Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Fire

The Effects of Changed Fire Regimes on Mt. Tam

Mt. Tam has not seen a large, stand-replacing fire for over 70 years due to fire suppression policies and practices. While fire suppression is important for protecting local air quality and nearby property, the removal of fire is resulting, in part, in the succession of grasslands to shrublands, shrublands to woodlands, and woodlands to Douglas-fir (Pseudotsuga menziesii) dominated stands. Fire suppression also has implications for the regeneration of fire-dependent species, such as Sargent cypress (Cupressus sargentii) and Marin manzanita (Arctostaphylos virgata).

Disease Impacts

In addition to these direct impacts, changed fire regimes and fire suppression are interacting with other ecological stressors on Mt. Tam in a variety of ways. Higher fuel loads resulting from trees killed by Sudden Oak Death may increase the intensity of any fires that occur. Large fires burn hotly, and can kill large numbers of trees over a wide area. This both releases nutrients into the soil and increases the amount of light reaching the ground, conditions that can be exploited by non-native, invasive plant species (LCA, 2009).

Climate Change Considerations

Climate change is expected to generally cause an increase in wildfires, but underlying factors can combine in ways that make the specific effects difficult to predict. In general, drier and warmer conditions are more favorable to fires. Fire frequencies are projected to increase on the order of 20 percent for Mt. Tam under projected climate scenarios (Micheli et al., 2016).

Although models predict more intense fires, fire suppression policies will continue to maintain the mountain's fire regime in an altered state. This will likely lead to infrequent but large and intense wildland fires driven by extreme fire weather that will burn many acres despite efforts to control them.

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Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Ecological Processes and Stressors

Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Coast Redwood Communities

Summary

Old-growth coast redwood forest communities are doing well, but second-growth redwood forests, which make up the majority of the redwood forests on Mt. Tam are in Fair condition with an overall Declining trend.

Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Open-canopy Oak Woodland Communities

Summary

Open-canopy oak woodlands are in Fair condition, with a Declining trend, mostly due to invasive species, Sudden Oak Death, and Douglas-fir (Pseudotsuga menziesii) encroachment.

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Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Grassland Communities

Summary

Grassland communities on Mt. Tam are in Fair condition with a Declining trend. These areas have been relatively stable based on a recently assessed baseline for the total extent of grassland communities. However, Douglas-fir (Pseudotsuga menziesii) and coyote brush (Baccharis pilularis) recruitment into the edges and interior of some grassland patches mean that the overall patch size and number of large patches is below the desired condition. The presence and relative dominance of invasive, non-native grasses and forbs is further causing grassland habitat quality decline.

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Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Shrubland Communities

Summary

Coastal scrub and chaparral communities are in Good condition with No Change in their overall trend. They have been stable and show no major negative signs from the impacts of ecological stressors that are affecting many of Mt. Tam’s other plant communities such as invasive species, or Douglas-fir (Pseudotsuga menziesii) encroachment. Their extent has remained fairly stable and the have a full complement of associated bird species.

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Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Ecosystems

Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Biodiversity

Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Landscapes

Mt. Tam

Wednesday, December 31, 1969, : Park Stewardship Marin

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Event Type: Educational and Interpretive

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