Please see https://wiki.openstreetmap.org/wiki/Historic

It says "Please note that OSM is not collecting information about historic events. We are not mapping places just because something has occurred there in the past, rather we map things which are STILL OBSERVABLE." 

Very few tumuli in Pipstorn Wood meet this criterion; only a small number are observable by people walking in the wood. Nearly all of the tumuli presently shown on the map are weathered beyond recognition and have not been restored. People can walk across one of these sites without noticing anything at all. Since they are not observable, they are not of interest to a normal map user.  This all means most of the Pipstorn tumulus sites are not relevant to Open Street Map. 

An enthusiast wanting more information can see a particularly detailed map at https://sdfikort.dk/spatialmap, and then click on Landtemaer, Fortidsminder fredet. The map provides outline details (in Danish) for each of the relics and a link to a detailed page about the relic. The information available at sdfikort.dk goes far beyond anything Open Street Map can offer.

To illustrate the irrelevance of these sites to Open Street Map, here is an example of the detailed pages at sdfikort.dk. See https://www.kulturarv.dk/fundogfortidsminder/Lokalitet/190943/   Click on the picture to enlarge it.

Here is another; https://www.kulturarv.dk/fundogfortidsminder/Lokalitet/190941/     Click on the picture to enlarge it.

These patches of grass purport to be tumuli in Pipstorn Wood!  Many of the other so-called tumuli in Pipstorn Wood are even worse, and do not even merit a photograph.

Quod erat demonstrandum.
