Just look at the two full scale commercial quarries located on the Chase to see why there are pebbles everywhere. The forest is sat on one of Europe’s largest sand and gravel deposits.
In the early days money was tight and there was a resistance by the powers towards using imported material and this has helped keep much of the trail network looking less obtrusive than it would have been had we used imported material such as crushed Limestone.
If imported material had been used in the Monkey then it would have cost too much for the budget available at the time.
All said though it’s not a massive issue for me, although it does seem to be for others.
New trail construction and overhauls to the existing trails is now done with a 50/50 mix of local sand/gravel and imported crushed gritstone. This gives what is hoped to be a good balance between durability, grip, cost and aesthetics