As of March 30th, 2020, The City of Beverly Hills has been taking measures to provide a 30-foot defensible space from identified highly flammable public trees to structures located in the Very High Fire Hazard Severity Zone area (VHFHSZ). These areas within the City of Beverly Hills have been identified as having a high wildfire hazard or risk by the State (Cal Fire.) The Very High Fire Hazard Severity Zone interactive map is shown here http://www.beverlyhills.org/fdbrush.
To provide a better understanding on the conditions of the VHFHSZ area, Dudek was hired to assess the overall conditions and provide recommendations. Based on the Dudek report, the following recommendation were made.
First, the report recommended breaking up continuous fuel chains that lead from wildlands to structures or even non-wildland edges of property to structures. The report referenced a widely accepted standard of keeping highly flammable trees no closer than 30 feet from structures.
- “It is recommended for properties in Trousdale Estates that the City’s fuel modification requirements are applied and enforced. Because many of the structures on the lots are less than 60 feet apart, the entire sideyards should be considered the structure protection zone. Trees in the first 30 feet may be allowed if they are not of higher flammability types, are highly maintained, and are provided at least 10 feet of vertical and horizontal separation from the structures” 1
- “A widely acceptable standard is that these types of flammable trees should be no closer than 30 feet (edge of tree crown) from adjacent structures, but it is considered safer to minimize these trees within the first 100 feet, even when they are provided maintenance” 2
Second, the report made recommendations on how to improve the safety of evacuation routes due to the conditions and types of highly flammable trees located along evacuation corridors.
- “Because the trees are along critical evacuation corridors, it is recommended that the trees that are noted to include health or structural maladies should be removed and replaced with an appropriate species.” 3
- “Wildfire risks in Trousdale Estates included potential for short-timeframe wildfire warning due to a nearby fire start (such as north in the canyons), high number of residences and related population, and evacuation routes that could be quickly congested.” 4
- “Benedict Canyon Drive and San Ysidro Drive Specific Recommendations
- Prune tree crown’s hanging over roadways back to provide clear to the sky access.
- Consider removal of trees overhanging the road travelways. The tree crowns hanging over the road travel way and represent a potential issue during evacuation and may not be able to correct through pruning.” 5
Lastly, the report included the removal of City highly flammable trees along Carla Ridge that are stressed, declining, exhibit poor branch architecture or other maladies as well as other highly flammable tree species located in the VHFHSZ area. It Identified that Cedar, Cypress, Eucalyptus, Juniper, Palm, and Pine were more susceptible to specific characteristics stated below.
- “Some tree species are more flammable than others and may propagate the spread of a wildfire. In relation to this study of urban trees, the tree type, such as Cedar, Cypress, Eucalyptus, Juniper, Palm, and Pine, were identified as more susceptible to burning, due to rough or peeling bark, production of large amounts of litter, vegetation that contains oils, resin, wax, or pitch, or tree canopies that inherently include a high dead to live fuel ratio. (e.g., large amounts of dead material in the tree canopy). These trees are widely considered by fire agencies as undesirable and deemed less resistant to ignition.” 6
- “Pine trees are considered among the top priorities for reducing fire hazards, particularly on private properties, but also on public properties including evacuation corridors.” 7
- “The City-owned Canary Island pine trees are in moderate, but declining health. There are numerous trees with structural maladies, including previous tree topping, which has resulted in poor structure and stressed conditions. Trees on Carla Ridge exhibit the highest level of stress and decline. Many of the declining pines on either side of Carla Ridge have been removed as indicated by several vacant tree planting spots and many more will require removal in the short or mid-term due to their declining or poor overall conditions. Additionally, the slopes adjacent to much of Carla Ridge create a circumstance where creating crown separation from understory plants is difficult or impossible. The tree crowns are situated too close to some adjacent homes.” 8
- “Although these efforts have reduced the areas fire vulnerability, concerns remain, primarily due to the existence of transitional fuels in the form of dense landscapes, including the use of tree species that are considered highly flammable in close proximity to residences and other structures.” 9
The City is currently taking measures to address all the recommendations from the Dudek report in hopes it will provide safer evacuation routes for the community, provide safer conditions for fire suppression, reduce the high risk of fire to low risk, help minimize potential loss to structures and decrease the chances of a major conflagration occurring in the wildland urban interface (VHFHSZ) area.
- “Modified fuel areas work because highly flammable species are removed, vegetation densities are reduced, plants are kept hydrated and healthy, and appropriate setbacks are provided so that if plant ignites, it will be less likely to compromise the property’s residence.” 10
For additional information and updates pertaining the VHFHSZ Public Tree Removal and Replacement program please click here.
*As of 4/3/20, the Public Tree Removal Program has been placed on hold until further notice.
1 Dudek Report Page 47 Section 18.104.22.168 – Trousdale Estates Tree Recommendations; 11868 Dec. 2019
2 Dudek Report Page 16 Section 2.6.5 – Private Property Tree Related Fire Hazards; 11868 Dec. 2019
3 Dudek Report Page 44 Section 22.214.171.124 – Evacuation Corridor Tree Management Recommendations; 11868 Dec. 2019
4 Dudek Report Page 21 Section 2.8 – Trousdale Estates Tree Related Fire Hazards; 11868 Dec. 2019
5 Dudek Report Page 46 Section 5.4 – Watering; 11868 Dec. 2019
6 Dudek Report Page 27 Section 4.1 – Higher Flammability Trees; 11868 Dec. 2019
7 Dudek Report Page 29 Section 4.1.1 – Conifers; 11868 Dec. 2019
8 Dudek Report Page 21 Section 2.8 – Trousdale Estates Tree Related Fire Hazards; 11868 Dec. 2019
9 Dudek Report Page 1 Introduction; 11868 Dec. 2019
10 Dudek Report Page 16 Section 2.6.5 – Private Property Tree Related Fire Hazards; 11868 Dec. 2019