Several tree registers from individual cities—mostly in Europe—have been directly imported into Open Street Map.
How to access:
Data is downloadable in several feature layer formats, including shapefiles. The spatial coverage is patchy and appears to lean heavily towards the United States and UK. Access may require a higher technical capacity to access and use. To download all data for a specific country, click “Export,” select “Geofabrik Downloads,” and follow the subsequent prompts. Individual tree records can be searched with “tags”. See more information on the OpenStreetMap Wiki.