A single GPX from under trees is not that accurate. Such paths are often visible on LIDAR / DTM / ALS layers. There is also New Strava Heatmap Extension for iD for which you will need a strava login (gratis) where you can see what other peoples GPS’ recorded 
PS: There is no link to Strava Global Heatmap on the landing page. For your convenience. When logged in, the overlay comes with higher resolution.