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Forest Carbon Plan

The passage of Assembly Bill 32, the California Global Warming Solutions Act of 2006, marked a watershed moment in California’s history. By requiring in law a sharp reduction of greenhouse gas emissions, California set the stage for its transition to a sustainable, low-carbon future. Sierra Nevada forests play a critical role in achieving the state’s long-term goals, but action is needed to ensure our forests act as carbon sinks, and not carbon sources.


Assembly Bill 32 created the first program in the country to take a comprehensive, long-term approach to addressing climate change, and does so in a way that aims to reduce greenhouse gas emissions while protecting the environment and maintaining a robust economy. The 2008 Climate Change Scoping Plan, which is the framework for implementing Assembly Bill 32, recognized the important role forests play in meeting the state's greenhouse reduction goals, stating that actions should be taken to “preserve forest sequestration and encourage the use of forest biomass for sustainable energy generation.”

The overall forestry climate goal guiding the Forest Carbon Plan is to firmly establish California's forests as a more reliable long-term carbon sink, as opposed to a carbon source.

A Forest Climate Action Team (FCAT) was assembled in August 2014 to develop a Forest Carbon Plan, and the SNC is a member of this team. The Forest Carbon Plan is being developed to provide additional impetus, detail, and direction as to how forests will play a role in California’s carbon future. The plan provides an array of strategies to promote healthy wildland and urban forests that protect and enhance forest carbon and the broader range of forest ecosystem services for all forests in California. More importantly, this plan supports an opportunity for increased action by the State of California and federal, tribal, local, and non-government partners to restore our forests to a healthy, resilient state. While the benefits of healthy forests are broadly affirmed across the multiple public and private parties, protecting and enhancing these benefits is challenging, especially in light of climate change. Building upon existing efforts throughout the state and fostering additional collaborative processes to forge agreement is crucial.

The Forest Carbon Plan was posted for public review in early 2017 and SNC submitted comments. The Forest Carbon Plan is currently being finalized.


Sierra Nevada forests help regulate our climate by removing carbon dioxide from the atmosphere and storing it as carbon in the soil, branches, and trunks of trees.

However, today many Sierra Nevada forests are overgrown and unhealthy. In these forests, trees have to compete for resources like water, nutrients, light, and space, which can slow their growth and limit their carbon absorption.

In addition, these overgrown forests are more vulnerable to large, damaging wildfires, insect outbreaks, drought, and disease. Wildfires release stored carbon as plants and trees burn, and trees killed by large, damaging wildfires, insects, drought, and disease become carbon emission sources as they decay, contributing to the state’s greenhouse gas emissions rather than offsetting them. Dead trees stop removing carbon dioxide from the atmosphere and vegetation that returns can take decades, if ever, to restore the same level of sequestration and carbon storage.

Some areas burned by high-severity wildfire may grow back as shrubs rather than forest, storing less than ten percent of the carbon that healthy forests store.

Overgrown forests are more susceptible to high-severity wildfire, insects, drought, and disease, making them a less reliable carbon sink


California has experienced an unprecedented rise in tree die-off during recent drought years. According to the U.S. Forest Service, 129 million trees have died across the state from drought, insects, and disease since 2010, and 85 percent of those dead trees are in the Sierra Nevada. Recent tree mortality will have both immediate and long-term impacts on the stability of carbon in Sierra Nevada forests.

The carbon in these trees will slowly decay over the next few decades, or be quickly released in future fire events.

  • The Sierra Nevada Conservancy estimates that 53 million metric tons of carbon dioxide equivalent of tree carbon shifted from the live to the dead pool due to tree mortality from beetles and drought in the Southern Sierra in 2016. Those dead trees will decay, and their emissions will equal what 11.2 million cars emit in a year.
  • Over 50 million trees – many of them large trees that were storing and absorbing large amounts of carbon – in the southern Sierra are no longer actively sequestering carbon, with nothing to replace that loss over the short-to-medium term.

The good news is that the activities that reduce the risk of large, damaging wildfires also help strengthen forests against drought and bark beetles. These activities have a carbon cost, but that cost is outweighed by the long-term benefit. Thinning and prescribed and managed fires emit carbon in the short term, but they help to store more carbon in the long term by reducing mortality due to fire and drought, and increasing the density of older, larger trees. Healthy forests, even during drought, can continue absorbing carbon from the atmosphere at a significant rate, and the larger the tree, the more carbon it will pull from the atmosphere on an annual basis.

how to stabilize forest carbon in the sierra

Photo credit: U.S. Forest Service, Pacific Southwest Research Station

Thinning overgrown forests and returning low-severity fire to the landscape can improve our forests’ ability to absorb and store carbon. The animation to the left shows tree growth before and after an aggressive thinning treatment in the northern Sierra. Thinning the forest frees up additional resources for the remaining trees, which allows them to grow more in the years following thinning efforts and absorb more carbon each year.

Additional funding, policy changes, and infrastructure are still needed to establish Sierra Nevada forests as a more reliable long-term carbon sink.

We can encourage growth of large trees, and protect the large trees that still remain on the landscape from wildfire, drought, insects, and disease, by reducing competition for resources. Large trees absorb and store more carbon, making them a more stable carbon investment for the long-term.

The Sierra Nevada Watershed Improvement Program – a partnership led by the Sierra Nevada Conservancy and the U.S. Forest Service – is working to stabilize forest carbon by increasing the pace and scale of ecologically sound restoration across the Sierra Nevada Region. The Sierra Nevada Conservancy has invested nearly $10 million in Proposition 1 funds in support of the Sierra Nevada Watershed Improvement Program, but additional funding, policy changes, and infrastructure are still needed to establish Sierra Nevada forests as a more reliable long-term carbon sink. To learn more about the Sierra Nevada Watershed Improvement Program visit