Hi, It looks like your landcover tag is being used wrongly, the areas you've mapped are actually individual trees or tree lines as you've previously accepted. As such OSM practice says they should be nodes or linear features not area features. Whatever you add to OSM should be correct ground truth and verifiably. So features of temporary or personal nature should not be added. Thus the landcover tagged areas should be removed. 

You can map temporary or personal features with JOSM and save them without uploading to the OSM database. Perhaps you could use this method ASAP to hold the landcover features for you future use.  

OSM is a live worldwide database from which thousands of maps are compiled. Other users have a right to expect it to be consistent, so I'll continue to correct anyones mapping in order to better OSM. 