Morro Bay National Estuary Watershed Fire Management Plan

Morro Bay National Estuary Watershed Fire Management Plan

Prepared For:

Morro Bay National Estuary Program

Morro Bay, CA

Prepared By:

Barry Callenberger, Wildland Fuels Planner

Zeke Lunder, Fire Planner/Geographer

Erik Frenzel, Biologist / T&E Specialist

Robert Burnham, Fire Planner

North Tree Fire International

Division of Fuels Management/Geographic Information Systems

10674 Ramirez Road,

Marysville, Ca. 95901

MORRO BAY ESTUARY WATERSHED FIRE MANAGEMENT PLAN

Table of Contents:

Background 1

Management Goals 2

Desired Future Conditions 2

Morro Bay Wildland Fire Environment 5

Ecological Role of Fire in the Morro Bay Watershed 5

Fire History of the Morro Bay Watershed 6

Ignition Sources 6

External and Internal Fire Ignition Threats 7

Large Fire History 8

Climate and Fire Weather 8

Fire Behavior 9

Wildland Fuels 10

Current Wildland Fire Protection and Fire Management Responsibilities 12

Areas of Concern to Fire Managers 13

South Los Osos Area 13

Habitat Conservation Planning and Wildland Fuels Management 13

West Cuesta Ridge 17

Wildland Fire Management Strategies 19

Fire Management Strategies to Achieve Desired Future Conditions 19

The Use of Strategic Fuelbreaks in Fire Suppression and Fire Defense Systems 20

Community Fire Education, Fire Prevention and Fire Awareness 21

Current Ignition Management and Risk Reduction Activities 22

Resource Protection Reccommendations 22

Fuel Management Projects and Priorities 24

Fire Management Compartments/Prioritization 24

Fuel Break Construction and Maintenance 25

Prescribed Burning Projects 26

Typical Fuels Treatment Methods 27

Cerro Alto Canyon Prescribed Burns 28

Bernardo Burn 30

Microwave Burn 30

Upper Dairy Burn 31

Cuesta Ridge Botanical Area Thinning Project 35

Area Fire History 35

1994 Fire Behavior 35

Pattern of Age Classes in Sargent Cypress (Literature Review) 35

Fire Management Considerations 37

Adaptive Fuels Management Projects 39

Los Osos Wildland Urban Interface Fuels Projects 42

Strategic Pre-Fire Attack Planning 43

Fire Management Projects Priorities and Summaries 45

Special Considerations within Proposed Project Areas 59

Special Status Animal Species Likely to Occur in Project Areas 59

West Cuesta Ridge Special Status Animal Species 59

Los Osos Special Status Animal Species 60

Special Status Plant Species Likely to Occur in Project Areas 61

West Cuesta Ridge Area Special Status Plant Species 61

Los Osos Area Special Status Plant Species 63

Invasive/Exotic Plant Species 64

Invasive Species Threats in the Los Osos Area 64

Invasive Species Threats to Cuesta Ridge 66

Mitigation and Avoidance Measures for Special Status Species 69

Focused Surveys 69

Seasonality of Burning Operations 69

Potential Effects on Plants 69

Potential Effects on Animals 69

Habitat Avoidance Measures 70

Habitat Avoidance Measures for Special Status Animal Species 70

Habitat Avoidance Measures for Special Status Plant Species 71

Control of Exotic Plants 71

Species Location Information for Wildland Fire Incident Action Planning 72

Research Needs 73

Fire Management Impacts on Specific Organisms 73

Landscape Scale Processes Related to Fire Management 74

Literature Cited 76

Appendix 1: Special Status Species Accounts 84

Plant and Lichen Species Accounts and Response to Disturbance 84

Animal Species Accounts and Response to Disturbance 95

Appendix 2: TMDL Listing of Morro Bay Creeks 107

Table of Figures and Tables:

Figure A: Watershed Erosion Issues 3

Figure B: Wildland Fire Ignitions Within the Morro Bay Watershed by Cause 7

Figure C: Variety Among “Even-Aged” Stands Of Post-Fire Vegetation 11

Figure D: South Los Osos Area 15

Figure E: Los Osos Wildland-Urban Interface Issues 16

Figure F: Highway 101 And West Cuesta Ridge 18

Figure G: Surface Erosion On Cuesta Ridge Fuelbreak 28

Figure I: Cuesta Ridge Fuelbreak 32

Figure J: Cerro Alto Area Topography 33

Figure K: Cerro Alto Area – Potential Fuels Management Projects 34

Figure L: Patterning In Sargent Cypress Forest 38

Figure M: Sargent Cypress Regeneration In Botanical Area 41

Table 1: Special Status Animals in the Cuesta Ridge Area 60

Table 2: Special Status Animals in the Los Osos Area 61

Table 3: Special Status Plants in the West Cuesta Ridge Area 62

Table 4: Special Status Plants in the Los Osos Area 63

Table 5: Invasive Species Present in Project Areas 64

MORRO BAY ESTUARY WATERSHED FIRE MANAGEMENT PLAN

i

Background

San Luis Obispo County lies along California’s Central Coast, south of Big Sur and Monterey County, and north of Point Conception and Santa Barbara County. The Morro Bay Watershed drains the area south of Cuesta Ridge in the southern Santa Lucia Mountains and north of the San Luis Range.

