Photo Credit

USDA Forest Service

LA Urban Center as seen through the trees of the plaza at El Pueblo De Los Angeles Historical Monument. 

In the last few months, the U.S. Forest Service (USFS) has made historic investments in urban forestry. Funding from the Inflation Reduction Act (IRA) will go a long way towards investing in tree cover in the nation’s communities, but the USFS Research and Development arm has another role in urban forestry – supporting our partners through collaborative research to inform management. The Pacific Southwest Research Station’s service area is home to two large urban zones where we work with stakeholders and key partners in the Sacramento-San Francisco metro and Los Angeles metro areas. The city of Los Angeles is of particular interest, as the second largest city in the U.S., with nearly 4 million people in the city proper, and well over 10 million in the LA metro area. Los Angeles is also home to a collaborative hub, known as the Los Angeles Center for Urban Natural Resources Sustainability, or the LA Urban Center. The LA Urban Center is a unique partnership between USFS Research and Development; State, Private and Tribal Forestry; the National Forest System, and the City of Los Angeles. Forest Service urban center hubs, like the LA Urban Center, are key for place-based knowledge exchange and interdisciplinary research on social and ecological issues impacting our partners and the communities.

The Pacific Southwest Research Station is supporting studies in these urban zones along with investments from the USFS Pacific Southwest Region; State, Private, and Tribal Forestry; and our state and local partners. One such example is a schoolyard tree study led by PSW research urban ecologists Dr. Lara Roman and Dr. Natalie Van Doorn, in partnership with CAL FIRE and a nonprofit organization called Green Schoolyards America. This project aims to inform the management of trees in public schools. PSW scientists and their collaborators will evaluate the impact of trees on their surroundings, like providing shading and cooling. Roman and Van Doorn are also investigating the vulnerability of campus trees to climate change and demystifying the tree maintenance and implementation process, creating a better understanding of the barriers and challenges associated with managing and maintaining school yard trees.

Another effort, led by Research Social Scientist Dr. Francisco Escobedo and Statistician Dr. Nels Johnson, will examine the role of tree and shrub moisture, location relative to buildings, and condition in wildfires in urban neighborhoods. This problem of plant species type, condition, and maintenance in urban areas continues to pose problems as urbanization grows in the Western U.S., increasing wildfire risks for people and property. This study will provide context for the role of tree and shrubs in building loss, informing knowledge of landscape management in at-risk communities, inform how urban and wildland urban interface areas are changing amid urbanization, and improve our messaging in these communities for when the need arises.

Photo Credit

USDA Forest Service

View surrounded by trees at the plaza at El Pueblo de Los Angeles Historical Monument, with LA City Hall in the backdrop.

Around the Station

Understanding Urban Tree Canopy in Hawai‘i

Drone image of Waianae Canopy, captured by USFS partners for Region 5. 

In partnership with the Forest Service, the Hawai'i Kaulunani Urban and Community Forestry Program launched a Tree Canopy Viewer website which includes spatial information on tree cover, heat index, health, socioeconomic, and demographic conditions. The partnership also supported four fellows, including Chanel Yee, to conduct research on urban trees, communities, equity, and land management planning using the Tree Canopy Viewer data. For her fellowship Chanel examined the existing landcover within areas of projected urban expansion in North Kona and South Kohala on Hawaiʻi Island. Her research revealed a great need to incorporate and align wildfire mitigation goals into state, county, and district land management plans that reflect the relationship between land cover change and wildfire risk. Chanel found that projected development will encroach on and expand communities that bear wildfire risk as well as the Wildland-Urban Interface (WUI) that exist within landscapes dominated by fire-prone non-native grasses. Given that almost all wildfire ignitions in Hawaiʻi are human-caused and most ignitions occur in populated areas, future development in areas of dense fire-prone vegetation will likely increase communities’ wildfire risk. However, urban expansion also provides an opportunity to restore and use native tree species canopies which can reduce wildfire risk and promote ecological, social, and cultural land values for Hawaii’s future generations.

You can learn more about the Tree Canopy Viewer Fellows’ research and perspectives on Hawaii Public Radio (external link) and the Hawaiʻi Division of Forestry and Wildlife website (external link).

Webinars & Events

Webinar Recordings

Pacific RISCC Webinar: Resilient Blue Carbon Ecosystems, Resilient Coastlines, Resilient People

Dr. Richard MacKenzie

PSW Research Ecologist

This webinar covered:

Research on the vulnerability of Pacific Island nations to climate change and how appropriate adaptation actions can increase the resilience of mangroves and thus the resilience of Pacific Islanders.

Webinar Recording (External Link)

 SCIENCEx Genetics Week

January 29th - Feb 1st was SCIENCEx Genetics week. Forest Service researchers shared about work happening across the country on fish and wildlife research, landscape restoration, climate change perspectives, and research applications. Find the link of previous SCIENCEx recordings focus weeks below.

SCIENCEx Webinar Archive

Station News

Megafires Take a Toll on California Wildlife

From 2020-2021, megafires tore through California, scorching more than 4.2 million acres. The fires were like none ever recorded in modern history. Their devastation of human communities was well-documented, but their toll on wildlife was largely unknown.

Read More

PSW Foresters Earn 2023 Distinguished Science Award

Foresters Martin Ritchie and Jianwei Zhang have noteworthy careers with the Pacific Southwest Research Station. Between them, they have published close to 200 technical reports that address contemporary and challenging forest science questions, earning them the 2023 Distinguished Science Award.

Read More

External Media

Golden State Naturalist Podcast: TEK (Traditional Ecological Knowledge/Indigenous Ecological Knowledge) with Frank Lake
 

In this episode, Frank Lake discusses mutualistic relationships between Indigenous Californians and the land, traditional burning, oak orchards, the powerful ways Indigenous and Western knowledges can come together, common misconceptions about pre-colonial California, reciprocity, and how we can move from a mental model of scarcity to cultivating a shared abundance that leaves no one behind. 

Listen at: Golden State Naturalist (External Link)

Publication Highlights

More PSW Publications via Treesearch

Pacific Southwest Research Station

The Pacific Southwest Research Station (PSW) was founded in 1926 as a part of the Research and Development branch of U.S. Forest Service. Since its inception, PSW has expanded to serve California, Hawai'i, and the US-affiliated Pacific Islands. PSW develops and delivers science-based information, technologies, and applications to help people make informed decisions about natural resource management, conservation, and environmental protection.

Fact and Trivia Corner
How many trees are in the LA Urban Forest?

While impossible to know for sure, the LA Department of Public Works, Bureau of Street Services, Urban Forestry Division estimates that there's over 10 million trees in the LA Urban area, with over 700,000 of them along the city streets.