Probably the switch to OSM map data. Either the wooded areas are not
marked as such in OpenStreetMaps, or they are tagged in a way that the
data did not get loaded in the
aprs.fi map tile server.
Please compare against
https://www.openstreetmap.org/ - if the trees are
not growing there, tap "Log in" or "Sign Up", then "Edit", and
plant them. :)
If they're growing on
openstreetmap.org, please provide a link to
https://www.openstreetmap.org/ where they are, with the coordinates in the
link, and I'll see if I can get them imported in the next DB rebuild.
- Hessu