The Morro Bay Estuary supports the most significant wetland ecosystem on California’s south-central coast. Various land use impacts in Morro Bay’s catchment area - or watershed - have caused an increase in the amount of sediment being delivered to the estuary by its major tributaries - Chorro Creek and Los Osos Creek. Excessive sediment loading into the bay was recognized as a primary concern to the long-term health of the Morro Bay ecosystem (MBNEP 2000).

In 1994 the “Highway 41 Fire” burned all of the chaparral vegetation in Morro Bay’s upper watershed (9,700 acres or 35% of the Chorro Creek watershed). The following winter, runoff from heavy El Nino rainstorms caused major rill and gully erosion on the steep, barren slopes of Cuesta Ridge. A sediment transport study conducted in 1998 estimated that the resulting “pulse” of sediment entering tributaries to Chorro Creek was a “5,000 year event” (TetraTech 1998).

This Fire Management Plan was funded to pursue vegetation management methods to prevent wildfire from burning the entire upper watershed at once. Toward this goal, the Morro Bay Comprehensive Conservation & Management Plan (CCMP) recommends the creation of a mosaic of uneven-aged chaparral stands with the assumption that this will prevent large fires in the watershed (‘SED-3’ MBNEP 1998 p. 4-44). The rationale given for choosing this approach is that it is preferable to “meter-out post-fire sediment events” rather than having large pulses of sediment delivered at once – as was the case after the Highway 41.

Northtree Fire International was awarded the Fire Plan contract in June of 2001, and was assigned to:

“Prepare a pre-fire management plan that identifies high hazard areas and potential strategies for integrating fire and fuels management into long-term ecological restoration projects within the Morro Bay Estuary watershed.”

This Morro Bay National Estuary - Watershed Fire Management Plan is the fulfillment of the National Estuary Program’s stated objective to prepare a pre-fire management plan for the Estuary watershed.

Management Goals

In the Morro Bay Watershed Fire Management Plan, several strategies are identified for implementing a wildland fire and fuels management program that:

·  Reduces the likelihood of large, catastrophic fires

·  Reduces the adverse watershed impacts of disturbance-based wildfire suppression activities

·  Incorporates wildland fire and fuels management activities into Morro Bay Estuary Watershed restoration projects

·  Increases public awareness of the linkages between wildland fire and the health of the estuary

·  Provides for a healthy estuary ecosystem, functional watersheds and fire safe communities

Desired Future Conditions

The Morro Bay Estuary Watershed is widely recognized as a unique natural area. It provides recreational, educational, and aesthetic benefits to people, and provides habitat for a number of both widespread and endemic plants and animals. A combination of unique coastal environment and isolation has resulted in the evolution of several endemic plant and animal species whose existence is necessarily bound to periodic large fires. Altering natural fire regimes in chaparral and coastal scrub vegetation has and will continue to cause major changes in these ecosystems.

While fire suppression in the 1900s elongated the natural fire return interval on Cuesta Ridge, high intensity fire is not an infrequent event in Mediterranean ecosystems (USFS, 1998). The inherently unstable nature of the Franciscan geology atop Cuesta Ridge is evidenced by large areas mapped as geologically “recent landslide deposits” at the base of the slope (Cal Poly SLO). Periodic removal of the vegetative cover by fires has periodically provided temporary opportunities for increased surface erosion in this area. While the heavy rains following the 1994 “Highway 41 Fire” delivered large volumes of sediment to the estuary, a multitude of historic watershed disturbances including mining and road building also contributed to the magnitude of this event.

The Morro Bay National Estuary Program (NEP) and other watershed partners are currently working on reducing sedimentation from a variety of sources within the watershed, and are providing sediment deposition areas within the watershed.

The following “Desired Future Conditions” provide a framework to better incorporate fire management activities into watershed-scale restoration activities.

