The Green Divide

In the heart of every great city lies its parks—spaces where the morning dew still remembers to gather, where children's laughter rises above the urban symphony, and where strangers become neighbors over shared moments on sun-warmed benches. These green sanctuaries serve as the living rooms of our cities, where daily life unfolds against a backdrop of trees, grass, and open sky.

The importance of public parks and green spaces extends far beyond their aesthetic value. Research has consistently demonstrated their critical role in public health, with studies linking park access to improved cardiovascular health, reduced stress levels, and enhanced mental well-being. Despite these documented benefits, Los Angeles faces significant challenges in its park system, ranking #88 out of the 100 most populated US cities according to the  Trust for Public Land's 2024 ParkScore Index , the nation's most comprehensive evaluation system for city park systems. This deficit in green infrastructure is not distributed evenly across the region. In Los Angeles County, historical patterns of development and investment have shaped a stark urban reality where park access varies dramatically—some neighborhoods enjoy abundant green spaces while others face severe shortages in both park acreage and accessibility.

In 2015-2016, the Los Angeles County Department of Parks and Recreation launched the  Countywide Park and Recreation Needs Assessment (PNA) , the most comprehensive survey of park needs in the region's history. Building upon this foundational work, this study focuses specifically on urban areas within Los Angeles County, defined by the  Census Bureau (2020)  as regions with a household density of more than 200 per square mile. This targeted approach allows for a detailed examination of park access in the county's most densely populated areas, where the need for public green spaces is often most acute.

Drawing on the  National Recreation and Park Association 's (PNA) definition of park access—which encompasses both adequate acreage and reasonable proximity to parks and green spaces—this study evaluates park accessibility through three interconnected metrics: acreage, proximity, and park pressure. By analyzing these spatial patterns alongside demographic and socioeconomic factors, we can better understand how parks serve—or fail to serve—different communities across Los Angeles County's urban landscape.

The primary datasets for this study are the  Countywide Parks and Open Space dataset , which provides comprehensive information about public park locations and boundaries, and the  2020 Census Data with Demographic Characteristics , which contains population and household density information at the census tract level. Both datasets are hosted on the  County of Los Angeles Open Data platform  and provide the foundational data for analyzing park accessibility patterns across different urban densities.

This study employs a multi-step analytical approach using ArcGIS and QGIS to process and visualize park patterns across urban LA County. Initial data preparation involved standardizing park polygon geometries, integrating census demographic data, and removing incomplete or anomalous observations to ensure data quality and consistency.

The analysis of park access was conducted through three distinct metrics, each requiring specific spatial analysis techniques:

• For  park acreage , park polygons were intersected with census tracts using Vector Overlay tools to determine total park area per tract. This data was then normalized to calculate park acres per 1,000 residents using Field Calculator, with null values set to zero for tracts lacking parks.
• For  park proximity , half-mile buffer zones were created around parks using the Buffer tool to represent 10-minute walking distances. These buffers were then intersected with census tracts to calculate the percentage of accessible area within each tract.
• For  park pressure , Thiessen polygons were generated from park centroids using QGIS's Vector Geometry tools to establish park service areas. Population distribution within these service areas was then calculated through area-weighted interpolation of intersecting census tracts.

Meanwhile, statistical analysis and data visualization were performed using Python libraries including Pandas and NumPy for data manipulation, and Plotly for interactive graphical representations.

This study adopts PNA's classification system for parks and open spaces, which categorizes them into four types based on their size and available amenities: local parks, regional recreation parks, regional space, and natural areas. Natural areas, while valuable for preservation, are excluded from this analysis as they typically lack the developed facilities that make parks accessible for everyday use.

In evaluating park resource distribution, this study first employs the widely accepted metric of acreage per 1,000 residents, a standard also used by the  California Department of Parks and Recreation . This standardized measure allows for meaningful comparisons across different neighborhoods and helps identify areas that may be underserved by park space relative to their population density.

More than 4 out of 5 neighborhoods in urban Los Angeles have inadequate park access.

Across Los Angeles County's 2,496 urban census tracts, the average park space is 4.1 acres per 1,000 residents—a figure that masks deep inequalities. While this exceeds the county-wide average of 3.3 acres, a closer look reveals a troubling pattern: 82.8% of the census tracts fall below the state's minimum threshold of 3 acres per 1,000 residents, a standard established by the  Statewide Park Development and Community Revitalization Act  to identify areas experiencing park poverty.

Even more striking, only a few privileged neighborhoods—less than 7% of urban tracts—meet the  Department of City Planning 's recommended standard of 10 acres per 1,000 residents. This means that in most communities, residents must compete for limited park space, turning what should be places of relaxation into contested territories.

While raw park acreage provides a foundation for understanding access, physical proximity fundamentally shapes how residents interact with these spaces.  The Trust for Public Land's ParkScore® index  has established a standard of a 1/2 mile radius—equivalent to approximately a 10-minute walk—as a reasonable threshold for defining adequate park access. This distance represents a practical limit that most people are willing to travel regularly on foot to reach recreational spaces, beyond which usage rates typically decline substantially.

While acreage and proximity are essential metrics for park access, they must be contextualized within population and usage patterns, as a park that appears adequate in size and location might be overwhelmed if serving too large a population. To assess this dimension, this study adopts the Park Service Area (PSA) method, which assumes residents utilize their nearest park at a uniform rate. Park acreage per 1,000 residents is again used here as an indicator of potential usage intensity – service areas with lower acreage per 1,000 residents are more likely to experience congestion.

The results paint a troubling picture of overcrowding across the urban landscape. Using the urban sector average of 4.1 acres per 1,000 residents as a benchmark, we find that nearly three-quarters of parks (73.02%) in urban areas are under high pressure, struggling to serve too many residents with too little space. Only about one in four parks (26.98%) have enough breathing room to adequately serve their communities.

As this study reveals, Los Angeles County's urban park system tells a complex story of space, distance, and density. Through our three key metrics—acreage, proximity, and park pressure—we see a landscape where green space distribution remains notably uneven. Over 80% of urban census tracts fall below the state-designated threshold for adequate park space, while only half of urban residents have a park within walking distance. Nearly three-quarters of existing parks operate under high population pressure, straining to serve more residents than their acreage suggests they should.

These statistics reflect the daily reality of thousands whose access to nature and recreation varies dramatically by neighborhood. However, reality always introduces more nuances and challenges. The ongoing wildfires in Los Angeles have been raging in areas rich with green resources, once again highlighting the complex local challenges faced by a region prone to natural hazards. How can we address these layered challenges while ensuring equitable access for all? What does true accessibility mean in the face of such complexity?

Moving forward, this emerging relationship between environmental hazards and park accessibility demands a reconceptualization of how we measure and plan for park access. Traditional spatial metrics alone may no longer suffice in capturing the full complexity of park accessibility in our changing climate. This suggests a need for more dynamic and temporally aware methodologies in urban park planning, ones that consider not just the physical distribution of parks, but also their year-round accessibility and resilience to environmental challenges.