Growing an Equitable Future for L.A. Using GIS

Cindy Chen, M.S.,M.A., GIS Specialist (City Plants), GIS Intern (StreetsLA)�

Rachel O’Leary, Program Director, City Plants

Our Mission

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To grow a greener city for future generations by inspiring Angelenos to plant, care, and advocate for trees.

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Our Vision

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We envision an L.A. in which people in every neighborhood have equal access to trees & their benefits – clean air, better health, cooling shade, energy efficiency, and a friendlier, more vibrant neighborhood.

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Our Impact

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• 200 free tree adoption events hosted annually

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• 14,000 trees delivered and distributed to Angelenos annually for private property

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• 2,000+ street trees planted in LA annually

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• Hundreds volunteers at various community tree-planting events annually (pre COVID-19)

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City Partners

Non-Profit Partners

The City Plants Collaborative

Canopy Inequity: Urban Forestry Context in LA

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“Los Angeles has approximately 10.8 million trees...Accounting for 700,000 street trees and 300,000 park trees, this approximates 90% of the City’s urban forest existing on private property and open space.”

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LA’s Green New Deal

Complete a

tree inventory by 2021

Plant and maintain 90,000 trees citywide

Increase tree canopy in areas of greatest need by 50% by 2028

Complete an Urban Forest Management Plan by 2028

An Uneven Canopy

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• L.A.’s canopy distribution:

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High: 37%

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Low: 10%

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Average: 21.63%

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• Low-canopy communities suffer from higher rates of extreme-heat related illnesses & deaths

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• Lack of access to green-space poses severe public health risks & threatens the vitality of our communities

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Image Source: SavATree Consulting Group, University of Vermont Spatial Analysis Laboratory, TreePeople, & Loyola Marymount University Center for Urban Resilience. Los Angeles County Tree Canopy Assessment, 2016.

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Redlining in Los Angeles

Canopy Inequity: Urban Forestry Context in LA

We need to plan & plant TODAY for an equitable, climate-resilient LA for ALL Angelenos

Urban Forest Equity Visiting Scholar:

Dr. Vivek Shandas

• Project Goals:
• Make GIS-informed recommendations and assess policy shifts needed to achieve the Mayor’s Green New Deal goal of a 50% increase in tree canopy in disadvantaged communities by 2028.
• Analyzing currently available plantable space and the potential for urban canopy expansion and prioritization through a public health and equity lens
• Project Duration: July 2020 – March 2021
• Project Funding: Accelerate Resilience LA via TreePeople
• Project Management: City Plants

“We need to find better ways to navigate competing priorities for space, because space is what is ultimately limited but most valuable (for planting).”

- StreetsLA

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“Trees need to be seen not as a luxury but as essential on every corridor.”

-LA Great Streets Program

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“Us, as the city, figuring out a better system for maintaining our trees could really help. My sense is that there are conflicting policies around planning and building department rules and guidelines which make it hard for trees to fit in.”

-LA Mayor’s Office

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“We are not there to decorate, we are there to address and heal community pain.”

-Accelerate Resilience Los Angeles

Phase 1: Interviews

The Framework: Tree Planting ‘Tiers’

How do we locate available tree planting locations in LA in the communities that deserve trees most? GIS presents one possible solution!

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Finding space to plant trees in low canopy, disinvested, previously redlined communities is complex, as there is limited and competing space. Parkways are often not as big or wide as they are in non-redlined, wealthier, and whiter communities.

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Tier 1 is the lowest hanging fruit. How can we find currently plantable, open parkways to target planting initiatives?

If we planted all available space immediately, would we reach the Green New Deal Goal?

