I was drawing the comparison between the routes that we drive and greenlanes. The forestry tracks (on a private estate) are very similar in nature to greenlanes, and we use them every day- hence the comment that the impact when driven properly is negligable compared to other tyres we have previously used- it provides a pretty effective 'control' experiment I would say?- Same routes, different tyres, similar environment to greenlanes?
And yes, in our training area (formerly a golf course) there are areas of pretty bottomless peat, but as the area has been previously scarred the estate are not to fussed about us using it- seen as it is essentially dead ground, not suitable for any other use!