This interactive map provides a comprehensive view of Lodi's urban tree canopy — how much
we have, where it's concentrated, where it's declining, and where new planting is making
a difference. The goal is to give residents, city staff, and community organizations a
shared, data-driven picture of Lodi's urban forest so that planting efforts, shade
equity initiatives, and long-term canopy goals can be grounded in evidence.
Satellite Baseline (2022)
The foundation layer is the CAL FIRE / USDA Forest Service California Urban Tree
Canopy dataset, produced by EarthDefine and Dewberry from 2022 NAIP aerial
imagery classified at 60cm resolution with 97.3% urban accuracy. This satellite data
provides the definitive measurement of canopy coverage across every census tract — the
percentages, acreages, and 2018-to-2022 change values shown in the map and grid.
Estimated Canopy Growth (Post-2022)
Because the satellite imagery is a snapshot frozen in 2022, we overlay an estimated
canopy growth layer built from Lodi's actual tree inventory records. When the
"Estimated Tree Canopy" layer is enabled, the map displays modeled crown diameters for
5,881 trees from three sources, and the grid adds columns showing estimated 2023–25
canopy, recent change, and growth acreage per tract.
How Crown Diameters Are Calculated
Public Works trees (12,648 inventoried): Each tree has a confirmed
species, GPS location, and planting date in the city's inventory. Crown diameter is
estimated using USDA Forest Service allometric equations (Peper et al. 2001), which
predict crown width from species and age. Of the 4,892 trees planted 2019–2022, the
model calculates how much their crown has grown since the 2022 imagery was captured. For
38 trees planted after 2022, the full estimated crown area is counted as new canopy.
Tree Lodi trees (422 inventoried, 108 post-2022): These
community-planted trees use the same allometric approach — species and planting date are
recorded at the time of planting, and crown diameter is modeled identically to Public
Works trees.
Shade Tree program (843 deliveries): The Shade Tree program delivers
free trees to Lodi residents. Unlike Public Works and Tree Lodi trees, Shade Tree
records contain the delivery address and species but not a GPS-confirmed
planting location within the property. Crown diameters are calculated using
the same allometric equations, but each tree is geocoded to its delivery address rather
than a surveyed trunk location. Because homeowner-planted trees may be sited in front
yards, back yards, or side yards — and some may not survive transplanting — the Shade
Tree estimates carry more spatial uncertainty than professionally planted inventory
trees. The Conservative / Moderate / Optimistic estimation modes help bracket this
uncertainty.
Estimation Modes
The crown diameter toggle adjusts all estimated crowns by a scaling factor: Conservative
(0.70×) reduces diameters 30% to account for pruning, competition, and Central
Valley water stress. Moderate (1.00×) uses the USDA allometric mean
directly. Optimistic (1.35×) increases diameters 35% for irrigated,
open-grown, favorable conditions. The grid and panel statistics update in real time as
the mode changes.
Two Types of Growth
The model distinguishes between two categories. Canopy growth (shown in
blue) represents trees planted 2019–2022 that were small when the satellite imagery was
captured but have since grown — the model calculates the difference between their
estimated 2025 crown area and their 2022 crown area. New trees (shown
in red) were planted after the 2022 imagery and represent entirely new canopy not
captured in the satellite baseline.
June 2026 update: The estimated canopy layer will be refreshed to
include all late 2025 and early 2026 tree plantings from Public Works, Tree Lodi, and
Shade Tree program records as they become available.
