cycle route - tree root

Milton Keynes is (quite) well known for its extensive network of cycle paths (not to be confused with psychopaths, a local term for the inhabitants of the extensive road system). 

Known as 'Redways', the cycle paths criss-cross the city, providing a traffic-free way of getting to and from school/work/shops.  At least that's the theory.

When I moved here 40 years ago (can it really be that long?) they fulfilled that function admirably.  They were even red in colour.  

Now many are in need of repair, full of potholes, broken glass and tree roots bubbling up through the asphalt - an unforeseen consequence perhaps of MK now being the most populated tree city in the UK. 

On our ride this morning we came across not just a tree root, but an actual tree in the middle of the Redway.  Mother Nature or deliberate planting?

If deliberate, I can only conclude that the planners obsession with roundabouts extends beyond the roads.