LA’s Trees Absorb More Carbon Than Expected, But Can’t Do It Alone

A USC study finds that Los Angeles’ urban trees absorb more carbon than expected, but while they provide crucial environmental benefits, they cannot replace the urgent need for systemic emissions reductions.

2 minute read

February 28, 2025, 8:00 AM PST

By Clement Lau


A groundbreaking study from USC Dornsife College has found that trees in central Los Angeles absorb significantly more carbon dioxide than previously estimated, offsetting up to 60 percent of daytime fossil fuel emissions in the warmer months and about 30 percent annually. Using an innovative network of high-resolution CO2 sensors called the Carbon Census array, researchers tracked emissions in real time, providing one of the most detailed measurements of how urban greenery impacts air quality. Unlike traditional models that estimate CO2 levels indirectly, this study measured carbon emissions directly over an 18-month period, yielding a more precise understanding of how vegetation interacts with urban pollution.

One of the most surprising findings was that trees absorbed the most carbon dioxide during summer, despite the season’s dryness. Researchers attribute this resilience to irrigation, groundwater access from leaky infrastructure, and drought-resistant tree species. However, while urban trees play a critical role in improving air quality, they cannot fully offset emissions from cars, buildings, and industry. CO2 levels still spiked during rush hours, reinforcing the need for broader systemic changes. The study supports the USC Urban Trees Initiative, which seeks to expand greenery in communities most in need, using data-driven insights to guide tree planting efforts where carbon absorption is highest.

Looking ahead, researchers are expanding the sensor network to cover more areas of Los Angeles, helping to define baseline CO2 levels and identify regions where vegetation can make the biggest impact. While urban trees provide a natural boost to carbon reduction, lead researcher Will Berelson emphasizes that they are not a substitute for larger climate solutions. “Nature is helping us, but we can't rely on it to do all the work," he said, underscoring the need for clean energy, better public transit, and broader emissions reductions to meet the city’s goal of carbon neutrality by 2050.

Tuesday, February 25, 2025 in Phys.org

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Get top-rated, practical training

Historic homes in St. Augustine, Florida.

Florida Considers Legalizing ADUs

Current state law allows — but doesn’t require — cities to permit accessory dwelling units in single-family residential neighborhoods.

March 18, 2025 - Newsweek

Aerial view of suburban housing near Las Vegas, Nevada.

HUD Announces Plan to Build Housing on Public Lands

The agency will identify federally owned parcels appropriate for housing development and streamline the regulatory process to lease or transfer land to housing authorities and nonprofit developers.

March 17, 2025 - The Wall Street Journal

Close-up of traffic congestion from behind cars on a freeway in the San Francisco Bay Area.

Conservatives’ Decongestion Pricing Flip-Flop

When it comes to solving traffic problems, the current federal administration is on track for failure, waste, and hypocrisy.

March 17, 2025 - Todd Litman

Close-up of rear car bumper in traffic on freeway.

Research Shows More Roads = More Driving

A national study shows, once again, that increasing road supply induces additional vehicle travel, particularly over the long run.

5 hours ago - Road Capacity as a Fundamental Determinant of Vehicle Travel

Close-up of "City Hall" plaque on building with gold lettering on black.

Can Progressive Planners Appeal to Conservative Principles?

Trump’s approach to policies like NYC’s congestion pricing isn’t just irrational and wasteful — it defies the tenets of conservatism. But there are ways to reframe the issues.

7 hours ago - Bloomberg CityLab

Close-up of seedling sprouting from ground with blurred people gardening in background.

Oak Park Plans Earth Month Events

Join Oak Park, Illinois, for a series of Earth Month events highlighting the importance of community engagement and education, integrating sustainability into local plans, and planning for the most vulnerable, such as birds, bees and butterflies.

March 23 - Local Government Commission