·  Safe communities that are reasonably protected from wildfire

·  Increased watershed capacity for fire-related sediment (restored floodplains)

·  Increased public awareness of the role fire plays in maintaining natural biotic communities

·  Favorable public and agency opinion toward ecological fire use

·  Reduced watershed disturbance/soil erosion from fire suppression activities

·  Create a complex of native vegetation of different ages and composition

·  Create viable fire-adapted plant and animal species

·  Reduced economic costs associated with fire suppression and post-fire rehabilitation

Figure A: Watershed Erosion Issues

Morro Bay Wildland Fire Environment

Ecological Role of Fire in the Morro Bay Watershed

Fire has played a key role in the evolutionary drama of coastal California. Fires are a characteristic feature of the area’s Mediterranean climate. With the exception of some rare species that have evolved within refuges from frequent fire (bogs, rock outcrops), most Mediterranean organisms have adaptations for periodic fire.

Plants in the Morro Bay Watershed demonstrate a variety of life history strategies that are adaptations to intense fire (Keeley, 1977, Keeley and Zedler, 1978, Keeley and Keeley, 1977). Some herbaceous and short-lived plants require fire to clear competing plants or trigger germination (Keeley et al., 1985). Many shrubs are able to resprout only from fire-resistant roots or burls, while others germinate solely from seeds that respond to heat, smoke, and ash; some plants do both. (Keeley and Fotheringham, 1998, Keeley, 1987). Serotinous cypress and pine require wildfires to open their cones (Zedler, 1986, Vogl et al., 1977).

Interaction between fire, soils, climate, and grazing are largely responsible for landscape patterns in vegetation in the San Luis Obispo area (McMillan, 1956, Wells, 1962, Holland and Keil, 1995). Fire is the primary force that initiates secondary succession in Mediterranean ecosystems (Stephenson and Calcarone, 1999). Periodic fires kill or consume aboveground vegetation and allow early-seral species to compete for nutrients, light, water, and space. As late-seral species overtop early-seral species, the species composition and physical structure of the vegetation changes over time (Keeley and Keeley, 1981, 1984, Keeley et al., 1981).

The 1994 “Highway 41” fire burned all of the chaparral vegetation in the Morro Bay Estuary’s upper watershed, creating a homogeneous stand of even-aged brush, and compounding erosion problems during an El Nino weather event the following winter.

Using prescribed fire to create mosaic patterns of different ages and species composition within this even-aged stand would create a landscape with a greater diversity of habitats. For example, old chaparral or mixed evergreen forest is nearly impassable to large animals, but young vegetation is much more navigable. Small mammals consume the abundant seeds and soft foliage in early-seral shrub vegetation. While fires can cause the local extirpation of animals unable to escape the flames, source populations are able to re-colonize these areas.

Fire History of the Morro Bay Watershed

In order to better characterize the wildfire threat within the Morro Bay Estuary watershed, this planning process examined and analyzed fire ignition data from the San Luis Ranger Unit for the period of 1981-1999, and large fire history data from CDF and Los Padres National Forest mapping (USDA, 1998). Ignition data is compiled from standard fire reporting forms filled out for every wildland fire that occurs. Fire reports includes the fire ignition date, size, cause (if known), township, range, and section number of each fire, making it possible to evaluate the number of fire ignitions for each square mile (see Figure 3: Number of Ignitions by Section). The large fire history is digitized from aerial photographs and from USFS and CDF geographic fire occurrence databases (drawn on topographical maps), and generally shows fire occurrence larger than 100 acres in size.

Ignition Sources

Between 1981 and 1999, 294 fires originating within the watershed burned a total of 1,217 acres (See Map D, Wildland Fire Ignitions Within the Morro Bay Watershed by Cause - 1981 through 1999). The 1994 “Highway 41 Fire” was started by an arsonist outside of the watershed - in Cerro Alto Campground - and burned over 43,000 acres - (9,700 of which fell within the watershed). No lightning fires were recorded in the watershed during this period - all of the fires were human-caused. No reports exist of fires caused by campfires that started in the upper watershed. Figure B is a graph showing the primary sources for fire ignitions from 1981 thru 1999 in the watershed of these ignitions we further analyzed the locations of the ignitions and found data that points to a particular area of the watershed that is a source of the largest amount of man caused ignitions

Figure B: Wildland Fire Ignitions Within the Morro Bay Watershed by Cause

The 3,000 acres immediately surrounding California National Guard’s Camp San Luis headquarters (not including training ranges) has the heaviest concentration of fires in the watershed (103 out of 294). Vehicles or equipment caused 59 of these ignitions. The remainder was identified as “miscellaneous”.

External and Internal Fire Ignition Threats

Fires originating within the watershed do not appear to represent the greatest ignition threat to the chaparral areas of the upper watershed. Continual grazing of most of the mid-watershed grassland areas (between Highway 1 and the base of the chaparral-covered slopes) reduces fuel-loads and slows the spread of fires, as seen in Map D. A lack of motorized recreation and generally good access for fire equipment also help to keep fires in this area fairly small. The existing wildland fire organization has been able to quickly suppress nearly all of the fires that have occurred within the watershed in the last 20 years.