproof” undeveloped land by turning open space from a wildfire liability to a fire-prevention asset.
The maps are produced through LiDAR, or Light Detection and Ranging, which is kind of like radar, except it uses pulsed lasers emitted from aircraft or satellites instead of radio waves. The process yields precise 3-D maps of the earth's surface, detailing vegetation type and density. Researchers can look at a LiDAR map and evaluate “fuel ladders”—deadwood on the forest floor combined with the limbs and branches running from the ground to the tree tops—in any given stand of trees, down to resolutions of one centimeter.
“Using the maps for wildfire response wasn't our original intent,” says Karen Gaffney, a UC Berkeley alumna and the conservation planning manager for Ag + Open Space. Originally part of a project supported by the Sonoma County Water Agency and grants from NASA, the maps were created for land and wildlife conservation purposes. “But it just so happens much of that data is proving valuable for disaster planning.”
The maps are being used to flag the best fire evacuation routes and the sites most susceptible to contamination or erosion post-fire.
When it comes to wildfire, it's largely about fuel. While the forests of the West were once subject to regular low-intensity fires that produced large, well-spaced trees and light accumulations of deadwood, more than a century of overzealous wildfire suppression and rising temperatures from climate change have reversed this dynamic. Combine the current dense, thicket-like stands of trees and piles of dead branches with hot, dry autumn winds, and the result is wildfires of devastating ferocity—wildfires like the 2017 North Bay fires and the 2018 Camp Fire in the town of Paradise.
Like many areas, Sonoma County has been attempting to use “prescribed” fire and tree thinning to reduce fuel loads, says Gaffney. Shortly before the Nuns Fire ripped through Glen Ellen, an experimental prescribed burn conducted at a nearby ranch demonstrated the effectiveness of such efforts. The encroaching wildfire immolated nearby woodlands and structures, but dropped to low, flickering flames when it hit the prescribed burn zone. There simply wasn't the fuel to sustain it.
The message was clear to the county's disaster response planners: the more wildlands that can be burned under controlled conditions, the better.
The district's veg maps are now being used by county officials to identify candidate open spaces for thinning and prescribed fire, with prioritization going to the most vulnerable areas.
“In conjunction with our partners at Pepperwood Preserve and Tukman Geospatial, we've created fuel loading maps from our LiDAR data that identify areas where heavy ladder fuels are located close to structures,” says Gaffney, who declined to comment on specific sites. “And because we can map development footprints down to resolutions of one centimeter, we can even identify risks for individual buildings.”
Ladder fuels maps of Sonoma County // Image courtesy of Sonoma County Ag + Open Space
The maps are also being used to flag the best fire evacuation routes and the sites most susceptible to contamination or erosion post-fire.
“For example, we can determine if a [burned] structure that contained toxic materials is at significant risk of contaminating a nearby stream,” Gaffney says. “While the maps first responders and firefighters typically use show all the major and secondary roads, our data let us create maps that show the much smaller routes that could also be used for evacuation.”
The veg map approach to wildfire response and planning is gaining fans beyond the borders of Sonoma County.
“Marin County and San Mateo County have acquired LiDAR technology and are creating their own veg maps,” says Allison Schichtel, the conservation GIS coordinator for Ag + Open Space, “and Monterey and Santa Cruz Counties are looking into it. I did a presentation at a forestry and GIS workshop, and there were folks from [far] northern California and southern Oregon who wanted to know all about it. Interest is growing—kind of like an amoeba.”
- Author: Susie Kocher
- Author: Kim Ingram
- Editor: Sophie Kolding
The 2004 Sierra Nevada Forest Plan Amendment that guides the management of the national forests in the Sierra has been ripe with controversy since its inception. Disagreements over harvesting plan details, the effectiveness of SPLAT fuels treatments and their effects on wildlife and water issues led to the formation of the Sierra Nevada Adaptive Management Project (SNAMP) as a way to address these controversies and learn from the best available science. The US Forest Service, US Fish & Wildlife Service and California Resource agencies contracted with the University of California to be an independent, neutral third party to research key management issues, develop a multi-party adaptive management program that builds on new research and to increase public participation in all aspects of the project. UC scientists are working in five areas: Fire & Forest Ecosystem Health, Water Quality & Quantity, Wildlife (CA Spotted Owl and Pacific Fisher), Spatial, and Public Participation. These teams are conducting scientific research in an open and transparent manner to measure physical and natural processes at relevant management scales, all the while integrating competing public interests, identifying conflicting outcomes and building public trust. The overall goal of this seven year project is to provide the Forest Service and resource agencies with quality information derived from deliberate experimentation that can be used to improve future management decisions and reduce conflict.
