Estimates of Cambridge Tree Canopy
The City of Cambridge has published multiple estimates of tree canopy coverage for the years 2009, 2014, 2018 and 2020. This report compares the estimates from the various sources and years.
Sources
Tree canopy estimates are available in both published reports and in data files available from Cambridge GIS.
Published reports
The published reports include
- A Report on the City of Cambridge’s Existing and Possible Tree Canopy
- Published June 1, 2012
- Canopy estimate for 2009
- Tree Canopy in Cambridge, MA: 2009-2014
- Published February 2, 2018
- Canopy estimates (in chart only) for 2009 and 2014
- Tree Canopy Assessment, Cambridge, MA
- Published February 19, 2020
- Canopy estimates for 2014 and 2018
- Tree Canopy Assessment, Cambridge, MA 2009-2020
- Published October 12, 2022
- Canopy estimates for 2009, 2014, 2018 and 2020
With the exception of the report published in 2018, these reports include canopy estimates in acres in the text of the report. The 2018 report only reports the estimates in a chart. For this report, the chart was digitized to obtain the estimates.
GIS data
The GIS data sets available include
- Tree Canopy 2009 (data for 2009)
- Tree Canopy 2014 (data for 2014)
- Tree Canopy 2018 (data for 2018)
- Tree Canopy Change 2009 2014 (data for 2009 and 2014)
- Tree Canopy Change 2014 2018 (data for 2014 and 2018)
- Tree Canopy 2022 (data for 2009, 2014, 2018 and 2020)
The GIS data sets are shapefiles which show the actual outline of the tree canopy. The area of the outlines gives an estimate of the total canopy area. With the exception of the 2022 data set, the published data includes portions of canopy data which are outside the Cambridge City limits. For this report, the outlines were clipped to the City limits before calculating area.
Tree canopy estimates
This table gives the available tree canopy estimates from each of the above sources.
| Estimates of Cambridge tree canopy size | ||||
| Values from published reports and GIS data sets | ||||
| Source | Year | |||
|---|---|---|---|---|
| 2009 | 2014 | 2018 | 2020 | |
| 2012 report | 1222 | - | - | - |
| 2009 data, trimmed | 1220 | - | - | - |
| 2018 report (est) | 1271 | 1173 | - | - |
| 2020 report | 1222 | 1151 | 1040 | - |
| 2014 data, trimmed | - | 1167 | - | - |
| 2014-2018 data, trimmed | - | 1151 | 1040 | - |
| 2018 data, trimmed | - | - | 1040 | - |
| 2022 report | 1092 | 944 | 1012 | 1045 |
| 2020 data | 1092 | 944 | 1012 | 1045 |
| Data: City of Cambridge | Analysis: Kent S Johnson | ||||
This chart shows the estimates graphically.
Conclusions
The 2009 and 2014 estimates from the 2022 report and data are significantly different from other estimates for those years, and the 2018 estimates are slightly different. The 2022 report attributes this to a reprocessing of the earlier data.
With one exception, the estimates from the written reports agree closely with the estimates from the corresponding data. The sole exception is the 2009 estimate from the chart in the 2018 report, which differs somewhat from the other 2009 estimates.
Copyright 2023 Kent S Johnson 
2023-02-24