I used to work for the USFS surveying old growth timber, regen surveys, and EIS work. This was back in the day when GPS was just coming available but we used maps, paper, compass, and aerial photos.
It's amazing that one was able to find the corners or edges of timber stands that needed to be surveyed and one could navigate just fine once an corner or edge of an particular stand was identified and you could then draw an map with transect lines and plots. Aerial photos and training to interpret helped to some degree as well, and the old chain or pace pole helped keep accurate counts for distances and even helped keep one more inline with less deviation in the heavy thick stuff.
There were some forests I worked on that were both current and former mining districts. At times there were large mineralized outcrops that defeated my compass, but that's not too much of a worry if you've draw out transect lines and use the terrain and pace pole to shoot a rough sighting and