SNAMP has two study sites, Last Chance in the northern Sierra and Sugar Pine in the southern Sierra. These sites were selected because they represent the major bio-geographical features of the Sierra Nevada. They have mixed conifer forests with suitable control and treatment watersheds and old forest habitat for species at risk. They are also large enough to support fireshed scale research and active planning by local Forest Service districts for fuels management projects. Two to four years of pre-treatment data has been collected by the UC teams prior to the start of fuels reduction treatments (including thinning, mastication and prescribed fire) that began during summer 2011. Treatments are scheduled for completion by late 2012.
Logs being sorted at the Last Chance thinning project near Foresthill, CA, September 2012.
Photo by Shufei Lei
Analysis of pre-treatment data has led to some initial findings from the various UC science teams. The Forest Team collected data on tree size and species, as well as fuel loading in the study area, then modeled how fire behavior would be affected both before and after the treatment. They predict that both treatments will be effective at moderating wildfire behavior. They also analyzed hundreds of tree core samples and compared growth patterns between live and dead trees. Initial evidence suggests that thinning can improve tree growth even under adverse environmental conditions such as drought.
Photo by Susie Kocher
The fisher team has used radio collars to track the movements and dispersal of over 66 Pacific fishers in the Sugar Pine area. By retrieving fisher carcasses, the team, in conjunction with UC Davis scientists, has identified the top four causes of fisher mortality in the study site: predation from bobcats, mountain lions and coyotes, disease, rodenticide and road kill. They are currently developing measures of the population dynamics for the species, including reproduction and survival as well as locations of fisher source and sink areas in the study area.
The CA Spotted Owl Team has identified 75 owls in 48 territories within the SNAMP study area. Using data from monitoring territory occupancy and reproductive success of the owls, initial findings suggest that the owl population is in an overall decline. The team is conducting a retrospective analysis on the history of land use and vegetation looking at all observable changes in owl habitat due to disturbance to identify potential causes of decline.
With meteorological and hydrological instruments, the Water Team records and collects data on a daily basis. This data is fed into computer models to produce potential trends in stream discharge and sediment loading or snow accumulation and snowmelt rates. Using different parameters, such as a reduction in leaf area index (LAI), the team is modeling effects of fuels treatments on stream flows and evapo-transpiration rates.
Remote sensing of both study areas was done using Lidar (light detecting and ranging). This data has allowed the Spatial Team to produce many two and three dimensional maps and other products for use by the science teams. Examples include bare earth, slope, aspect and elevation maps; canopy cover and LAI maps; as well as providing information incorporated into fire behavior models. The team has developed methods to detect individual trees from a lidar data point cloud and has used this data to characterize habitat structure for the wildlife teams.
Digital elevation model and vegetation layers Visualization of forest structure developed by the SNAMP
developed by the UC Spatial Team Spatial Team using Lidar data
The role of the Public Participation team is to promote SNAMP through strategic facilitation and outreach and to support the progress of adaptive management. The team reaches many diverse participants through meetings, field trips and workshops; presentations to community leaders and groups; submissions to blogs, industry publications and other media outlets; and the SNAMP website. Current work includes papers on perceptions of forest health, social network analysis and lessons learned through outreach.
of the Last Chance Project near Foresthill. Photo by Shufei Lei.
Funding difficulties affected the scope of the project in 2011. However, the majority of funding has been restored and the project will be completed with a few changes to the original scope of work.
Data collection by these teams will continue for a year after the fuels treatments are complete in order to characterize the effects of the treatments on forest health, fire, water, and wildlife. There will be a final report to agency partners and the public in 2014. For more information, please see the SNAMP website http://snamp.cnr.berkeley.edu/.