Cindy Chen’s Tier 1 GIS Analysis: Right Tree, Right Place

• Purpose:
• To identify parkways and private property locations that are readily available for planting to increase canopy equity, using GIS to create an automated process
• Objectives:
• Create a ModelBuilder to automate the process of finding vacant sites, using StreetsLA’s Tree Spacing Guidelines as parameters
• Plot points as “trees” in located vacant sites and project possible tree canopy spread into the future
• Determine how far Tier 1 will get us in advancing tree equity

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Phase 2: GIS & Case Study Analysis at the Street Level

Tier 1

• Parkway Analysis:
• ModelBuilder1 (MB1): StreetsLA’s Tree Spacing Guidelines act as parameters and pick up parkways that are available to plant�
• ModelBuilder2 (MB2): “Tree” points are dropped into the parkway based on parkway length and are equally spaced�
• Conducted on the entire city and split into council districts�
• Private Property Analysis:
• ModelBuilder3 (MB3): Picked up available planting locations based on buffering existing tree canopy and buildings �
• Conducted on council districts that fall below LA’s average tree canopy (~21.63%)

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Phase 2: GIS & Case Study Analysis at the Street Level

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Step 1: Sourcing the Data

• StreetsLA, Urban Forestry Division’s Tree Spacing Guidelines provided a list of datasets used as parameters in the parkway GIS analysis
• Most of the existing infrastructure datasets were found on the Los Angeles GeoHub or were obtained through various agencies within the City of Los Angeles.
• Despite attempts, we were unsuccessful in obtaining datasets for water meters, gas meters, and electrical power poles which impacted overall tree canopy projections

Phase 2: GIS & Case Study Analysis at the Street Level

Table 1: List of the datasets used in Cindy’s Tier 1 Parkway Analysis with their respective distances.

Step 2: Data Modifications

Phase 2: GIS & Case Study Analysis at the Street Level

• Projections:
• All the datasets were projected in CA State Plane V for the analysis
• Subdivision of Parkway Polygons:
• The parkways were subdivided into 25 ft² polygons to pick up available locations instead of removing one whole parkway polygon
• Removing Duplicate Entries and Parks:
• Some alley entrances were shown as driveways so we removed the duplicated alley polygons
• Parks and large polygon shapes for grasses and soils were removed as they are not part of the Private Property Analysis
• Curbs and Sidewalks:
• We modified the curbs layer by only selecting the sidewalk ramps and placed a point at the center of each curb
• Raster Reclassification and conversion to Vector

Parkways Analysis: ModelBuilder 1 (MB1)

Step 3: Create & Run the ModelBuilders

Parkways Analysis: ModelBuilder 2 (MB2)

Private Property Analysis: ModelBuilder 3 (MB3)

Parkways Analysis

Step 4: Tree Canopy Projections

• We calculated the number of trees that fit inside the selected polygon
• MB2 dropped “tree” points inside the selected parkways according to the calculations
• A buffer was used on the “tree” points as canopy spread
• We used a small tree canopy spread of 15 feet for the analysis

Private Property Analysis

Step 4: Tree Canopy Projections

• We “planted” 1 tree for each grass & soil polygon
• There were a range in sizes so we selected polygons with an area ≥100 ft² and ≤ 20,000 ft²
• A “tree” point was dropped in the centroid of each grass & soil polygon
• A buffer was used on the “tree” points as canopy spread
• We used a small tree canopy spread of 15 feet for the analysis

A Note on the Parkway ModelBuilder (MB1) Accuracy

What about StreetsLA’s tree inventory?

• Davey is also noting vacant sites as they complete the Street Tree Inventory
• We used Davey’s data to test accuracy on MB1
• We intersected Davey’s Vacant Sites locations (red) with the selected subdivided parkways (yellow)
• 74.50% of Davey’s vacant sites were picked up by the ModelBuilder, proving the accuracy
• Davey also included empty tree wells as vacant sites that were not picked up in the parkway analysis and intersection
• This could account for the margin of error in the modelbuilder’s accuracy

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Parkway Analysis: Council District 15 - Before & After Tier 1

Private Property Analysis: Council District 9 - Before & After Tier 1

Case Study: Welland Ave - Before & After Tier 1

Tier 1 ModelBuilder located 75 street trees and 66 private properties trees as available for planting

Tier 1 Results

Tier 1 Citywide Results

Thank you! Questions?