Canopy cover time series
Canopy cover rose from 29.6% in 1978 to 40.9% in 2020. Most of the gain came between 1978 and 1996 (0.53% a year), driven by forest landscapes and the reforestation of farmland.
Research Products / Open dataset
Peel Urban Forest Change, 1944–2020
Open data and code on how tree canopy has changed across the Region of Peel, southern Ontario, from 1944 aerial photographs and tree rings to annual 30 m Landsat canopy cover maps for 1972–2020.
1972–2020Yearly 30 m canopy cover maps
0.89R², canopy cover time series
1,600Residential dissemination areas
20Tree-ring records from 16 sites
Overview
The Region of Peel (Mississauga, Brampton and Caledon) grew from about 32,000 people in 1941 to about 1.5 million in 2020, and its tree canopy changed along with it. This collection brings together the open data and code from the doctoral research of Dr. Mitchell Bonney with Prof. Yuhong He. At its centre is a yearly 30 m tree canopy cover time series for 1972–2020, built from Landsat imagery.
Across the historically treed part of the study area, canopy cover rose from 29.6% in 1978 to 40.9% in 2020. Companion datasets map canopy in residential neighbourhoods since 1972 and in each municipality in 2018, record tree density from aerial photographs taken since 1944, and provide tree-ring measurements from 16 forest stands.
These data can support urban forest management and planning in the Region of Peel and the Credit River Watershed. The canopy maps and time series can be used to track progress toward municipal canopy targets, identify neighbourhoods with less access to tree canopy, evaluate how development, reforestation, tree planting, drought, pests and storms have shaped the canopy, and anticipate how canopy will change as new neighbourhoods age. They also offer municipalities a low-cost way to monitor canopy cover every year with free Landsat imagery.
Canopy and inequality
After falling by more than 5% in the decade after 1972, residential canopy has stayed at 18–20% in Mississauga and 13–16% in Brampton. It is higher where population density is lower and where fewer residents are members of visible minorities.
Municipal canopy maps
Caledon has 34% canopy cover, Mississauga 17.5% and Brampton 15.9%. Against residential canopy criteria, Caledon rates “Good”, Mississauga “Moderate” and Brampton “Low”.
Maps
Figures reproduced from Bonney & He (2025) and Bonney & He (2026), Canadian Journal of Remote Sensing, open access under CC BY 4.0. The banner is a crop of Figure 10 of Bonney & He (2025).
What’s included
- Tree canopy cover time series, 1972–2020Zenodo · CC BY 4.0. Yearly canopy cover predictions (cc_72to20.tif, 392 MB), a mask of consistently non-canopy areas, a water mask, and Yearly.zip (6.3 GB) with the annual predictors, including the CC10 forest mask.
- Residential canopy cover and inequality, 1972–2020Zenodo · CC BY 4.0. Yearly 30 m canopy cover predictions for residential areas, a raster of the year each residential pixel transitioned to a developed state, and a raster of the LandTrendr tasseled cap angle biggest-loss end year. Supplementary figures are on the Taylor & Francis figshare.
- Municipal canopy cover mapping, 2018Zenodo · CC BY 4.0. Six archives: the study area, plus 2018 field reference data, aerial canopy cover reference data, canopy cover predictions, accuracy assessment and case studies.
- Suburbanizing tree density, 1944–2017Zenodo · CC BY 4.0. Data from a study of six landscapes in Mississauga, based on individual trees interpreted from leaf-off aerial photographs taken between 1944 and 2017. The high-resolution imagery is not included.
- Tree-ring records (ITRDB CANA653–CANA672)NOAA NCEI World Data Service for Paleoclimatology. Twenty ring-width records from 16 forest sites in southern Ontario, each with its own DOI, spanning 1868 to 2018. Species: sugar maple, red oak, eastern hemlock, northern white-cedar, eastern white pine, balsam poplar, Norway spruce and paper birch.
- Code (GitHub, MIT licence)PredictTreeCC_Landsat_1972to2020 (2018 mapping, the 1972–2020 time series and residential canopy analysis) · SuburbanizingTreeDensity_1944to2017 · LandsatVsTreerings_1972to2018
Cite
Bonney, M. T., & He, Y. (2025). Using Landsat time-series to investigate nearly 50 years of tree canopy cover change across an urban-rural landscape in southern Ontario. Canadian Journal of Remote Sensing, 51(1), 2445836. https://doi.org/10.1080/07038992.2024.2445836
The companion datasets are described in these articles:
- Residential canopy cover, 1972–2020Bonney, M. T., & He, Y. (2026). Leveraging the full potential of Landsat to investigate inequalities in post-development residential canopy cover (1972–2020). Canadian Journal of Remote Sensing, 52(1), 2622730. https://doi.org/10.1080/07038992.2026.2622730
- Municipal canopy cover, 2018Bonney, M. T., He, Y., Vogeler, J., Conway, T., & Kaye, E. (2024). Mapping canopy cover for municipal forestry monitoring: Using free Landsat imagery and machine learning. Urban Forestry & Urban Greening, 100, 128490. https://doi.org/10.1016/j.ufug.2024.128490
- Tree density, 1944–2017Bonney, M. T., & He, Y. (2019). Attributing drivers to spatio-temporal changes in tree density across a suburbanizing landscape since 1944. Landscape and Urban Planning, 192, 103652. https://doi.org/10.1016/j.landurbplan.2019.103652 Awarded first paper award in Geography at UTM.
- Tree rings and Landsat, 1972–2018Bonney, M. T., & He, Y. (2021). Temporal connections between long-term Landsat time-series and tree-rings in an urban–rural temperate forest. International Journal of Applied Earth Observation and Geoinformation, 103, 102523. https://doi.org/10.1016/j.jag.2021.102523
Contact
Questions about the data, the methods or collaboration on urban forest monitoring are welcome. Please get in touch with the laboratory.
For other enquiries, see the lab contact page.
Prof. Yuhong He
Principal Investigator, RSSEM Lab
Department of Geography, Geomatics and Environment, University of Toronto Mississauga
- Phone
- 905-569-4679
- Office
- DV3271, William G. Davis Building
- Address
- 3359 Mississauga Road, Mississauga, ON L5L 1C6